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[ttfautohint.git] / lib / tafpgm.c

/* tafpgm.c */

/*
 * Copyright (C) 2011-2013 by Werner Lemberg.
 *
 * This file is part of the ttfautohint library, and may only be used,
 * modified, and distributed under the terms given in `COPYING'.  By
 * continuing to use, modify, or distribute this file you indicate that you
 * have read `COPYING' and understand and accept it fully.
 *
 * The file `COPYING' mentioned in the previous paragraph is distributed
 * with the ttfautohint library.
 */


#include "ta.h"


/* we need the following macro */
/* so that `func_name' doesn't get replaced with its #defined value */
/* (as defined in `tabytecode.h') */

#define FPGM(func_name) fpgm_ ## func_name


/*
 * Due to a bug in FreeType up to and including version 2.4.7,
 * it is not possible to use MD_orig with twilight points.
 * We circumvent this by using GC_orig.
 */
#define MD_orig_fixed \
  GC_orig, \
  SWAP, \
  GC_orig, \
  SWAP, \
  SUB

#define MD_orig_ZP2_0 \
  MD_orig_fixed

#define MD_orig_ZP2_1 \
  PUSHB_1, \
    0, \
  SZP2, \
  MD_orig_fixed, \
  PUSHB_1, \
    1, \
  SZP2


/* a convenience shorthand for scaling; see `bci_cvt_rescale' for details */
#define DO_SCALE \
  DUP, /* s: a a */ \
  PUSHB_1, \
    cvtl_scale, \
  RCVT, \
  MUL, /* delta * 2^10 */ \
  PUSHB_1, \
    cvtl_0x10000, \
  RCVT, \
  DIV, /* delta */ \
  ADD /* a + delta */


/* in the comments below, the top of the stack (`s:') */
/* is the rightmost element; the stack is shown */
/* after the instruction on the same line has been executed */


/*
 * bci_round
 *
 *   Round a 26.6 number.  Contrary to the ROUND bytecode instruction, no
 *   engine specific corrections are applied.
 *
 * in: val
 *
 * out: ROUND(val)
 */

unsigned char FPGM(bci_round) [] =
{

  PUSHB_1,
    bci_round,
  FDEF,

  PUSHB_1,
    32,
  ADD,
  FLOOR,

  ENDF,

};


/*
 * bci_smooth_stem_width
 *
 *   This is the equivalent to the following code from function
 *   `ta_latin_compute_stem_width':
 *
 *      dist = ABS(width)
 *
 *      if (stem_is_serif
 *          && dist < 3*64)
 *         || is_extra_light:
 *        return width
 *      else if base_is_round:
 *        if dist < 80
 *          dist = 64
 *      else if dist < 56:
 *        dist = 56
 *
 *      delta = ABS(dist - std_width)
 *
 *      if delta < 40:
 *        dist = std_width
 *        if dist < 48
 *          dist = 48
 *        goto End
 *
 *      if dist < 3*64:
 *        delta = dist
 *        dist = FLOOR(dist)
 *        delta = delta - dist
 *
 *        if delta < 10:
 *          dist = dist + delta
 *        else if delta < 32:
 *          dist = dist + 10
 *        else if delta < 54:
 *          dist = dist + 54
 *        else
 *          dist = dist + delta
 *      else
 *        dist = ROUND(dist)
 *
 *    End:
 *      if width < 0:
 *        dist = -dist
 *      return dist
 *
 *
 * in: width
 *     stem_is_serif
 *     base_is_round
 *
 * out: new_width
 *
 * CVT: cvtl_is_extra_light
 *      std_width
 *
 * uses: bci_round
 */

unsigned char FPGM(bci_smooth_stem_width_a) [] =
{

  PUSHB_1,
    bci_smooth_stem_width,
  FDEF,

  DUP,
  ABS, /* s: base_is_round stem_is_serif width dist */

  DUP,
  PUSHB_1,
    3*64,
  LT, /* dist < 3*64 */

  PUSHB_1,
    4,
  MINDEX, /* s: base_is_round width dist (dist<3*64) stem_is_serif */
  AND, /* stem_is_serif && dist < 3*64 */

  PUSHB_1,
    cvtl_is_extra_light,
  RCVT,
  OR, /* (stem_is_serif && dist < 3*64) || is_extra_light */

  IF, /* s: base_is_round width dist */
    POP,
    SWAP,
    POP, /* s: width */

  ELSE,
    ROLL, /* s: width dist base_is_round */
    IF, /* s: width dist */
      DUP,
      PUSHB_1,
        80,
      LT, /* dist < 80 */
      IF, /* s: width dist */
        POP,
        PUSHB_1,
          64, /* dist = 64 */
      EIF,

    ELSE,
      DUP,
      PUSHB_1,
        56,
      LT, /* dist < 56 */
      IF, /* s: width dist */
        POP,
        PUSHB_1,
          56, /* dist = 56 */
      EIF,
    EIF,

    DUP, /* s: width dist dist */
    PUSHB_1,

};

/*    %c, index of std_width */

unsigned char FPGM(bci_smooth_stem_width_b) [] =
{

    RCVT,
    SUB,
    ABS, /* s: width dist delta */

    PUSHB_1,
      40,
    LT, /* delta < 40 */
    IF, /* s: width dist */
      POP,
      PUSHB_1,

};

/*      %c, index of std_width */

unsigned char FPGM(bci_smooth_stem_width_c) [] =
{

      RCVT, /* dist = std_width */
      DUP,
      PUSHB_1,
        48,
      LT, /* dist < 48 */
      IF,
        POP,
        PUSHB_1,
          48, /* dist = 48 */
      EIF,

    ELSE,
      DUP, /* s: width dist dist */
      PUSHB_1,
        3*64,
      LT, /* dist < 3*64 */
      IF,
        DUP, /* s: width delta dist */
        FLOOR, /* dist = FLOOR(dist) */
        DUP, /* s: width delta dist dist */
        ROLL,
        ROLL, /* s: width dist delta dist */
        SUB, /* delta = delta - dist */

        DUP, /* s: width dist delta delta */
        PUSHB_1,
          10,
        LT, /* delta < 10 */
        IF, /* s: width dist delta */
          ADD, /* dist = dist + delta */

        ELSE,
          DUP,
          PUSHB_1,
            32,
          LT, /* delta < 32 */
          IF,
            POP,
            PUSHB_1,
              10,
            ADD, /* dist = dist + 10 */

          ELSE,
            DUP,
            PUSHB_1,
              54,
            LT, /* delta < 54 */
            IF,
              POP,
              PUSHB_1,
                54,
              ADD, /* dist = dist + 54 */

            ELSE,
              ADD, /* dist = dist + delta */

            EIF,
          EIF,
        EIF,

      ELSE,
        PUSHB_1,
          bci_round,
        CALL, /* dist = round(dist) */

      EIF,
    EIF,

    SWAP, /* s: dist width */
    PUSHB_1,
      0,
    LT, /* width < 0 */
    IF,
      NEG, /* dist = -dist */
    EIF,
  EIF,

  ENDF,

};


/*
 * bci_get_best_width
 *
 *   An auxiliary function for `bci_strong_stem_width'.
 *
 * in: n (initialized with CVT index for first vertical width)
 *     dist
 *
 * out: n+1
 *      dist
 *
 * sal: sal_best
 *      sal_ref
 *
 * CVT: widths[]
 */

unsigned char FPGM(bci_get_best_width) [] =
{

  PUSHB_1,
    bci_get_best_width,
  FDEF,

  DUP,
  RCVT, /* s: dist n w */
  DUP,
  PUSHB_1,
    4,
  CINDEX, /* s: dist n w w dist */
  SUB,
  ABS, /* s: dist n w d */
  DUP,
  PUSHB_1,
    sal_best,
  RS, /* s: dist n w d d best */
  LT, /* d < best */
  IF,
    PUSHB_1,
      sal_best,
    SWAP,
    WS, /* best = d */
    PUSHB_1,
      sal_ref,
    SWAP,
    WS, /* reference = w */

  ELSE,
    POP,
    POP,
  EIF,

  PUSHB_1,
    1,
  ADD, /* n = n + 1 */

  ENDF,

};


/*
 * bci_strong_stem_width
 *
 *   This is the equivalent to the following code (function
 *   `ta_latin_snap_width' and some lines from
 *   `ta_latin_compute_stem_width'):
 *
 *     best = 64 + 32 + 2;
 *     reference = width
 *     dist = ABS(width)
 *
 *     for n in 0 .. num_widths:
 *       w = widths[n]
 *       d = ABS(dist - w)
 *
 *       if d < best:
 *         best = d
 *         reference = w;
 *
 *     if dist >= reference:
 *       if dist < ROUND(reference) + 48:
 *         dist = reference
 *     else
 *       if dist > ROUND(reference) - 48:
 *         dist = reference
 *
 *     if dist >= 64:
 *       dist = ROUND(dist)
 *     else
 *       dist = 64
 *
 *     if width < 0:
 *       dist = -dist
 *     return dist
 *
 * in: width
 *     stem_is_serif (unused)
 *     base_is_round (unused)
 *
 * out: new_width
 *
 * sal: sal_best
 *      sal_ref
 *
 * CVT: widths[]
 *
 * uses: bci_get_best_width
 *       bci_round
 */

unsigned char FPGM(bci_strong_stem_width_a) [] =
{

  PUSHB_1,
    bci_strong_stem_width,
  FDEF,

  SWAP,
  POP,
  SWAP,
  POP,
  DUP,
  ABS, /* s: width dist */

  PUSHB_2,
    sal_best,
    64 + 32 + 2,
  WS, /* sal_best = 98 */

  DUP,
  PUSHB_1,
    sal_ref,
  SWAP,
  WS, /* sal_ref = width */

  PUSHB_3,
};

/*  %c, first index of vertical widths */
/*  %c, number of vertical widths */

unsigned char FPGM(bci_strong_stem_width_b) [] =
{

    bci_get_best_width,
  LOOPCALL,

  POP, /* s: width dist */
  DUP,
  PUSHB_1,
    sal_ref,
  RS, /* s: width dist dist reference */
  DUP,
  ROLL,
  DUP,
  ROLL,
  PUSHB_1,
    bci_round,
  CALL, /* s: width dist reference dist dist ROUND(reference) */
  PUSHB_2,
    48,
    5,
  CINDEX,
  ROLL, /* s: width dist reference dist ROUND(reference) 48 reference dist */

  LTEQ, /* dist >= reference */
  IF, /* s: width dist reference dist ROUND(reference) 48 */
    ADD,
    LT, /* dist < ROUND(reference) + 48 */

  ELSE,
    SUB,
    GT, /* dist > ROUND(reference) - 48 */
  EIF,

  IF,
    SWAP, /* s: width reference dist */
  EIF,
  POP,

  DUP,
  PUSHB_1,
    64,
  GTEQ, /* dist >= 64 */
  IF,
    PUSHB_1,
      bci_round,
    CALL, /* dist = ROUND(dist) */

  ELSE,
    POP,
    PUSHB_1,
      64, /* dist = 64 */
  EIF,

  SWAP, /* s: dist width */
  PUSHB_1,
    0,
  LT, /* width < 0 */
  IF,
    NEG, /* dist = -dist */
  EIF,

  ENDF,

};


/*
 * bci_do_loop
 *
 *   An auxiliary function for `bci_loop'.
 *
 * sal: sal_i (gets incremented by 2 after execution)
 *      sal_func
 *
 * uses: func[sal_func]
 */

unsigned char FPGM(bci_loop_do) [] =
{

  PUSHB_1,
    bci_loop_do,
  FDEF,

  PUSHB_1,
    sal_func,
  RS,
  CALL,

  PUSHB_3,
    sal_i,
    2,
    sal_i,
  RS,
  ADD, /* sal_i = sal_i + 2 */
  WS,

  ENDF,

};


/*
 * bci_loop
 *
 *   Take a range `start'..`end' and a function number and apply the
 *   associated function to the range elements `start', `start+2',
 *   `start+4', ...
 *
 * in: func_num
 *     end
 *     start
 *
 * sal: sal_i (counter initialized with `start')
 *      sal_func (`func_num')
 *
 * uses: bci_loop_do
 */

unsigned char FPGM(bci_loop) [] =
{

  PUSHB_1,
    bci_loop,
  FDEF,

  PUSHB_1,
    sal_func,
  SWAP,
  WS, /* sal_func = func_num */

  SWAP,
  DUP,
  PUSHB_1,
    sal_i,
  SWAP,
  WS, /* sal_i = start */

  SUB,
  PUSHB_1,
    2*64,
  DIV,
  PUSHB_1,
    1,
  ADD, /* number of loops ((end - start) / 2 + 1) */

  PUSHB_1,
    bci_loop_do,
  LOOPCALL,

  ENDF,

};


/*
 * bci_cvt_rescale
 *
 *   Rescale CVT value by `cvtl_scale' (in 16.16 format).
 *
 *   The scaling factor `cvtl_scale' isn't stored as `b/c' but as `(b-c)/c';
 *   consequently, the calculation `a * b/c' is done as `a + delta' with
 *   `delta = a * (b-c)/c'.  This avoids overflow.
 *
 * in: cvt_idx
 *
 * out: cvt_idx+1
 *
 * CVT: cvtl_scale
 *      cvtl_0x10000
 */

unsigned char FPGM(bci_cvt_rescale) [] =
{

  PUSHB_1,
    bci_cvt_rescale,
  FDEF,

  DUP,
  DUP,
  RCVT,
  DO_SCALE,
  WCVTP,

  PUSHB_1,
    1,
  ADD,

  ENDF,

};


/*
 * bci_blue_round
 *
 *   Round a blue ref value and adjust its corresponding shoot value.
 *
 *   This is the equivalent to the following code (function
 *   `ta_latin_metrics_scale_dim':
 *
 *     delta = dist;
 *     if (dist < 0)
 *       delta = -delta;
 *
 *     if (delta < 32)
 *       delta = 0;
 *     else if (delta < 48)
 *       delta = 32;
 *     else
 *       delta = 64;
 *
 *     if (dist < 0)
 *       delta = -delta;
 *
 * in: ref_idx
 *
 * out: ref_idx+1
 *
 * uses: bci_round
 */

unsigned char FPGM(bci_blue_round_a) [] =
{

  PUSHB_1,
    bci_blue_round,
  FDEF,

  DUP,
  DUP,
  RCVT, /* s: ref_idx ref_idx ref */

  DUP,
  PUSHB_1,
    bci_round,
  CALL,
  SWAP, /* s: ref_idx ref_idx round(ref) ref */

  PUSHB_2,

};

/*  %c, blue_count */

unsigned char FPGM(bci_blue_round_b) [] =
{

    4,
  CINDEX,
  ADD, /* s: ref_idx ref_idx round(ref) ref shoot_idx */
  DUP,
  RCVT, /* s: ref_idx ref_idx round(ref) ref shoot_idx shoot */

  ROLL, /* s: ref_idx ref_idx round(ref) shoot_idx shoot ref */
  SWAP,
  SUB, /* s: ref_idx ref_idx round(ref) shoot_idx dist */
  DUP,
  ABS, /* s: ref_idx ref_idx round(ref) shoot_idx dist delta */

  DUP,
  PUSHB_1,
    32,
  LT, /* delta < 32 */
  IF,
    POP,
    PUSHB_1,
      0, /* delta = 0 */

  ELSE,
    PUSHB_1,
      48,
    LT, /* delta < 48 */
    IF,
      PUSHB_1,
        32, /* delta = 32 */

    ELSE,
      PUSHB_1,
        64, /* delta = 64 */
    EIF,
  EIF,

  SWAP, /* s: ref_idx ref_idx round(ref) shoot_idx delta dist */
  PUSHB_1,
    0,
  LT, /* dist < 0 */
  IF,
    NEG, /* delta = -delta */
  EIF,

  PUSHB_1,
    3,
  CINDEX,
  SWAP,
  SUB, /* s: ref_idx ref_idx round(ref) shoot_idx (round(ref) - delta) */

  WCVTP,
  WCVTP,

  PUSHB_1,
    1,
  ADD, /* s: (ref_idx + 1) */

  ENDF,

};


/*
 * bci_decrement_component_counter
 *
 *   An auxiliary function for composite glyphs.
 *
 * CVT: cvtl_is_subglyph
 */

unsigned char FPGM(bci_decrement_component_counter) [] =
{

  PUSHB_1,
    bci_decrement_component_counter,
  FDEF,

  /* decrement `cvtl_is_subglyph' counter */
  PUSHB_2,
    cvtl_is_subglyph,
    cvtl_is_subglyph,
  RCVT,
  PUSHB_1,
    1,
  SUB,
  WCVTP,

  ENDF,

};


/*
 * bci_get_point_extrema
 *
 *   An auxiliary function for `bci_create_segment'.
 *
 * in: point-1
 *
 * out: point
 *
 * sal: sal_point_min
 *      sal_point_max
 */

unsigned char FPGM(bci_get_point_extrema) [] =
{

  PUSHB_1,
    bci_get_point_extrema,
  FDEF,

  PUSHB_1,
    1,
  ADD, /* s: point */
  DUP,
  DUP,

  /* check whether `point' is a new minimum */
  PUSHB_1,
    sal_point_min,
  RS, /* s: point point point point_min */
  MD_orig,
  /* if distance is negative, we have a new minimum */
  PUSHB_1,
    0,
  LT,
  IF, /* s: point point */
    DUP,
    PUSHB_1,
      sal_point_min,
    SWAP,
    WS,
  EIF,

  /* check whether `point' is a new maximum */
  PUSHB_1,
    sal_point_max,
  RS, /* s: point point point_max */
  MD_orig,
  /* if distance is positive, we have a new maximum */
  PUSHB_1,
    0,
  GT,
  IF, /* s: point */
    DUP,
    PUSHB_1,
      sal_point_max,
    SWAP,
    WS,
  EIF, /* s: point */

  ENDF,

};


/*
 * bci_nibbles
 *
 *   Pop a byte with two delta arguments in its nibbles and push the
 *   expanded arguments separately as two bytes.
 *
 * in: 16 * (end - start) + (start - base)
 *
 * out: start
 *      end
 *
 * sal: sal_base (set to `end' at return)
 */


unsigned char FPGM(bci_nibbles) [] =
{
  PUSHB_1,
    bci_nibbles,
  FDEF,

  DUP,
  PUSHW_1,
    0x04, /* 16*64 */
    0x00,
  DIV, /* s: in hnibble */
  DUP,
  PUSHW_1,
    0x04, /* 16*64 */
    0x00,
  MUL, /* s: in hnibble (hnibble * 16) */
  ROLL,
  SWAP,
  SUB, /* s: hnibble lnibble */

  PUSHB_1,
    sal_base,
  RS,
  ADD, /* s: hnibble start */
  DUP,
  ROLL,
  ADD, /* s: start end */

  DUP,
  PUSHB_1,
    sal_base,
  SWAP,
  WS, /* sal_base = end */

  SWAP,

  ENDF,

};


/*
 * bci_number_set_is_element
 *
 *   Pop values from stack until it is empty.  If one of them is equal to
 *   the current PPEM value, set `cvtl_is_element' to 1 (and to 0
 *   otherwise).
 *
 * in: ppem_value_1
 *     ppem_value_2
 *     ...
 *
 * CVT: cvtl_is_element
 */

unsigned char FPGM(bci_number_set_is_element) [] =
{

  PUSHB_1,
    bci_number_set_is_element,
  FDEF,

/* start_loop: */
  MPPEM,
  EQ,
  IF,
    PUSHB_2,
      cvtl_is_element,
      1,
    WCVTP,
  EIF,

  DEPTH,
  PUSHB_1,
    13,
  NEG,
  SWAP,
  JROT, /* goto start_loop if stack depth != 0 */

  ENDF,

};


/*
 * bci_number_set_is_element2
 *
 *   Pop value ranges from stack until it is empty.  If one of them contains
 *   the current PPEM value, set `cvtl_is_element' to 1 (and to 0
 *   otherwise).
 *
 * in: ppem_range_1_start
 *     ppem_range_1_end
 *     ppem_range_2_start
 *     ppem_range_2_end
 *     ...
 *
 * CVT: cvtl_is_element
 */

unsigned char FPGM(bci_number_set_is_element2) [] =
{

  PUSHB_1,
    bci_number_set_is_element2,
  FDEF,

/* start_loop: */
  MPPEM,
  LTEQ,
  IF,
    MPPEM,
    GTEQ,
    IF,
      PUSHB_2,
        cvtl_is_element,
        1,
      WCVTP,
    EIF,
  ELSE,
    POP,
  EIF,

  DEPTH,
  PUSHB_1,
    19,
  NEG,
  SWAP,
  JROT, /* goto start_loop if stack depth != 0 */

  ENDF,

};


/*
 * bci_create_segment
 *
 *   Store start and end point of a segment in the storage area,
 *   then construct a point in the twilight zone to represent it.
 *
 *   This function is used by `bci_create_segments'.
 *
 * in: start
 *     end
 *       [last (if wrap-around segment)]
 *       [first (if wrap-around segment)]
 *
 * sal: sal_i (start of current segment)
 *      sal_j (current twilight point)
 *      sal_point_min
 *      sal_point_max
 *      sal_base
 *      sal_num_packed_segments
 *
 * CVT: cvtl_scale
 *      cvtl_0x10000
 *      cvtl_temp
 *
 * uses: bci_get_point_extrema
 *       bci_nibbles
 *
 * If `sal_num_packed_segments' is > 0, the start/end pair is stored as
 * delta values in nibbles (without a wrap-around segment).
 */

unsigned char FPGM(bci_create_segment) [] =
{

  PUSHB_1,
    bci_create_segment,
  FDEF,

  PUSHB_2,
    0,
    sal_num_packed_segments,
  RS,
  NEQ,
  IF,
    PUSHB_2,
      sal_num_packed_segments,
      sal_num_packed_segments,
    RS,
    PUSHB_1,
      1,
    SUB,
    WS, /* sal_num_packed_segments = sal_num_packed_segments - 1 */

    PUSHB_1,
      bci_nibbles,
    CALL,
  EIF,

  PUSHB_1,
    sal_i,
  RS,
  PUSHB_1,
    2,
  CINDEX,
  WS, /* sal[sal_i] = start */

  /* initialize inner loop(s) */
  PUSHB_2,
    sal_point_min,
    2,
  CINDEX,
  WS, /* sal_point_min = start */
  PUSHB_2,
    sal_point_max,
    2,
  CINDEX,
  WS, /* sal_point_max = start */

  PUSHB_1,
    1,
  SZPS, /* set zp0, zp1, and zp2 to normal zone 1 */

  SWAP,
  DUP,
  PUSHB_1,
    3,
  CINDEX, /* s: start end end start */
  LT, /* start > end */
  IF,
    /* we have a wrap-around segment with two more arguments */
    /* to give the last and first point of the contour, respectively; */
    /* our job is to store a segment `start'-`last', */
    /* and to get extrema for the two segments */
    /* `start'-`last' and `first'-`end' */

    /* s: first last start end */
    PUSHB_2,
      1,
      sal_i,
    RS,
    ADD,
    PUSHB_1,
      4,
    CINDEX,
    WS, /* sal[sal_i + 1] = last */

    ROLL,
    ROLL, /* s: first end last start */
    DUP,
    ROLL,
    SWAP, /* s: first end start last start */
    SUB, /* s: first end start loop_count */

    PUSHB_1,
      bci_get_point_extrema,
    LOOPCALL,
    /* clean up stack */
    POP,

    SWAP, /* s: end first */
    PUSHB_1,
      1,
    SUB,
    DUP,
    ROLL, /* s: (first - 1) (first - 1) end */
    SWAP,
    SUB, /* s: (first - 1) loop_count */

    PUSHB_1,
      bci_get_point_extrema,
    LOOPCALL,
    /* clean up stack */
    POP,

  ELSE, /* s: start end */
    PUSHB_2,
      1,
      sal_i,
    RS,
    ADD,
    PUSHB_1,
      2,
    CINDEX,
    WS, /* sal[sal_i + 1] = end */

    PUSHB_1,
      2,
    CINDEX,
    SUB, /* s: start loop_count */

    PUSHB_1,
      bci_get_point_extrema,
    LOOPCALL,
    /* clean up stack */
    POP,
  EIF,

  /* the twilight point representing a segment */
  /* is in the middle between the minimum and maximum */
  PUSHB_1,
    sal_point_min,
  RS,
  GC_orig,
  PUSHB_1,
    sal_point_max,
  RS,
  GC_orig,
  ADD,
  PUSHB_1,
    2*64,
  DIV, /* s: middle_pos */

  DO_SCALE, /* middle_pos = middle_pos * scale */

  /* write it to temporary CVT location */
  PUSHB_2,
    cvtl_temp,
    0,
  SZP0, /* set zp0 to twilight zone 0 */
  SWAP,
  WCVTP,

  /* create twilight point with index `sal_j' */
  PUSHB_1,
    sal_j,
  RS,
  PUSHB_1,
    cvtl_temp,
  MIAP_noround,

  PUSHB_3,
    sal_j,
    1,
    sal_j,
  RS,
  ADD, /* twilight_point = twilight_point + 1 */
  WS,

  ENDF,

};


/*
 * bci_create_segments
 *
 *   This is the top-level entry function.
 *
 *   It pops point ranges from the stack to define segments, computes
 *   twilight points to represent segments, and finally calls
 *   `bci_hint_glyph' to handle the rest.
 *
 * in: num_packed_segments
 *     num_segments (N)
 *     segment_start_0
 *     segment_end_0
 *       [contour_last 0 (if wrap-around segment)]
 *       [contour_first 0 (if wrap-around segment)]
 *     segment_start_1
 *     segment_end_1
 *       [contour_last 0 (if wrap-around segment)]
 *       [contour_first 0 (if wrap-around segment)]
 *     ...
 *     segment_start_(N-1)
 *     segment_end_(N-1)
 *       [contour_last (N-1) (if wrap-around segment)]
 *       [contour_first (N-1) (if wrap-around segment)]
 *     ... stuff for bci_hint_glyph ...
 *
 * sal: sal_i (start of current segment)
 *      sal_j (current twilight point)
 *      sal_num_packed_segments
 *      sal_base (the base for delta values in nibbles)
 *
 * CVT: cvtl_is_subglyph
 *
 * uses: bci_create_segment
 *       bci_loop
 *       bci_hint_glyph
 *
 * If `num_packed_segments' is set to p, the first p start/end pairs are
 * stored as delta values in nibbles, with the `start' delta in the lower
 * nibble (and there are no wrap-around segments).  For example, if the
 * first three pairs are 1/3, 5/8, and 12/13, the topmost three bytes on the
 * stack are 0x21, 0x32, and 0x14.
 *
 */

unsigned char FPGM(bci_create_segments) [] =
{

  PUSHB_1,
    bci_create_segments,
  FDEF,

  /* only do something if we are not a subglyph */
  PUSHB_2,
    0,
    cvtl_is_subglyph,
  RCVT,
  EQ,
  IF,
    /* all our measurements are taken along the y axis */
    SVTCA_y,

    PUSHB_1,
      sal_num_packed_segments,
    SWAP,
    WS,

    DUP,
    ADD,
    PUSHB_1,
      1,
    SUB, /* delta = (2*num_segments - 1) */

    PUSHB_6,
      sal_segment_offset,
      sal_segment_offset,

      sal_j,
      0,
      sal_base,
      0,
    WS, /* sal_base = 0 */
    WS, /* sal_j = 0 (point offset) */

    ROLL,
    ADD, /* s: ... sal_segment_offset (sal_segment_offset + delta) */

    PUSHB_2,
      bci_create_segment,
      bci_loop,
    CALL,

    PUSHB_1,
      bci_hint_glyph,
    CALL,

  ELSE,
    CLEAR,
  EIF,

  ENDF,

};


/*
 * bci_create_segments_X
 *
 * Top-level routines for calling `bci_create_segments'.
 */

unsigned char FPGM(bci_create_segments_0) [] =
{

  PUSHB_1,
    bci_create_segments_0,
  FDEF,

  PUSHB_2,
    0,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_1) [] =
{

  PUSHB_1,
    bci_create_segments_1,
  FDEF,

  PUSHB_2,
    1,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_2) [] =
{

  PUSHB_1,
    bci_create_segments_2,
  FDEF,

  PUSHB_2,
    2,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_3) [] =
{

  PUSHB_1,
    bci_create_segments_3,
  FDEF,

  PUSHB_2,
    3,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_4) [] =
{

  PUSHB_1,
    bci_create_segments_4,
  FDEF,

  PUSHB_2,
    4,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_5) [] =
{

  PUSHB_1,
    bci_create_segments_5,
  FDEF,

  PUSHB_2,
    5,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_6) [] =
{

  PUSHB_1,
    bci_create_segments_6,
  FDEF,

  PUSHB_2,
    6,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_7) [] =
{

  PUSHB_1,
    bci_create_segments_7,
  FDEF,

  PUSHB_2,
    7,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_8) [] =
{

  PUSHB_1,
    bci_create_segments_8,
  FDEF,

  PUSHB_2,
    8,
    bci_create_segments,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_9) [] =
{

  PUSHB_1,
    bci_create_segments_9,
  FDEF,

  PUSHB_2,
    9,
    bci_create_segments,
  CALL,

  ENDF,

};


/*
 * bci_create_segments_composite
 *
 *   The same as `bci_create_segments'.
 *   It also decrements the composite component counter.
 *
 * sal: sal_num_packed_segments
 *      sal_segment_offset
 *
 * CVT: cvtl_is_subglyph
 *
 * uses: bci_decrement_component_counter
 *       bci_create_segment
 *       bci_loop
 *       bci_hint_glyph
 */

unsigned char FPGM(bci_create_segments_composite) [] =
{

  PUSHB_1,
    bci_create_segments_composite,
  FDEF,

  PUSHB_1,
    bci_decrement_component_counter,
  CALL,

  /* only do something if we are not a subglyph */
  PUSHB_2,
    0,
    cvtl_is_subglyph,
  RCVT,
  EQ,
  IF,
    /* all our measurements are taken along the y axis */
    SVTCA_y,

    PUSHB_1,
      sal_num_packed_segments,
    SWAP,
    WS,

    DUP,
    ADD,
    PUSHB_1,
      1,
    SUB, /* delta = (2*num_segments - 1) */

    PUSHB_6,
      sal_segment_offset,
      sal_segment_offset,

      sal_j,
      0,
      sal_base,
      0,
    WS, /* sal_base = 0 */
    WS, /* sal_j = 0 (point offset) */

    ROLL,
    ADD, /* s: ... sal_segment_offset (sal_segment_offset + delta) */

    PUSHB_2,
      bci_create_segment,
      bci_loop,
    CALL,

    PUSHB_1,
      bci_hint_glyph,
    CALL,

  ELSE,
    CLEAR,
  EIF,

  ENDF,

};


/*
 * bci_create_segments_composite_X
 *
 * Top-level routines for calling `bci_create_segments_composite'.
 */

unsigned char FPGM(bci_create_segments_composite_0) [] =
{

  PUSHB_1,
    bci_create_segments_composite_0,
  FDEF,

  PUSHB_2,
    0,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_1) [] =
{

  PUSHB_1,
    bci_create_segments_composite_1,
  FDEF,

  PUSHB_2,
    1,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_2) [] =
{

  PUSHB_1,
    bci_create_segments_composite_2,
  FDEF,

  PUSHB_2,
    2,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_3) [] =
{

  PUSHB_1,
    bci_create_segments_composite_3,
  FDEF,

  PUSHB_2,
    3,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_4) [] =
{

  PUSHB_1,
    bci_create_segments_composite_4,
  FDEF,

  PUSHB_2,
    4,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_5) [] =
{

  PUSHB_1,
    bci_create_segments_composite_5,
  FDEF,

  PUSHB_2,
    5,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_6) [] =
{

  PUSHB_1,
    bci_create_segments_composite_6,
  FDEF,

  PUSHB_2,
    6,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_7) [] =
{

  PUSHB_1,
    bci_create_segments_composite_7,
  FDEF,

  PUSHB_2,
    7,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_8) [] =
{

  PUSHB_1,
    bci_create_segments_composite_8,
  FDEF,

  PUSHB_2,
    8,
    bci_create_segments_composite,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_create_segments_composite_9) [] =
{

  PUSHB_1,
    bci_create_segments_composite_9,
  FDEF,

  PUSHB_2,
    9,
    bci_create_segments_composite,
  CALL,

  ENDF,

};


/*
 * bci_align_point
 *
 *   An auxiliary function for `bci_align_segment'.
 *
 * in: point
 *
 * out: point+1
 */

unsigned char FPGM(bci_align_point) [] =
{

  PUSHB_1,
    bci_align_point,
  FDEF,

  DUP,
  ALIGNRP, /* align point with rp0 */

  PUSHB_1,
    1,
  ADD,

  ENDF,

};


/*
 * bci_align_segment
 *
 *   Align all points in a segment to the twilight point in rp0.
 *   zp0 and zp1 must be set to 0 (twilight) and 1 (normal), respectively.
 *
 * in: segment_index
 *
 * sal: sal_segment_offset
 *
 * uses: bci_align_point
 */

unsigned char FPGM(bci_align_segment) [] =
{

  PUSHB_1,
    bci_align_segment,
  FDEF,

  /* we need the values of `sal_segment_offset + 2*segment_index' */
  /* and `sal_segment_offset + 2*segment_index + 1' */
  DUP,
  ADD,
  PUSHB_1,
    sal_segment_offset,
  ADD,
  DUP,
  RS,
  SWAP,
  PUSHB_1,
    1,
  ADD,
  RS, /* s: first last */

  PUSHB_1,
    2,
  CINDEX, /* s: first last first */
  SUB,
  PUSHB_1,
    1,
  ADD, /* s: first loop_count */

  PUSHB_1,
    bci_align_point,
  LOOPCALL,
  /* clean up stack */
  POP,

  ENDF,

};


/*
 * bci_align_segments
 *
 *   Align segments to the twilight point in rp0.
 *   zp0 and zp1 must be set to 0 (twilight) and 1 (normal), respectively.
 *
 * in: first_segment
 *     loop_counter (N)
 *       segment_1
 *       segment_2
 *       ...
 *       segment_N
 *
 * uses: bci_align_segment
 */

unsigned char FPGM(bci_align_segments) [] =
{

  PUSHB_1,
    bci_align_segments,
  FDEF,

  PUSHB_1,
    bci_align_segment,
  CALL,

  PUSHB_1,
    bci_align_segment,
  LOOPCALL,

  ENDF,

};


/*
 * bci_scale_contour
 *
 *   Scale a contour using two points giving the maximum and minimum
 *   coordinates.
 *
 *   It expects that no point on the contour is touched.
 *
 * in: min_point
 *     max_point
 *
 * CVT: cvtl_scale
 *      cvtl_0x10000
 */

unsigned char FPGM(bci_scale_contour) [] =
{

  PUSHB_1,
    bci_scale_contour,
  FDEF,

  DUP,
  DUP,
  GC_orig,
  DUP,
  DO_SCALE, /* min_pos_new = min_pos * scale */
  SWAP,
  SUB,
  SHPIX,

  /* don't scale a single-point contour twice */
  SWAP,
  DUP,
  ROLL,
  NEQ,
  IF,
    DUP,
    GC_orig,
    DUP,
    DO_SCALE, /* max_pos_new = max_pos * scale */
    SWAP,
    SUB,
    SHPIX,

  ELSE,
    POP,
  EIF,

  ENDF,

};


/*
 * bci_scale_glyph
 *
 *   Scale a glyph using a list of points (two points per contour, giving
 *   the maximum and mininum coordinates).
 *
 *   It expects that no point in the glyph is touched.
 *
 *   Note that the point numbers are sorted in ascending order;
 *   `min_point_X' and `max_point_X' thus refer to the two extrema of a
 *   contour without specifying which one is the minimum and maximum.
 *
 * in: num_contours (N)
 *       min_point_1
 *       max_point_1
 *       min_point_2
 *       max_point_2
 *       ...
 *       min_point_N
 *       max_point_N
 *
 * CVT: cvtl_is_subglyph
 *
 * uses: bci_scale_contour
 */

unsigned char FPGM(bci_scale_glyph) [] =
{

  PUSHB_1,
    bci_scale_glyph,
  FDEF,

  /* only do something if we are not a subglyph */
  PUSHB_2,
    0,
    cvtl_is_subglyph,
  RCVT,
  EQ,
  IF,
    /* all our measurements are taken along the y axis */
    SVTCA_y,

    PUSHB_1,
      1,
    SZPS, /* set zp0, zp1, and zp2 to normal zone 1 */

    PUSHB_1,
      bci_scale_contour,
    LOOPCALL,

    PUSHB_1,
      1,
    SZP2, /* set zp2 to normal zone 1 */
    IUP_y,

  ELSE,
    CLEAR,
  EIF,

  ENDF,

};


/*
 * bci_scale_composite_glyph
 *
 *   The same as `bci_scale_glyph'.
 *   It also decrements the composite component counter.
 *
 * CVT: cvtl_is_subglyph
 *
 * uses: bci_decrement_component_counter
 *       bci_scale_contour
 */

unsigned char FPGM(bci_scale_composite_glyph) [] =
{

  PUSHB_1,
    bci_scale_composite_glyph,
  FDEF,

  PUSHB_1,
    bci_decrement_component_counter,
  CALL,

  /* only do something if we are not a subglyph */
  PUSHB_2,
    0,
    cvtl_is_subglyph,
  RCVT,
  EQ,
  IF,
    /* all our measurements are taken along the y axis */
    SVTCA_y,

    PUSHB_1,
      1,
    SZPS, /* set zp0, zp1, and zp2 to normal zone 1 */

    PUSHB_1,
      bci_scale_contour,
    LOOPCALL,

    PUSHB_1,
      1,
    SZP2, /* set zp2 to normal zone 1 */
    IUP_y,

  ELSE,
    CLEAR,
  EIF,

  ENDF,

};


/*
 * bci_shift_contour
 *
 *   Shift a contour by a given amount.
 *
 *   It expects that rp1 (pointed to by zp0) is set up properly; zp2 must
 *   point to the normal zone 1.
 *
 * in: contour
 *
 * out: contour+1
 */

unsigned char FPGM(bci_shift_contour) [] =
{

  PUSHB_1,
    bci_shift_contour,
  FDEF,

  DUP,
  SHC_rp1, /* shift `contour' by (rp1_pos - rp1_orig_pos) */

  PUSHB_1,
    1,
  ADD,

  ENDF,

};


/*
 * bci_shift_subglyph
 *
 *   Shift a subglyph.  To be more specific, it corrects the already applied
 *   subglyph offset (if any) from the `glyf' table which needs to be scaled
 *   also.
 *
 *   If this function is called, a point `x' in the subglyph has been scaled
 *   already (during the hinting of the subglyph itself), and `offset' has
 *   been applied also:
 *
 *     x  ->  x * scale + offset         (1)
 *
 *   However, the offset should be applied first, then the scaling:
 *
 *     x  ->  (x + offset) * scale       (2)
 *
 *   Our job is now to transform (1) to (2); a simple calculation shows that
 *   we have to shift all points of the subglyph by
 *
 *     offset * scale - offset = offset * (scale - 1)
 *
 *   Note that `cvtl_scale' is equal to the above `scale - 1'.
 *
 * in: offset (in FUnits)
 *     num_contours
 *     first_contour
 *
 * CVT: cvtl_funits_to_pixels
 *      cvtl_0x10000
 *      cvtl_scale
 *
 * uses: bci_round
 *       bci_shift_contour
 */

unsigned char FPGM(bci_shift_subglyph) [] =
{

  PUSHB_1,
    bci_shift_subglyph,
  FDEF,

  SVTCA_y,

  PUSHB_1,
    cvtl_funits_to_pixels,
  RCVT, /* scaling factor FUnits -> pixels */
  MUL,
  PUSHB_1,
    cvtl_0x10000,
  RCVT,
  DIV,

  /* the autohinter always rounds offsets */
  PUSHB_1,
    bci_round,
  CALL, /* offset = round(offset) */

  PUSHB_1,
    cvtl_scale,
  RCVT,
  MUL,
  PUSHB_1,
    cvtl_0x10000,
  RCVT,
  DIV, /* delta = offset * (scale - 1) */

  /* and round again */
  PUSHB_1,
    bci_round,
  CALL, /* offset = round(offset) */

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  /* we create twilight point 0 as a reference point, */
  /* setting the original position to zero (using `cvtl_temp') */
  PUSHB_5,
    0,
    0,
    cvtl_temp,
    cvtl_temp,
    0,
  WCVTP,
  MIAP_noround, /* rp0 and rp1 now point to twilight point 0 */

  SWAP, /* s: first_contour num_contours 0 delta */
  SHPIX, /* rp1_pos - rp1_orig_pos = delta */

  PUSHB_2,
    bci_shift_contour,
    1,
  SZP2, /* set zp2 to normal zone 1 */
  LOOPCALL,

  ENDF,

};


/*
 * bci_ip_outer_align_point
 *
 *   Auxiliary function for `bci_action_ip_before' and
 *   `bci_action_ip_after'.
 *
 *   It expects rp0 to contain the edge for alignment, zp0 set to twilight
 *   zone, and both zp1 and zp2 set to normal zone.
 *
 * in: point
 *
 * sal: sal_i (edge_orig_pos)
 *
 * CVT: cvtl_scale
 *      cvtl_0x10000
 */

unsigned char FPGM(bci_ip_outer_align_point) [] =
{

  PUSHB_1,
    bci_ip_outer_align_point,
  FDEF,

  DUP,
  ALIGNRP, /* align `point' with `edge' */
  DUP,
  GC_orig,
  DO_SCALE, /* point_orig_pos = point_orig_pos * scale */

  PUSHB_1,
    sal_i,
  RS,
  SUB, /* s: point (point_orig_pos - edge_orig_pos) */
  SHPIX,

  ENDF,

};


/*
 * bci_ip_on_align_points
 *
 *   Auxiliary function for `bci_action_ip_on'.
 *
 * in: edge (in twilight zone)
 *     loop_counter (N)
 *       point_1
 *       point_2
 *       ...
 *       point_N
 */

unsigned char FPGM(bci_ip_on_align_points) [] =
{

  PUSHB_1,
    bci_ip_on_align_points,
  FDEF,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  SLOOP,
  ALIGNRP,

  ENDF,

};


/*
 * bci_ip_between_align_point
 *
 *   Auxiliary function for `bci_ip_between_align_points'.
 *
 *   It expects rp0 to contain the edge for alignment, zp0 set to twilight
 *   zone, and both zp1 and zp2 set to normal zone.
 *
 * in: point
 *
 * sal: sal_i (edge_orig_pos)
 *      sal_j (stretch_factor)
 *
 * CVT: cvtl_scale
 *      cvtl_0x10000
 */

unsigned char FPGM(bci_ip_between_align_point) [] =
{

  PUSHB_1,
    bci_ip_between_align_point,
  FDEF,

  DUP,
  ALIGNRP, /* align `point' with `edge' */
  DUP,
  GC_orig,
  DO_SCALE, /* point_orig_pos = point_orig_pos * scale */

  PUSHB_1,
    sal_i,
  RS,
  SUB, /* s: point (point_orig_pos - edge_orig_pos) */
  PUSHB_1,
    sal_j,
  RS,
  MUL, /* s: point delta */
  SHPIX,

  ENDF,

};


/*
 * bci_ip_between_align_points
 *
 *   Auxiliary function for `bci_action_ip_between'.
 *
 * in: after_edge (in twilight zone)
 *     before_edge (in twilight zone)
 *     loop_counter (N)
 *       point_1
 *       point_2
 *       ...
 *       point_N
 *
 * sal: sal_i (before_orig_pos)
 *      sal_j (stretch_factor)
 *
 * uses: bci_ip_between_align_point
 */

unsigned char FPGM(bci_ip_between_align_points) [] =
{

  PUSHB_1,
    bci_ip_between_align_points,
  FDEF,

  PUSHB_2,
    2,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */
  CINDEX,
  DUP, /* s: ... before after before before */
  MDAP_noround, /* set rp0 and rp1 to `before' */
  DUP,
  GC_orig, /* s: ... before after before before_orig_pos */
  PUSHB_1,
    sal_i,
  SWAP,
  WS, /* sal_i = before_orig_pos */
  PUSHB_1,
    2,
  CINDEX, /* s: ... before after before after */
  MD_cur, /* a = after_pos - before_pos */
  ROLL,
  ROLL,
  MD_orig_ZP2_0, /* b = after_orig_pos - before_orig_pos */

  DUP,
  IF, /* b != 0 ? */
    DIV, /* s: a/b */
  ELSE,
    POP, /* avoid division by zero */
  EIF,

  PUSHB_1,
    sal_j,
  SWAP,
  WS, /* sal_j = stretch_factor */

  PUSHB_3,
    bci_ip_between_align_point,
    1,
    1,
  SZP2, /* set zp2 to normal zone 1 */
  SZP1, /* set zp1 to normal zone 1 */
  LOOPCALL,

  ENDF,

};


/*
 * bci_action_ip_before
 *
 *   Handle `ip_before' data to align points located before the first edge.
 *
 * in: first_edge (in twilight zone)
 *     loop_counter (N)
 *       point_1
 *       point_2
 *       ...
 *       point_N
 *
 * sal: sal_i (first_edge_orig_pos)
 *
 * uses: bci_ip_outer_align_point
 */

unsigned char FPGM(bci_action_ip_before) [] =
{

  PUSHB_1,
    bci_action_ip_before,
  FDEF,

  PUSHB_1,
    0,
  SZP2, /* set zp2 to twilight zone 0 */

  DUP,
  GC_orig,
  PUSHB_1,
    sal_i,
  SWAP,
  WS, /* sal_i = first_edge_orig_pos */

  PUSHB_3,
    0,
    1,
    1,
  SZP2, /* set zp2 to normal zone 1 */
  SZP1, /* set zp1 to normal zone 1 */
  SZP0, /* set zp0 to twilight zone 0 */

  MDAP_noround, /* set rp0 and rp1 to `first_edge' */

  PUSHB_1,
    bci_ip_outer_align_point,
  LOOPCALL,

  ENDF,

};


/*
 * bci_action_ip_after
 *
 *   Handle `ip_after' data to align points located after the last edge.
 *
 * in: last_edge (in twilight zone)
 *     loop_counter (N)
 *       point_1
 *       point_2
 *       ...
 *       point_N
 *
 * sal: sal_i (last_edge_orig_pos)
 *
 * uses: bci_ip_outer_align_point
 */

unsigned char FPGM(bci_action_ip_after) [] =
{

  PUSHB_1,
    bci_action_ip_after,
  FDEF,

  PUSHB_1,
    0,
  SZP2, /* set zp2 to twilight zone 0 */

  DUP,
  GC_orig,
  PUSHB_1,
    sal_i,
  SWAP,
  WS, /* sal_i = last_edge_orig_pos */

  PUSHB_3,
    0,
    1,
    1,
  SZP2, /* set zp2 to normal zone 1 */
  SZP1, /* set zp1 to normal zone 1 */
  SZP0, /* set zp0 to twilight zone 0 */

  MDAP_noround, /* set rp0 and rp1 to `last_edge' */

  PUSHB_1,
    bci_ip_outer_align_point,
  LOOPCALL,

  ENDF,

};


/*
 * bci_action_ip_on
 *
 *   Handle `ip_on' data to align points located on an edge coordinate (but
 *   not part of an edge).
 *
 * in: loop_counter (M)
 *       edge_1 (in twilight zone)
 *       loop_counter (N_1)
 *         point_1
 *         point_2
 *         ...
 *         point_N_1
 *       edge_2 (in twilight zone)
 *       loop_counter (N_2)
 *         point_1
 *         point_2
 *         ...
 *         point_N_2
 *       ...
 *       edge_M (in twilight zone)
 *       loop_counter (N_M)
 *         point_1
 *         point_2
 *         ...
 *         point_N_M
 *
 * uses: bci_ip_on_align_points
 */

unsigned char FPGM(bci_action_ip_on) [] =
{

  PUSHB_1,
    bci_action_ip_on,
  FDEF,

  PUSHB_2,
    0,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  SZP0, /* set zp0 to twilight zone 0 */

  PUSHB_1,
    bci_ip_on_align_points,
  LOOPCALL,

  ENDF,

};


/*
 * bci_action_ip_between
 *
 *   Handle `ip_between' data to align points located between two edges.
 *
 * in: loop_counter (M)
 *       before_edge_1 (in twilight zone)
 *       after_edge_1 (in twilight zone)
 *       loop_counter (N_1)
 *         point_1
 *         point_2
 *         ...
 *         point_N_1
 *       before_edge_2 (in twilight zone)
 *       after_edge_2 (in twilight zone)
 *       loop_counter (N_2)
 *         point_1
 *         point_2
 *         ...
 *         point_N_2
 *       ...
 *       before_edge_M (in twilight zone)
 *       after_edge_M (in twilight zone)
 *       loop_counter (N_M)
 *         point_1
 *         point_2
 *         ...
 *         point_N_M
 *
 * uses: bci_ip_between_align_points
 */

unsigned char FPGM(bci_action_ip_between) [] =
{

  PUSHB_1,
    bci_action_ip_between,
  FDEF,

  PUSHB_1,
    bci_ip_between_align_points,
  LOOPCALL,

  ENDF,

};


/*
 * bci_adjust_common
 *
 *   Common code for bci_action_adjust routines.
 *
 * uses: func[cvtl_stem_width_function]
 */

unsigned char FPGM(bci_adjust_common) [] =
{

  PUSHB_1,
    bci_adjust_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    4,
  CINDEX, /* s: [...] edge2 edge is_round is_serif edge2 */
  PUSHB_1,
    4,
  CINDEX, /* s: [...] edge2 edge is_round is_serif edge2 edge */
  MD_orig_ZP2_0, /* s: [...] edge2 edge is_round is_serif org_len */

  PUSHB_1,
    cvtl_stem_width_function,
  RCVT,
  CALL,
  NEG, /* s: [...] edge2 edge -cur_len */

  ROLL, /* s: [...] edge -cur_len edge2 */
  MDAP_noround, /* set rp0 and rp1 to `edge2' */
  SWAP,
  DUP,
  DUP, /* s: [...] -cur_len edge edge edge */
  ALIGNRP, /* align `edge' with `edge2' */
  ROLL,
  SHPIX, /* shift `edge' by -cur_len */

  ENDF,

};


/*
 * bci_adjust_bound
 *
 *   Handle the ADJUST_BOUND action to align an edge of a stem if the other
 *   edge of the stem has already been moved, then moving it again if
 *   necessary to stay bound.
 *
 * in: edge2_is_serif
 *     edge_is_round
 *     edge_point (in twilight zone)
 *     edge2_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_adjust_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_adjust_bound) [] =
{

  PUSHB_1,
    bci_adjust_bound,
  FDEF,

  PUSHB_1,
    bci_adjust_common,
  CALL,

  SWAP, /* s: edge edge[-1] */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `edge[-1]' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: edge edge[-1]_pos edge_pos */
  GT, /* edge_pos < edge[-1]_pos */
  IF,
    DUP,
    ALIGNRP, /* align `edge' to `edge[-1]' */
  EIF,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_adjust_bound
 * bci_action_adjust_bound_serif
 * bci_action_adjust_bound_round
 * bci_action_adjust_bound_round_serif
 *
 * Higher-level routines for calling `bci_adjust_bound'.
 */

unsigned char FPGM(bci_action_adjust_bound) [] =
{

  PUSHB_1,
    bci_action_adjust_bound,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_adjust_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_bound_serif) [] =
{

  PUSHB_1,
    bci_action_adjust_bound_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_adjust_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_bound_round) [] =
{

  PUSHB_1,
    bci_action_adjust_bound_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_adjust_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_bound_round_serif) [] =
{

  PUSHB_1,
    bci_action_adjust_bound_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_adjust_bound,
  CALL,

  ENDF,

};


/*
 * bci_adjust
 *
 *   Handle the ADJUST action to align an edge of a stem if the other edge
 *   of the stem has already been moved.
 *
 * in: edge2_is_serif
 *     edge_is_round
 *     edge_point (in twilight zone)
 *     edge2_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_adjust_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_adjust) [] =
{

  PUSHB_1,
    bci_adjust,
  FDEF,

  PUSHB_1,
    bci_adjust_common,
  CALL,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_adjust
 * bci_action_adjust_serif
 * bci_action_adjust_round
 * bci_action_adjust_round_serif
 *
 * Higher-level routines for calling `bci_adjust'.
 */

unsigned char FPGM(bci_action_adjust) [] =
{

  PUSHB_1,
    bci_action_adjust,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_adjust,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_serif) [] =
{

  PUSHB_1,
    bci_action_adjust_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_adjust,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_round) [] =
{

  PUSHB_1,
    bci_action_adjust_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_adjust,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_adjust_round_serif) [] =
{

  PUSHB_1,
    bci_action_adjust_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_adjust,
  CALL,

  ENDF,

};


/*
 * bci_stem_common
 *
 *   Common code for bci_action_stem routines.
 *
 * sal: sal_anchor
 *      sal_temp1
 *      sal_temp2
 *      sal_temp3
 *
 * uses: func[cvtl_stem_width_function]
 *       bci_round
 */

#undef sal_u_off
#define sal_u_off sal_temp1
#undef sal_d_off
#define sal_d_off sal_temp2
#undef sal_org_len
#define sal_org_len sal_temp3
#undef sal_edge2
#define sal_edge2 sal_temp3

unsigned char FPGM(bci_stem_common) [] =
{

  PUSHB_1,
    bci_stem_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    4,
  CINDEX,
  PUSHB_1,
    4,
  CINDEX,
  DUP, /* s: [...] edge2 edge is_round is_serif edge2 edge edge */
  MDAP_noround, /* set rp0 and rp1 to `edge_point' (for ALIGNRP below) */

  MD_orig_ZP2_0, /* s: [...] edge2 edge is_round is_serif org_len */
  DUP,
  PUSHB_1,
    sal_org_len,
  SWAP,
  WS,

  PUSHB_1,
    cvtl_stem_width_function,
  RCVT,
  CALL, /* s: [...] edge2 edge cur_len */

  DUP,
  PUSHB_1,
    96,
  LT, /* cur_len < 96 */
  IF,
    DUP,
    PUSHB_1,
      64,
    LTEQ, /* cur_len <= 64 */
    IF,
      PUSHB_4,
        sal_u_off,
        32,
        sal_d_off,
        32,

    ELSE,
      PUSHB_4,
        sal_u_off,
        38,
        sal_d_off,
        26,
    EIF,
    WS,
    WS,

    SWAP, /* s: [...] edge2 cur_len edge */
    DUP,
    PUSHB_1,
      sal_anchor,
    RS,
    DUP, /* s: [...] edge2 cur_len edge edge anchor anchor */
    ROLL,
    SWAP,
    MD_orig_ZP2_0,
    SWAP,
    GC_cur,
    ADD, /* s: [...] edge2 cur_len edge org_pos */
    PUSHB_1,
      sal_org_len,
    RS,
    PUSHB_1,
      2*64,
    DIV,
    ADD, /* s: [...] edge2 cur_len edge org_center */

    DUP,
    PUSHB_1,
      bci_round,
    CALL, /* s: [...] edge2 cur_len edge org_center cur_pos1 */

    DUP,
    ROLL,
    ROLL,
    SUB, /* s: ... cur_len edge cur_pos1 (org_center - cur_pos1) */

    DUP,
    PUSHB_1,
      sal_u_off,
    RS,
    ADD,
    ABS, /* s: ... cur_len edge cur_pos1 (org_center - cur_pos1) delta1 */

    SWAP,
    PUSHB_1,
      sal_d_off,
    RS,
    SUB,
    ABS, /* s: [...] edge2 cur_len edge cur_pos1 delta1 delta2 */

    LT, /* delta1 < delta2 */
    IF,
      PUSHB_1,
        sal_u_off,
      RS,
      SUB, /* cur_pos1 = cur_pos1 - u_off */

    ELSE,
      PUSHB_1,
        sal_d_off,
      RS,
      ADD, /* cur_pos1 = cur_pos1 + d_off */
    EIF, /* s: [...] edge2 cur_len edge cur_pos1 */

    PUSHB_1,
      3,
    CINDEX,
    PUSHB_1,
      2*64,
    DIV,
    SUB, /* arg = cur_pos1 - cur_len/2 */

    SWAP, /* s: [...] edge2 cur_len arg edge */
    DUP,
    DUP,
    PUSHB_1,
      4,
    MINDEX,
    SWAP, /* s: [...] edge2 cur_len edge edge arg edge */
    GC_cur,
    SUB,
    SHPIX, /* edge = cur_pos1 - cur_len/2 */

  ELSE,
    SWAP, /* s: [...] edge2 cur_len edge */
    PUSHB_1,
      sal_anchor,
    RS,
    GC_cur, /* s: [...] edge2 cur_len edge anchor_pos */
    PUSHB_1,
      2,
    CINDEX,
    PUSHB_1,
      sal_anchor,
    RS,
    MD_orig_ZP2_0,
    ADD, /* s: [...] edge2 cur_len edge org_pos */

    DUP,
    PUSHB_1,
      sal_org_len,
    RS,
    PUSHB_1,
      2*64,
    DIV,
    ADD, /* s: [...] edge2 cur_len edge org_pos org_center */

    SWAP,
    DUP,
    PUSHB_1,
      bci_round,
    CALL, /* cur_pos1 = ROUND(org_pos) */
    SWAP,
    PUSHB_1,
      sal_org_len,
    RS,
    ADD,
    PUSHB_1,
      bci_round,
    CALL,
    PUSHB_1,
      5,
    CINDEX,
    SUB, /* s: [...] edge2 cur_len edge org_center cur_pos1 cur_pos2 */

    PUSHB_1,
      5,
    CINDEX,
    PUSHB_1,
      2*64,
    DIV,
    PUSHB_1,
      4,
    MINDEX,
    SUB, /* s: ... cur_len edge cur_pos1 cur_pos2 (cur_len/2 - org_center) */

    DUP,
    PUSHB_1,
      4,
    CINDEX,
    ADD,
    ABS, /* delta1 = ABS(cur_pos1 + cur_len / 2 - org_center) */
    SWAP,
    PUSHB_1,
      3,
    CINDEX,
    ADD,
    ABS, /* s: ... edge2 cur_len edge cur_pos1 cur_pos2 delta1 delta2 */
    LT, /* delta1 < delta2 */
    IF,
      POP, /* arg = cur_pos1 */

    ELSE,
      SWAP,
      POP, /* arg = cur_pos2 */
    EIF, /* s: [...] edge2 cur_len edge arg */
    SWAP,
    DUP,
    DUP,
    PUSHB_1,
      4,
    MINDEX,
    SWAP, /* s: [...] edge2 cur_len edge edge arg edge */
    GC_cur,
    SUB,
    SHPIX, /* edge = arg */
  EIF, /* s: [...] edge2 cur_len edge */

  ENDF,

};


/*
 * bci_stem_bound
 *
 *   Handle the STEM action to align two edges of a stem, then moving one
 *   edge again if necessary to stay bound.
 *
 *   The code after computing `cur_len' to shift `edge' and `edge2'
 *   is equivalent to the snippet below (part of `ta_latin_hint_edges'):
 *
 *      if cur_len < 96:
 *        if cur_len < = 64:
 *          u_off = 32
 *          d_off = 32
 *        else:
 *          u_off = 38
 *          d_off = 26
 *
 *        org_pos = anchor + (edge_orig - anchor_orig);
 *        org_center = org_pos + org_len / 2;
 *
 *        cur_pos1 = ROUND(org_center)
 *        delta1 = ABS(org_center - (cur_pos1 - u_off))
 *        delta2 = ABS(org_center - (cur_pos1 + d_off))
 *        if (delta1 < delta2):
 *          cur_pos1 = cur_pos1 - u_off
 *        else:
 *          cur_pos1 = cur_pos1 + d_off
 *
 *        edge = cur_pos1 - cur_len / 2
 *
 *      else:
 *        org_pos = anchor + (edge_orig - anchor_orig)
 *        org_center = org_pos + org_len / 2;
 *
 *        cur_pos1 = ROUND(org_pos)
 *        delta1 = ABS(cur_pos1 + cur_len / 2 - org_center)
 *        cur_pos2 = ROUND(org_pos + org_len) - cur_len
 *        delta2 = ABS(cur_pos2 + cur_len / 2 - org_center)
 *
 *        if (delta1 < delta2):
 *          edge = cur_pos1
 *        else:
 *          edge = cur_pos2
 *
 *      edge2 = edge + cur_len
 *
 * in: edge2_is_serif
 *     edge_is_round
 *     edge_point (in twilight zone)
 *     edge2_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *     ... stuff for bci_align_segments (edge2)...
 *
 * sal: sal_anchor
 *      sal_temp1
 *      sal_temp2
 *      sal_temp3
 *
 * uses: bci_stem_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_stem_bound) [] =
{

  PUSHB_1,
    bci_stem_bound,
  FDEF,

  PUSHB_1,
    bci_stem_common,
  CALL,

  ROLL, /* s: edge[-1] cur_len edge edge2 */
  DUP,
  DUP,
  ALIGNRP, /* align `edge2' with rp0 (still `edge') */
  PUSHB_1,
    sal_edge2,
  SWAP,
  WS, /* s: edge[-1] cur_len edge edge2 */
  ROLL,
  SHPIX, /* edge2 = edge + cur_len */

  SWAP, /* s: edge edge[-1] */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `edge[-1]' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: edge edge[-1]_pos edge_pos */
  GT, /* edge_pos < edge[-1]_pos */
  IF,
    DUP,
    ALIGNRP, /* align `edge' to `edge[-1]' */
  EIF,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  PUSHB_1,
    sal_edge2,
  RS,
  MDAP_noround, /* set rp0 and rp1 to `edge2' */

  PUSHB_1,
    bci_align_segments,
  CALL,

  ENDF,

};


/*
 * bci_action_stem_bound
 * bci_action_stem_bound_serif
 * bci_action_stem_bound_round
 * bci_action_stem_bound_round_serif
 *
 * Higher-level routines for calling `bci_stem_bound'.
 */

unsigned char FPGM(bci_action_stem_bound) [] =
{

  PUSHB_1,
    bci_action_stem_bound,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_stem_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_bound_serif) [] =
{

  PUSHB_1,
    bci_action_stem_bound_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_stem_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_bound_round) [] =
{

  PUSHB_1,
    bci_action_stem_bound_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_stem_bound,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_bound_round_serif) [] =
{

  PUSHB_1,
    bci_action_stem_bound_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_stem_bound,
  CALL,

  ENDF,

};


/*
 * bci_stem
 *
 *   Handle the STEM action to align two edges of a stem.
 *
 *   See `bci_stem_bound' for more details.
 *
 * in: edge2_is_serif
 *     edge_is_round
 *     edge_point (in twilight zone)
 *     edge2_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *     ... stuff for bci_align_segments (edge2)...
 *
 * sal: sal_anchor
 *      sal_temp1
 *      sal_temp2
 *      sal_temp3
 *
 * uses: bci_stem_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_stem) [] =
{

  PUSHB_1,
    bci_stem,
  FDEF,

  PUSHB_1,
    bci_stem_common,
  CALL,

  POP,
  SWAP, /* s: cur_len edge2 */
  DUP,
  DUP,
  ALIGNRP, /* align `edge2' with rp0 (still `edge') */
  PUSHB_1,
    sal_edge2,
  SWAP,
  WS, /* s: cur_len edge2 */
  SWAP,
  SHPIX, /* edge2 = edge + cur_len */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  PUSHB_1,
    sal_edge2,
  RS,
  MDAP_noround, /* set rp0 and rp1 to `edge2' */

  PUSHB_1,
    bci_align_segments,
  CALL,
  ENDF,

};


/*
 * bci_action_stem
 * bci_action_stem_serif
 * bci_action_stem_round
 * bci_action_stem_round_serif
 *
 * Higher-level routines for calling `bci_stem'.
 */

unsigned char FPGM(bci_action_stem) [] =
{

  PUSHB_1,
    bci_action_stem,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_stem,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_serif) [] =
{

  PUSHB_1,
    bci_action_stem_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_stem,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_round) [] =
{

  PUSHB_1,
    bci_action_stem_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_stem,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_stem_round_serif) [] =
{

  PUSHB_1,
    bci_action_stem_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_stem,
  CALL,

  ENDF,

};


/*
 * bci_link
 *
 *   Handle the LINK action to link an edge to another one.
 *
 * in: stem_is_serif
 *     base_is_round
 *     base_point (in twilight zone)
 *     stem_point (in twilight zone)
 *     ... stuff for bci_align_segments (base) ...
 *
 * uses: func[cvtl_stem_width_function]
 *       bci_align_segments
 */

unsigned char FPGM(bci_link) [] =
{

  PUSHB_1,
    bci_link,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    4,
  CINDEX,
  PUSHB_1,
    4,
  MINDEX,
  DUP, /* s: stem is_round is_serif stem base base */
  MDAP_noround, /* set rp0 and rp1 to `base_point' (for ALIGNRP below) */

  MD_orig_ZP2_0, /* s: stem is_round is_serif dist_orig */

  PUSHB_1,
    cvtl_stem_width_function,
  RCVT,
  CALL, /* s: stem new_dist */

  SWAP,
  DUP,
  ALIGNRP, /* align `stem_point' with `base_point' */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `stem_point' */
  SWAP,
  SHPIX, /* stem_point = base_point + new_dist */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_link
 * bci_action_link_serif
 * bci_action_link_round
 * bci_action_link_round_serif
 *
 * Higher-level routines for calling `bci_link'.
 */

unsigned char FPGM(bci_action_link) [] =
{

  PUSHB_1,
    bci_action_link,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_link,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_link_serif) [] =
{

  PUSHB_1,
    bci_action_link_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_link,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_link_round) [] =
{

  PUSHB_1,
    bci_action_link_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_link,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_link_round_serif) [] =
{

  PUSHB_1,
    bci_action_link_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_link,
  CALL,

  ENDF,

};


/*
 * bci_anchor
 *
 *   Handle the ANCHOR action to align two edges
 *   and to set the edge anchor.
 *
 *   The code after computing `cur_len' to shift `edge' and `edge2'
 *   is equivalent to the snippet below (part of `ta_latin_hint_edges'):
 *
 *      if cur_len < 96:
 *        if cur_len < = 64:
 *          u_off = 32
 *          d_off = 32
 *        else:
 *          u_off = 38
 *          d_off = 26
 *
 *        org_center = edge_orig + org_len / 2
 *        cur_pos1 = ROUND(org_center)
 *
 *        error1 = ABS(org_center - (cur_pos1 - u_off))
 *        error2 = ABS(org_center - (cur_pos1 + d_off))
 *        if (error1 < error2):
 *          cur_pos1 = cur_pos1 - u_off
 *        else:
 *          cur_pos1 = cur_pos1 + d_off
 *
 *        edge = cur_pos1 - cur_len / 2
 *        edge2 = edge + cur_len
 *
 *      else:
 *        edge = ROUND(edge_orig)
 *
 * in: edge2_is_serif
 *     edge_is_round
 *     edge_point (in twilight zone)
 *     edge2_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * sal: sal_anchor
 *      sal_temp1
 *      sal_temp2
 *      sal_temp3
 *
 * uses: func[cvtl_stem_width_function]
 *       bci_round
 *       bci_align_segments
 */

#undef sal_u_off
#define sal_u_off sal_temp1
#undef sal_d_off
#define sal_d_off sal_temp2
#undef sal_org_len
#define sal_org_len sal_temp3

unsigned char FPGM(bci_anchor) [] =
{

  PUSHB_1,
    bci_anchor,
  FDEF,

  /* store anchor point number in `sal_anchor' */
  PUSHB_2,
    sal_anchor,
    4,
  CINDEX,
  WS, /* sal_anchor = edge_point */

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    4,
  CINDEX,
  PUSHB_1,
    4,
  CINDEX,
  DUP, /* s: edge2 edge is_round is_serif edge2 edge edge */
  MDAP_noround, /* set rp0 and rp1 to `edge_point' (for ALIGNRP below) */

  MD_orig_ZP2_0, /* s: edge2 edge is_round is_serif org_len */
  DUP,
  PUSHB_1,
    sal_org_len,
  SWAP,
  WS,

  PUSHB_1,
    cvtl_stem_width_function,
  RCVT,
  CALL, /* s: edge2 edge cur_len */

  DUP,
  PUSHB_1,
    96,
  LT, /* cur_len < 96 */
  IF,
    DUP,
    PUSHB_1,
      64,
    LTEQ, /* cur_len <= 64 */
    IF,
      PUSHB_4,
        sal_u_off,
        32,
        sal_d_off,
        32,

    ELSE,
      PUSHB_4,
        sal_u_off,
        38,
        sal_d_off,
        26,
    EIF,
    WS,
    WS,

    SWAP, /* s: edge2 cur_len edge */
    DUP, /* s: edge2 cur_len edge edge */

    GC_orig,
    PUSHB_1,
      sal_org_len,
    RS,
    PUSHB_1,
      2*64,
    DIV,
    ADD, /* s: edge2 cur_len edge org_center */

    DUP,
    PUSHB_1,
      bci_round,
    CALL, /* s: edge2 cur_len edge org_center cur_pos1 */

    DUP,
    ROLL,
    ROLL,
    SUB, /* s: edge2 cur_len edge cur_pos1 (org_center - cur_pos1) */

    DUP,
    PUSHB_1,
      sal_u_off,
    RS,
    ADD,
    ABS, /* s: edge2 cur_len edge cur_pos1 (org_center - cur_pos1) error1 */

    SWAP,
    PUSHB_1,
      sal_d_off,
    RS,
    SUB,
    ABS, /* s: edge2 cur_len edge cur_pos1 error1 error2 */

    LT, /* error1 < error2 */
    IF,
      PUSHB_1,
        sal_u_off,
      RS,
      SUB, /* cur_pos1 = cur_pos1 - u_off */

    ELSE,
      PUSHB_1,
        sal_d_off,
      RS,
      ADD, /* cur_pos1 = cur_pos1 + d_off */
    EIF, /* s: edge2 cur_len edge cur_pos1 */

    PUSHB_1,
      3,
    CINDEX,
    PUSHB_1,
      2*64,
    DIV,
    SUB, /* s: edge2 cur_len edge (cur_pos1 - cur_len/2) */

    PUSHB_1,
      2,
    CINDEX, /* s: edge2 cur_len edge (cur_pos1 - cur_len/2) edge */
    GC_cur,
    SUB,
    SHPIX, /* edge = cur_pos1 - cur_len/2 */

    SWAP, /* s: cur_len edge2 */
    DUP,
    ALIGNRP, /* align `edge2' with rp0 (still `edge') */
    SWAP,
    SHPIX, /* edge2 = edge1 + cur_len */

  ELSE,
    POP, /* s: edge2 edge */
    DUP,
    DUP,
    GC_cur,
    SWAP,
    GC_orig,
    PUSHB_1,
      bci_round,
    CALL, /* s: edge2 edge edge_pos round(edge_orig_pos) */
    SWAP,
    SUB,
    SHPIX, /* edge = round(edge_orig) */

    /* clean up stack */
    POP,
  EIF,

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_anchor
 * bci_action_anchor_serif
 * bci_action_anchor_round
 * bci_action_anchor_round_serif
 *
 * Higher-level routines for calling `bci_anchor'.
 */

unsigned char FPGM(bci_action_anchor) [] =
{

  PUSHB_1,
    bci_action_anchor,
  FDEF,

  PUSHB_3,
    0,
    0,
    bci_anchor,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_anchor_serif) [] =
{

  PUSHB_1,
    bci_action_anchor_serif,
  FDEF,

  PUSHB_3,
    0,
    1,
    bci_anchor,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_anchor_round) [] =
{

  PUSHB_1,
    bci_action_anchor_round,
  FDEF,

  PUSHB_3,
    1,
    0,
    bci_anchor,
  CALL,

  ENDF,

};

unsigned char FPGM(bci_action_anchor_round_serif) [] =
{

  PUSHB_1,
    bci_action_anchor_round_serif,
  FDEF,

  PUSHB_3,
    1,
    1,
    bci_anchor,
  CALL,

  ENDF,

};


/*
 * bci_action_blue_anchor
 *
 *   Handle the BLUE_ANCHOR action to align an edge with a blue zone
 *   and to set the edge anchor.
 *
 * in: anchor_point (in twilight zone)
 *     blue_cvt_idx
 *     edge_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * sal: sal_anchor
 *
 * uses: bci_action_blue
 */

unsigned char FPGM(bci_action_blue_anchor) [] =
{

  PUSHB_1,
    bci_action_blue_anchor,
  FDEF,

  /* store anchor point number in `sal_anchor' */
  PUSHB_1,
    sal_anchor,
  SWAP,
  WS,

  PUSHB_1,
    bci_action_blue,
  CALL,

  ENDF,

};


/*
 * bci_action_blue
 *
 *   Handle the BLUE action to align an edge with a blue zone.
 *
 * in: blue_cvt_idx
 *     edge_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_align_segments
 */

unsigned char FPGM(bci_action_blue) [] =
{

  PUSHB_1,
    bci_action_blue,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  /* move `edge_point' to `blue_cvt_idx' position; */
  /* note that we can't use MIAP since this would modify */
  /* the twilight point's original coordinates also */
  RCVT,
  SWAP,
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `edge' */
  DUP,
  GC_cur, /* s: new_pos edge edge_pos */
  ROLL,
  SWAP,
  SUB, /* s: edge (new_pos - edge_pos) */
  SHPIX,

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_serif_common
 *
 *   Common code for bci_action_serif routines.
 */

unsigned char FPGM(bci_serif_common) [] =
{

  PUSHB_1,
    bci_serif_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  DUP,
  DUP,
  DUP,
  PUSHB_1,
    5,
  MINDEX, /* s: [...] serif serif serif serif base */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `base_point' */
  MD_orig_ZP2_0,
  SWAP,
  ALIGNRP, /* align `serif_point' with `base_point' */
  SHPIX, /* serif = base + (serif_orig_pos - base_orig_pos) */

  ENDF,

};


/*
 * bci_lower_bound
 *
 *   Move an edge if necessary to stay within a lower bound.
 *
 * in: edge
 *     bound
 *
 * uses: bci_align_segments
 */

unsigned char FPGM(bci_lower_bound) [] =
{

  PUSHB_1,
    bci_lower_bound,
  FDEF,

  SWAP, /* s: edge bound */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `bound' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: edge bound_pos edge_pos */
  GT, /* edge_pos < bound_pos */
  IF,
    DUP,
    ALIGNRP, /* align `edge' to `bound' */
  EIF,

  MDAP_noround, /* set rp0 and rp1 to `edge_point' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_upper_bound
 *
 *   Move an edge if necessary to stay within an upper bound.
 *
 * in: edge
 *     bound
 *
 * uses: bci_align_segments
 */

unsigned char FPGM(bci_upper_bound) [] =
{

  PUSHB_1,
    bci_upper_bound,
  FDEF,

  SWAP, /* s: edge bound */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `bound' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: edge bound_pos edge_pos */
  LT, /* edge_pos > bound_pos */
  IF,
    DUP,
    ALIGNRP, /* align `edge' to `bound' */
  EIF,

  MDAP_noround, /* set rp0 and rp1 to `edge_point' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_upper_lower_bound
 *
 *   Move an edge if necessary to stay within a lower and lower bound.
 *
 * in: edge
 *     lower
 *     upper
 *
 * uses: bci_align_segments
 */

unsigned char FPGM(bci_upper_lower_bound) [] =
{

  PUSHB_1,
    bci_upper_lower_bound,
  FDEF,

  SWAP, /* s: upper serif lower */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `lower' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: upper serif lower_pos serif_pos */
  GT, /* serif_pos < lower_pos */
  IF,
    DUP,
    ALIGNRP, /* align `serif' to `lower' */
  EIF,

  SWAP, /* s: serif upper */
  DUP,
  MDAP_noround, /* set rp0 and rp1 to `upper' */
  GC_cur,
  PUSHB_1,
    2,
  CINDEX,
  GC_cur, /* s: serif upper_pos serif_pos */
  LT, /* serif_pos > upper_pos */
  IF,
    DUP,
    ALIGNRP, /* align `serif' to `upper' */
  EIF,

  MDAP_noround, /* set rp0 and rp1 to `serif_point' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_serif
 *
 *   Handle the SERIF action to align a serif with its base.
 *
 * in: serif_point (in twilight zone)
 *     base_point (in twilight zone)
 *     ... stuff for bci_align_segments (serif) ...
 *
 * uses: bci_serif_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_action_serif) [] =
{

  PUSHB_1,
    bci_action_serif,
  FDEF,

  PUSHB_1,
    bci_serif_common,
  CALL,

  MDAP_noround, /* set rp0 and rp1 to `serif_point' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_serif_lower_bound
 *
 *   Handle the SERIF action to align a serif with its base, then moving it
 *   again if necessary to stay within a lower bound.
 *
 * in: serif_point (in twilight zone)
 *     base_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (serif) ...
 *
 * uses: bci_serif_common
 *       bci_lower_bound
 */

unsigned char FPGM(bci_action_serif_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_common,
  CALL,

  PUSHB_1,
    bci_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_upper_bound
 *
 *   Handle the SERIF action to align a serif with its base, then moving it
 *   again if necessary to stay within an upper bound.
 *
 * in: serif_point (in twilight zone)
 *     base_point (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (serif) ...
 *
 * uses: bci_serif_common
 *       bci_upper_bound
 */

unsigned char FPGM(bci_action_serif_upper_bound) [] =
{

  PUSHB_1,
    bci_action_serif_upper_bound,
  FDEF,

  PUSHB_1,
    bci_serif_common,
  CALL,

  PUSHB_1,
    bci_upper_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_upper_lower_bound
 *
 *   Handle the SERIF action to align a serif with its base, then moving it
 *   again if necessary to stay within a lower and upper bound.
 *
 * in: serif_point (in twilight zone)
 *     base_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (serif) ...
 *
 * uses: bci_serif_common
 *       bci_upper_lower_bound
 */

unsigned char FPGM(bci_action_serif_upper_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_upper_lower_bound,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    bci_serif_common,
  CALL,

  PUSHB_1,
    bci_upper_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_serif_anchor_common
 *
 *   Common code for bci_action_serif_anchor routines.
 *
 * sal: sal_anchor
 *
 * uses: bci_round
 */

unsigned char FPGM(bci_serif_anchor_common) [] =
{

  PUSHB_1,
    bci_serif_anchor_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  DUP,
  PUSHB_1,
    sal_anchor,
  SWAP,
  WS, /* sal_anchor = edge_point */

  DUP,
  DUP,
  DUP,
  GC_cur,
  SWAP,
  GC_orig,
  PUSHB_1,
    bci_round,
  CALL, /* s: [...] edge edge edge_pos round(edge_orig_pos) */
  SWAP,
  SUB,
  SHPIX, /* edge = round(edge_orig) */

  ENDF,

};


/*
 * bci_action_serif_anchor
 *
 *   Handle the SERIF_ANCHOR action to align a serif and to set the edge
 *   anchor.
 *
 * in: edge_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_anchor_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_action_serif_anchor) [] =
{

  PUSHB_1,
    bci_action_serif_anchor,
  FDEF,

  PUSHB_1,
    bci_serif_anchor_common,
  CALL,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_serif_anchor_lower_bound
 *
 *   Handle the SERIF_ANCHOR action to align a serif and to set the edge
 *   anchor, then moving it again if necessary to stay within a lower
 *   bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_anchor_common
 *       bci_lower_bound
 */

unsigned char FPGM(bci_action_serif_anchor_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_anchor_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_anchor_common,
  CALL,

  PUSHB_1,
    bci_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_anchor_upper_bound
 *
 *   Handle the SERIF_ANCHOR action to align a serif and to set the edge
 *   anchor, then moving it again if necessary to stay within an upper
 *   bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_anchor_common
 *       bci_upper_bound
 */

unsigned char FPGM(bci_action_serif_anchor_upper_bound) [] =
{

  PUSHB_1,
    bci_action_serif_anchor_upper_bound,
  FDEF,

  PUSHB_1,
    bci_serif_anchor_common,
  CALL,

  PUSHB_1,
    bci_upper_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_anchor_upper_lower_bound
 *
 *   Handle the SERIF_ANCHOR action to align a serif and to set the edge
 *   anchor, then moving it again if necessary to stay within a lower and
 *   upper bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_anchor_common
 *       bci_upper_lower_bound
 */

unsigned char FPGM(bci_action_serif_anchor_upper_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_anchor_upper_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_anchor_common,
  CALL,

  PUSHB_1,
    bci_upper_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_serif_link1_common
 *
 *   Common code for bci_action_serif_link1 routines.
 *
 * CVT: cvtl_0x10000
 */

unsigned char FPGM(bci_serif_link1_common) [] =
{

  PUSHB_1,
    bci_serif_link1_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  PUSHB_1,
    3,
  CINDEX, /* s: [...] after edge before after */
  PUSHB_1,
    2,
  CINDEX, /* s: [...] after edge before after before */
  MD_orig_ZP2_0,
  PUSHB_1,
    0,
  EQ, /* after_orig_pos == before_orig_pos */
  IF, /* s: [...] after edge before */
    MDAP_noround, /* set rp0 and rp1 to `before' */
    DUP,
    ALIGNRP, /* align `edge' with `before' */
    SWAP,
    POP,

  ELSE,
    /* we have to execute `a*b/c', with b/c very near to 1: */
    /* to avoid overflow while retaining precision, */
    /* we transform this to `a + a * (b-c)/c' */

    PUSHB_1,
      2,
    CINDEX, /* s: [...] after edge before edge */
    PUSHB_1,
      2,
    CINDEX, /* s: [...] after edge before edge before */
    MD_orig_ZP2_0, /* a = edge_orig_pos - before_orig_pos */

    DUP,
    PUSHB_1,
      5,
    CINDEX, /* s: [...] after edge before a a after */
    PUSHB_1,
      4,
    CINDEX, /* s: [...] after edge before a a after before */
    MD_orig_ZP2_0, /* c = after_orig_pos - before_orig_pos */

    PUSHB_1,
      6,
    CINDEX, /* s: [...] after edge before a a c after */
    PUSHB_1,
      5,
    CINDEX, /* s: [...] after edge before a a c after before */
    MD_cur, /* b = after_pos - before_pos */

    PUSHB_1,
      2,
    CINDEX, /* s: [...] after edge before a a c b c */
    SUB, /* b-c */

    PUSHB_1,
      cvtl_0x10000,
    RCVT,
    MUL, /* (b-c) in 16.16 format */
    SWAP,

    DUP,
    IF, /* c != 0 ? */
      DIV, /* s: [...] after edge before a a (b-c)/c */
    ELSE,
      POP, /* avoid division by zero */
    EIF,

    MUL, /* a * (b-c)/c * 2^10 */
    PUSHB_1,
      cvtl_0x10000,
    RCVT,
    DIV, /* a * (b-c)/c */
    ADD, /* a*b/c */

    SWAP,
    MDAP_noround, /* set rp0 and rp1 to `before' */
    SWAP, /* s: [...] after a*b/c edge */
    DUP,
    DUP,
    ALIGNRP, /* align `edge' with `before' */
    ROLL,
    SHPIX, /* shift `edge' by `a*b/c' */

    SWAP, /* s: [...] edge after */
    POP,
  EIF,

  ENDF,

};


/*
 * bci_action_serif_link1
 *
 *   Handle the SERIF_LINK1 action to align a serif, depending on edges
 *   before and after.
 *
 * in: before_point (in twilight zone)
 *     edge_point (in twilight zone)
 *     after_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link1_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_action_serif_link1) [] =
{

  PUSHB_1,
    bci_action_serif_link1,
  FDEF,

  PUSHB_1,
    bci_serif_link1_common,
  CALL,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link1_lower_bound
 *
 *   Handle the SERIF_LINK1 action to align a serif, depending on edges
 *   before and after.  Additionally, move the serif again if necessary to
 *   stay within a lower bound.
 *
 * in: before_point (in twilight zone)
 *     edge_point (in twilight zone)
 *     after_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link1_common
 *       bci_lower_bound
 */

unsigned char FPGM(bci_action_serif_link1_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link1_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link1_common,
  CALL,

  PUSHB_1,
    bci_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link1_upper_bound
 *
 *   Handle the SERIF_LINK1 action to align a serif, depending on edges
 *   before and after.  Additionally, move the serif again if necessary to
 *   stay within an upper bound.
 *
 * in: before_point (in twilight zone)
 *     edge_point (in twilight zone)
 *     after_point (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link1_common
 *       bci_upper_bound
 */

unsigned char FPGM(bci_action_serif_link1_upper_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link1_upper_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link1_common,
  CALL,

  PUSHB_1,
    bci_upper_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link1_upper_lower_bound
 *
 *   Handle the SERIF_LINK1 action to align a serif, depending on edges
 *   before and after.  Additionally, move the serif again if necessary to
 *   stay within a lower and upper bound.
 *
 * in: before_point (in twilight zone)
 *     edge_point (in twilight zone)
 *     after_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link1_common
 *       bci_upper_lower_bound
 */

unsigned char FPGM(bci_action_serif_link1_upper_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link1_upper_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link1_common,
  CALL,

  PUSHB_1,
    bci_upper_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_serif_link2_common
 *
 *   Common code for bci_action_serif_link2 routines.
 *
 * sal: sal_anchor
 */

unsigned char FPGM(bci_serif_link2_common) [] =
{

  PUSHB_1,
    bci_serif_link2_common,
  FDEF,

  PUSHB_1,
    0,
  SZPS, /* set zp0, zp1, and zp2 to twilight zone 0 */

  DUP, /* s: [...] edge edge */
  PUSHB_1,
    sal_anchor,
  RS,
  DUP, /* s: [...] edge edge anchor anchor */
  MDAP_noround, /* set rp0 and rp1 to `sal_anchor' */

  MD_orig_ZP2_0,
  DUP,
  ADD,
  PUSHB_1,
    32,
  ADD,
  FLOOR,
  PUSHB_1,
    2*64,
  DIV, /* delta = (edge_orig_pos - anchor_orig_pos + 16) & ~31 */

  SWAP,
  DUP,
  DUP,
  ALIGNRP, /* align `edge' with `sal_anchor' */
  ROLL,
  SHPIX, /* shift `edge' by `delta' */

  ENDF,

};


/*
 * bci_action_serif_link2
 *
 *   Handle the SERIF_LINK2 action to align a serif relative to the anchor.
 *
 * in: edge_point (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link2_common
 *       bci_align_segments
 */

unsigned char FPGM(bci_action_serif_link2) [] =
{

  PUSHB_1,
    bci_action_serif_link2,
  FDEF,

  PUSHB_1,
    bci_serif_link2_common,
  CALL,

  MDAP_noround, /* set rp0 and rp1 to `edge' */

  PUSHB_2,
    bci_align_segments,
    1,
  SZP1, /* set zp1 to normal zone 1 */
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link2_lower_bound
 *
 *   Handle the SERIF_LINK2 action to align a serif relative to the anchor.
 *   Additionally, move the serif again if necessary to stay within a lower
 *   bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link2_common
 *       bci_lower_bound
 */

unsigned char FPGM(bci_action_serif_link2_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link2_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link2_common,
  CALL,

  PUSHB_1,
    bci_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link2_upper_bound
 *
 *   Handle the SERIF_LINK2 action to align a serif relative to the anchor.
 *   Additionally, move the serif again if necessary to stay within an upper
 *   bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link2_common
 *       bci_upper_bound
 */

unsigned char FPGM(bci_action_serif_link2_upper_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link2_upper_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link2_common,
  CALL,

  PUSHB_1,
    bci_upper_bound,
  CALL,

  ENDF,

};


/*
 * bci_action_serif_link2_upper_lower_bound
 *
 *   Handle the SERIF_LINK2 action to align a serif relative to the anchor.
 *   Additionally, move the serif again if necessary to stay within a lower
 *   and upper bound.
 *
 * in: edge_point (in twilight zone)
 *     edge[-1] (in twilight zone)
 *     edge[1] (in twilight zone)
 *     ... stuff for bci_align_segments (edge) ...
 *
 * uses: bci_serif_link2_common
 *       bci_upper_lower_bound
 */

unsigned char FPGM(bci_action_serif_link2_upper_lower_bound) [] =
{

  PUSHB_1,
    bci_action_serif_link2_upper_lower_bound,
  FDEF,

  PUSHB_1,
    bci_serif_link2_common,
  CALL,

  PUSHB_1,
    bci_upper_lower_bound,
  CALL,

  ENDF,

};


/*
 * bci_hint_glyph
 *
 *   This is the top-level glyph hinting function which parses the arguments
 *   on the stack and calls subroutines.
 *
 * in: action_0_func_idx
 *       ... data ...
 *     action_1_func_idx
 *       ... data ...
 *     ...
 *
 * CVT: cvtl_is_subglyph
 *
 * uses: bci_action_ip_before
 *       bci_action_ip_after
 *       bci_action_ip_on
 *       bci_action_ip_between
 *
 *       bci_action_adjust_bound
 *       bci_action_adjust_bound_serif
 *       bci_action_adjust_bound_round
 *       bci_action_adjust_bound_round_serif
 *
 *       bci_action_stem_bound
 *       bci_action_stem_bound_serif
 *       bci_action_stem_bound_round
 *       bci_action_stem_bound_round_serif
 *
 *       bci_action_link
 *       bci_action_link_serif
 *       bci_action_link_round
 *       bci_action_link_round_serif
 *
 *       bci_action_anchor
 *       bci_action_anchor_serif
 *       bci_action_anchor_round
 *       bci_action_anchor_round_serif
 *
 *       bci_action_blue_anchor
 *
 *       bci_action_adjust
 *       bci_action_adjust_serif
 *       bci_action_adjust_round
 *       bci_action_adjust_round_serif
 *
 *       bci_action_stem
 *       bci_action_stem_serif
 *       bci_action_stem_round
 *       bci_action_stem_round_serif
 *
 *       bci_action_blue
 *
 *       bci_action_serif
 *       bci_action_serif_lower_bound
 *       bci_action_serif_upper_bound
 *       bci_action_serif_upper_lower_bound
 *
 *       bci_action_serif_anchor
 *       bci_action_serif_anchor_lower_bound
 *       bci_action_serif_anchor_upper_bound
 *       bci_action_serif_anchor_upper_lower_bound
 *
 *       bci_action_serif_link1
 *       bci_action_serif_link1_lower_bound
 *       bci_action_serif_link1_upper_bound
 *       bci_action_serif_link1_upper_lower_bound
 *
 *       bci_action_serif_link2
 *       bci_action_serif_link2_lower_bound
 *       bci_action_serif_link2_upper_bound
 *       bci_action_serif_link2_upper_lower_bound
 */

unsigned char FPGM(bci_hint_glyph) [] =
{

  PUSHB_1,
    bci_hint_glyph,
  FDEF,

/* start_loop: */
  /* loop until all data on stack is used */
  CALL,
  PUSHB_1,
    8,
  NEG,
  PUSHB_1,
    3,
  DEPTH,
  LT,
  JROT, /* goto start_loop */

  PUSHB_1,
    1,
  SZP2, /* set zp2 to normal zone 1 */
  IUP_y,

  ENDF,

};


#define COPY_FPGM(func_name) \
          memcpy(buf_p, fpgm_ ## func_name, \
                 sizeof (fpgm_ ## func_name)); \
          buf_p += sizeof (fpgm_ ## func_name) \

static FT_Error
TA_table_build_fpgm(FT_Byte** fpgm,
                    FT_ULong* fpgm_len,
                    FONT* font)
{
  FT_UInt buf_len;
  FT_UInt len;
  FT_Byte* buf;
  FT_Byte* buf_p;


  /* for compatibility with dumb bytecode interpreters or analyzers, */
  /* FDEFs are stored in ascending index order, without holes -- */
  /* note that some FDEFs are not always needed */
  /* (depending on options of `TTFautohint'), */
  /* but implementing dynamic FDEF indices would be a lot of work */

  buf_len = sizeof (FPGM(bci_round))
            + sizeof (FPGM(bci_smooth_stem_width_a))
            + 1
            + sizeof (FPGM(bci_smooth_stem_width_b))
            + 1
            + sizeof (FPGM(bci_smooth_stem_width_c))
            + sizeof (FPGM(bci_get_best_width))
            + sizeof (FPGM(bci_strong_stem_width_a))
            + 2
            + sizeof (FPGM(bci_strong_stem_width_b))
            + sizeof (FPGM(bci_loop_do))
            + sizeof (FPGM(bci_loop))
            + sizeof (FPGM(bci_cvt_rescale))
            + sizeof (FPGM(bci_blue_round_a))
            + 1
            + sizeof (FPGM(bci_blue_round_b))
            + sizeof (FPGM(bci_decrement_component_counter))
            + sizeof (FPGM(bci_get_point_extrema))
            + sizeof (FPGM(bci_nibbles))
            + sizeof (FPGM(bci_number_set_is_element))
            + sizeof (FPGM(bci_number_set_is_element2))

            + sizeof (FPGM(bci_create_segment))
            + sizeof (FPGM(bci_create_segments))

            + sizeof (FPGM(bci_create_segments_0))
            + sizeof (FPGM(bci_create_segments_1))
            + sizeof (FPGM(bci_create_segments_2))
            + sizeof (FPGM(bci_create_segments_3))
            + sizeof (FPGM(bci_create_segments_4))
            + sizeof (FPGM(bci_create_segments_5))
            + sizeof (FPGM(bci_create_segments_6))
            + sizeof (FPGM(bci_create_segments_7))
            + sizeof (FPGM(bci_create_segments_8))
            + sizeof (FPGM(bci_create_segments_9))

            + sizeof (FPGM(bci_create_segments_composite))

            + sizeof (FPGM(bci_create_segments_composite_0))
            + sizeof (FPGM(bci_create_segments_composite_1))
            + sizeof (FPGM(bci_create_segments_composite_2))
            + sizeof (FPGM(bci_create_segments_composite_3))
            + sizeof (FPGM(bci_create_segments_composite_4))
            + sizeof (FPGM(bci_create_segments_composite_5))
            + sizeof (FPGM(bci_create_segments_composite_6))
            + sizeof (FPGM(bci_create_segments_composite_7))
            + sizeof (FPGM(bci_create_segments_composite_8))
            + sizeof (FPGM(bci_create_segments_composite_9))

            + sizeof (FPGM(bci_align_point))
            + sizeof (FPGM(bci_align_segment))
            + sizeof (FPGM(bci_align_segments))

            + sizeof (FPGM(bci_scale_contour))
            + sizeof (FPGM(bci_scale_glyph))
            + sizeof (FPGM(bci_scale_composite_glyph))
            + sizeof (FPGM(bci_shift_contour))
            + sizeof (FPGM(bci_shift_subglyph))

            + sizeof (FPGM(bci_ip_outer_align_point))
            + sizeof (FPGM(bci_ip_on_align_points))
            + sizeof (FPGM(bci_ip_between_align_point))
            + sizeof (FPGM(bci_ip_between_align_points))

            + sizeof (FPGM(bci_adjust_common))
            + sizeof (FPGM(bci_stem_common))
            + sizeof (FPGM(bci_serif_common))
            + sizeof (FPGM(bci_serif_anchor_common))
            + sizeof (FPGM(bci_serif_link1_common))
            + sizeof (FPGM(bci_serif_link2_common))

            + sizeof (FPGM(bci_lower_bound))
            + sizeof (FPGM(bci_upper_bound))
            + sizeof (FPGM(bci_upper_lower_bound))

            + sizeof (FPGM(bci_adjust_bound))
            + sizeof (FPGM(bci_stem_bound))
            + sizeof (FPGM(bci_link))
            + sizeof (FPGM(bci_anchor))
            + sizeof (FPGM(bci_adjust))
            + sizeof (FPGM(bci_stem))

            + sizeof (FPGM(bci_action_ip_before))
            + sizeof (FPGM(bci_action_ip_after))
            + sizeof (FPGM(bci_action_ip_on))
            + sizeof (FPGM(bci_action_ip_between))

            + sizeof (FPGM(bci_action_blue))
            + sizeof (FPGM(bci_action_blue_anchor))

            + sizeof (FPGM(bci_action_anchor))
            + sizeof (FPGM(bci_action_anchor_serif))
            + sizeof (FPGM(bci_action_anchor_round))
            + sizeof (FPGM(bci_action_anchor_round_serif))

            + sizeof (FPGM(bci_action_adjust))
            + sizeof (FPGM(bci_action_adjust_serif))
            + sizeof (FPGM(bci_action_adjust_round))
            + sizeof (FPGM(bci_action_adjust_round_serif))
            + sizeof (FPGM(bci_action_adjust_bound))
            + sizeof (FPGM(bci_action_adjust_bound_serif))
            + sizeof (FPGM(bci_action_adjust_bound_round))
            + sizeof (FPGM(bci_action_adjust_bound_round_serif))

            + sizeof (FPGM(bci_action_link))
            + sizeof (FPGM(bci_action_link_serif))
            + sizeof (FPGM(bci_action_link_round))
            + sizeof (FPGM(bci_action_link_round_serif))

            + sizeof (FPGM(bci_action_stem))
            + sizeof (FPGM(bci_action_stem_serif))
            + sizeof (FPGM(bci_action_stem_round))
            + sizeof (FPGM(bci_action_stem_round_serif))
            + sizeof (FPGM(bci_action_stem_bound))
            + sizeof (FPGM(bci_action_stem_bound_serif))
            + sizeof (FPGM(bci_action_stem_bound_round))
            + sizeof (FPGM(bci_action_stem_bound_round_serif))

            + sizeof (FPGM(bci_action_serif))
            + sizeof (FPGM(bci_action_serif_lower_bound))
            + sizeof (FPGM(bci_action_serif_upper_bound))
            + sizeof (FPGM(bci_action_serif_upper_lower_bound))

            + sizeof (FPGM(bci_action_serif_anchor))
            + sizeof (FPGM(bci_action_serif_anchor_lower_bound))
            + sizeof (FPGM(bci_action_serif_anchor_upper_bound))
            + sizeof (FPGM(bci_action_serif_anchor_upper_lower_bound))

            + sizeof (FPGM(bci_action_serif_link1))
            + sizeof (FPGM(bci_action_serif_link1_lower_bound))
            + sizeof (FPGM(bci_action_serif_link1_upper_bound))
            + sizeof (FPGM(bci_action_serif_link1_upper_lower_bound))

            + sizeof (FPGM(bci_action_serif_link2))
            + sizeof (FPGM(bci_action_serif_link2_lower_bound))
            + sizeof (FPGM(bci_action_serif_link2_upper_bound))
            + sizeof (FPGM(bci_action_serif_link2_upper_lower_bound))

            + sizeof (FPGM(bci_hint_glyph));

  /* buffer length must be a multiple of four */
  len = (buf_len + 3) & ~3;
  buf = (FT_Byte*)malloc(len);
  if (!buf)
    return FT_Err_Out_Of_Memory;

  /* pad end of buffer with zeros */
  buf[len - 1] = 0x00;
  buf[len - 2] = 0x00;
  buf[len - 3] = 0x00;

  /* copy font program into buffer and fill in the missing variables */
  buf_p = buf;

  COPY_FPGM(bci_round);
  COPY_FPGM(bci_smooth_stem_width_a);
  *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_OFFSET(font);
  COPY_FPGM(bci_smooth_stem_width_b);
  *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_OFFSET(font);
  COPY_FPGM(bci_smooth_stem_width_c);
  COPY_FPGM(bci_get_best_width);
  COPY_FPGM(bci_strong_stem_width_a);
  *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_OFFSET(font);
  *(buf_p++) = (unsigned char)CVT_VERT_WIDTHS_SIZE(font);
  COPY_FPGM(bci_strong_stem_width_b);
  COPY_FPGM(bci_loop_do);
  COPY_FPGM(bci_loop);
  COPY_FPGM(bci_cvt_rescale);
  COPY_FPGM(bci_blue_round_a);
  *(buf_p++) = (unsigned char)CVT_BLUES_SIZE(font);
  COPY_FPGM(bci_blue_round_b);
  COPY_FPGM(bci_decrement_component_counter);
  COPY_FPGM(bci_get_point_extrema);
  COPY_FPGM(bci_nibbles);
  COPY_FPGM(bci_number_set_is_element);
  COPY_FPGM(bci_number_set_is_element2);

  COPY_FPGM(bci_create_segment);
  COPY_FPGM(bci_create_segments);

  COPY_FPGM(bci_create_segments_0);
  COPY_FPGM(bci_create_segments_1);
  COPY_FPGM(bci_create_segments_2);
  COPY_FPGM(bci_create_segments_3);
  COPY_FPGM(bci_create_segments_4);
  COPY_FPGM(bci_create_segments_5);
  COPY_FPGM(bci_create_segments_6);
  COPY_FPGM(bci_create_segments_7);
  COPY_FPGM(bci_create_segments_8);
  COPY_FPGM(bci_create_segments_9);

  COPY_FPGM(bci_create_segments_composite);

  COPY_FPGM(bci_create_segments_composite_0);
  COPY_FPGM(bci_create_segments_composite_1);
  COPY_FPGM(bci_create_segments_composite_2);
  COPY_FPGM(bci_create_segments_composite_3);
  COPY_FPGM(bci_create_segments_composite_4);
  COPY_FPGM(bci_create_segments_composite_5);
  COPY_FPGM(bci_create_segments_composite_6);
  COPY_FPGM(bci_create_segments_composite_7);
  COPY_FPGM(bci_create_segments_composite_8);
  COPY_FPGM(bci_create_segments_composite_9);

  COPY_FPGM(bci_align_point);
  COPY_FPGM(bci_align_segment);
  COPY_FPGM(bci_align_segments);

  COPY_FPGM(bci_scale_contour);
  COPY_FPGM(bci_scale_glyph);
  COPY_FPGM(bci_scale_composite_glyph);
  COPY_FPGM(bci_shift_contour);
  COPY_FPGM(bci_shift_subglyph);

  COPY_FPGM(bci_ip_outer_align_point);
  COPY_FPGM(bci_ip_on_align_points);
  COPY_FPGM(bci_ip_between_align_point);
  COPY_FPGM(bci_ip_between_align_points);

  COPY_FPGM(bci_adjust_common);
  COPY_FPGM(bci_stem_common);
  COPY_FPGM(bci_serif_common);
  COPY_FPGM(bci_serif_anchor_common);
  COPY_FPGM(bci_serif_link1_common);
  COPY_FPGM(bci_serif_link2_common);

  COPY_FPGM(bci_lower_bound);
  COPY_FPGM(bci_upper_bound);
  COPY_FPGM(bci_upper_lower_bound);

  COPY_FPGM(bci_adjust_bound);
  COPY_FPGM(bci_stem_bound);
  COPY_FPGM(bci_link);
  COPY_FPGM(bci_anchor);
  COPY_FPGM(bci_adjust);
  COPY_FPGM(bci_stem);

  COPY_FPGM(bci_action_ip_before);
  COPY_FPGM(bci_action_ip_after);
  COPY_FPGM(bci_action_ip_on);
  COPY_FPGM(bci_action_ip_between);

  COPY_FPGM(bci_action_blue);
  COPY_FPGM(bci_action_blue_anchor);

  COPY_FPGM(bci_action_anchor);
  COPY_FPGM(bci_action_anchor_serif);
  COPY_FPGM(bci_action_anchor_round);
  COPY_FPGM(bci_action_anchor_round_serif);

  COPY_FPGM(bci_action_adjust);
  COPY_FPGM(bci_action_adjust_serif);
  COPY_FPGM(bci_action_adjust_round);
  COPY_FPGM(bci_action_adjust_round_serif);
  COPY_FPGM(bci_action_adjust_bound);
  COPY_FPGM(bci_action_adjust_bound_serif);
  COPY_FPGM(bci_action_adjust_bound_round);
  COPY_FPGM(bci_action_adjust_bound_round_serif);

  COPY_FPGM(bci_action_link);
  COPY_FPGM(bci_action_link_serif);
  COPY_FPGM(bci_action_link_round);
  COPY_FPGM(bci_action_link_round_serif);

  COPY_FPGM(bci_action_stem);
  COPY_FPGM(bci_action_stem_serif);
  COPY_FPGM(bci_action_stem_round);
  COPY_FPGM(bci_action_stem_round_serif);
  COPY_FPGM(bci_action_stem_bound);
  COPY_FPGM(bci_action_stem_bound_serif);
  COPY_FPGM(bci_action_stem_bound_round);
  COPY_FPGM(bci_action_stem_bound_round_serif);

  COPY_FPGM(bci_action_serif);
  COPY_FPGM(bci_action_serif_lower_bound);
  COPY_FPGM(bci_action_serif_upper_bound);
  COPY_FPGM(bci_action_serif_upper_lower_bound);

  COPY_FPGM(bci_action_serif_anchor);
  COPY_FPGM(bci_action_serif_anchor_lower_bound);
  COPY_FPGM(bci_action_serif_anchor_upper_bound);
  COPY_FPGM(bci_action_serif_anchor_upper_lower_bound);

  COPY_FPGM(bci_action_serif_link1);
  COPY_FPGM(bci_action_serif_link1_lower_bound);
  COPY_FPGM(bci_action_serif_link1_upper_bound);
  COPY_FPGM(bci_action_serif_link1_upper_lower_bound);

  COPY_FPGM(bci_action_serif_link2);
  COPY_FPGM(bci_action_serif_link2_lower_bound);
  COPY_FPGM(bci_action_serif_link2_upper_bound);
  COPY_FPGM(bci_action_serif_link2_upper_lower_bound);

  COPY_FPGM(bci_hint_glyph);

  *fpgm = buf;
  *fpgm_len = buf_len;

  return FT_Err_Ok;
}


FT_Error
TA_sfnt_build_fpgm_table(SFNT* sfnt,
                         FONT* font)
{
  FT_Error error = FT_Err_Ok;

  SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
  glyf_Data* data = (glyf_Data*)glyf_table->data;

  FT_Byte* fpgm_buf;
  FT_ULong fpgm_len;


  error = TA_sfnt_add_table_info(sfnt);
  if (error)
    goto Exit;

  /* `glyf', `cvt', `fpgm', and `prep' are always used in parallel */
  if (glyf_table->processed)
  {
    sfnt->table_infos[sfnt->num_table_infos - 1] = data->fpgm_idx;
    goto Exit;
  }

  error = TA_table_build_fpgm(&fpgm_buf, &fpgm_len, font);
  if (error)
    goto Exit;

  if (fpgm_len > sfnt->max_instructions)
    sfnt->max_instructions = fpgm_len;

  /* in case of success, `fpgm_buf' gets linked */
  /* and is eventually freed in `TA_font_unload' */
  error = TA_font_add_table(font,
                            &sfnt->table_infos[sfnt->num_table_infos - 1],
                            TTAG_fpgm, fpgm_len, fpgm_buf);
  if (error)
    free(fpgm_buf);
  else
    data->fpgm_idx = sfnt->table_infos[sfnt->num_table_infos - 1];

Exit:
  return error;
}

/* end of tafpgm.c */