gcc/machmode.def

   1 /* This file contains the definitions and documentation for the
   2    machine modes used in the GNU compiler.
   3    Copyright (C) 1987, 1992, 1994, 1997, 1998, 2000, 2003, 2004, 2005,
   4    2007  Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 /* This file defines all the MACHINE MODES used by GCC.
  24
  25    A machine mode specifies a size and format of data
  26    at the machine level.
  27
  28    Each RTL expression has a machine mode.
  29
  30    At the syntax tree level, each ..._TYPE and each ..._DECL node
  31    has a machine mode which describes data of that type or the
  32    data of the variable declared.  */
  33
  34 /* This file is included by the genmodes program.  Its text is the
  35    body of a function.  Do not rely on this, it will change in the
  36    future.
  37
  38    The following statements can be used in this file -- all have
  39    the form of a C macro call.  In their arguments:
  40
  41    A CLASS argument must be one of the constants defined in
  42    mode-classes.def, less the leading MODE_ prefix; some statements
  43    that take CLASS arguments have restrictions on which classes are
  44    acceptable.  For instance, INT.
  45
  46    A MODE argument must be the printable name of a machine mode,
  47    without quotation marks or trailing "mode".  For instance, SI.
  48
  49    A PRECISION, BYTESIZE, or COUNT argument must be a positive integer
  50    constant.
  51
  52    A FORMAT argument must be one of the real_mode_format structures
  53    declared in real.h, or else a literal 0.  Do not put a leading &
  54    on the argument.
  55
  56    An EXPR argument must be a syntactically valid C expression.
  57    If an EXPR contains commas, you may need to write an extra pair of
  58    parentheses around it, so it appears to be a single argument to the
  59    statement.
  60
  61    This file defines only those modes which are of use on almost all
  62    machines.  Other modes can be defined in the target-specific
  63    mode definition file, config/ARCH/ARCH-modes.def.
  64
  65    Order matters in this file in so far as statements which refer to
  66    other modes must appear after the modes they refer to.  However,
  67    statements which do not refer to other modes may appear in any
  68    order.
  69
  70      RANDOM_MODE (MODE);
  71         declares MODE to be of class RANDOM.
  72
  73      CC_MODE (MODE);
  74         declares MODE to be of class CC.
  75
  76      INT_MODE (MODE, BYTESIZE);
  77         declares MODE to be of class INT and BYTESIZE bytes wide.
  78         All of the bits of its representation are significant.
  79
  80      FRACTIONAL_INT_MODE (MODE, PRECISION, BYTESIZE);
  81         declares MODE to be of class INT, BYTESIZE bytes wide in
  82         storage, but with only PRECISION significant bits.
  83
  84      FLOAT_MODE (MODE, BYTESIZE, FORMAT);
  85         declares MODE to be of class FLOAT and BYTESIZE bytes wide,
  86         using floating point format FORMAT.
  87         All of the bits of its representation are significant.
  88
  89      DECIMAL FLOAT_MODE (MODE, BYTESIZE);
  90         declares MODE to be of class DECIMAL_FLOAT and BYTESIZE bytes
  91         wide.  All of the bits of its representation are significant.
  92
  93      FRACTIONAL_FLOAT_MODE (MODE, PRECISION, BYTESIZE, FORMAT);
  94         declares MODE to be of class FLOAT, BYTESIZE bytes wide in
  95         storage, but with only PRECISION significant bits, using
  96         floating point format FORMAT.
  97
  98      FRACT_MODE (MODE, BYTESIZE, FBIT);
  99         declares MODE to be of class FRACT and BYTESIZE bytes wide
 100         with FBIT fractional bits.  There may be padding bits.
 101
 102      UFRACT_MODE (MODE, BYTESIZE, FBIT);
 103         declares MODE to be of class UFRACT and BYTESIZE bytes wide
 104         with FBIT fractional bits.  There may be padding bits.
 105
 106      ACCUM_MODE (MODE, BYTESIZE, IBIT, FBIT);
 107         declares MODE to be of class ACCUM and BYTESIZE bytes wide
 108         with IBIT integral bits and FBIT fractional bits.
 109         There may be padding bits.
 110
 111      UACCUM_MODE (MODE, BYTESIZE, FBIT);
 112         declares MODE to be of class UACCUM and BYTESIZE bytes wide
 113         with IBIT integral bits and FBIT fractional bits.
 114         There may be padding bits.
 115
 116      RESET_FLOAT_FORMAT (MODE, FORMAT);
 117         changes the format of MODE, which must be class FLOAT,
 118         to FORMAT.  Use in an ARCH-modes.def to reset the format
 119         of one of the float modes defined in this file.
 120
 121      PARTIAL_INT_MODE (MODE);
 122         declares a mode of class PARTIAL_INT with the same size as
 123         MODE (which must be an INT mode).  The name of the new mode
 124         is made by prefixing a P to the name MODE.  This statement
 125         may grow a PRECISION argument in the future.
 126
 127      VECTOR_MODE (CLASS, MODE, COUNT);
 128         Declare a vector mode whose component mode is MODE (of class
 129         CLASS) with COUNT components.  CLASS must be INT or FLOAT.
 130         The name of the vector mode takes the form VnX where n is
 131         COUNT in decimal and X is MODE.
 132
 133      VECTOR_MODES (CLASS, WIDTH);
 134         For all modes presently declared in class CLASS, construct
 135         corresponding vector modes having width WIDTH.  Modes whose
 136         byte sizes do not evenly divide WIDTH are ignored, as are
 137         modes that would produce vector modes with only one component,
 138         and modes smaller than one byte (if CLASS is INT) or smaller
 139         than two bytes (if CLASS is FLOAT).  CLASS must be INT or
 140         FLOAT.  The names follow the same rule as VECTOR_MODE uses.
 141
 142      COMPLEX_MODES (CLASS);
 143         For all modes presently declared in class CLASS, construct
 144         corresponding complex modes.  Modes smaller than one byte
 145         are ignored.  For FLOAT modes, the names are derived by
 146         replacing the 'F' in the mode name with a 'C'.  (It is an
 147         error if there is no 'F'.  For INT modes, the names are
 148         derived by prefixing a C to the name.
 149
 150      ADJUST_BYTESIZE (MODE, EXPR);
 151      ADJUST_ALIGNMENT (MODE, EXPR);
 152      ADJUST_FLOAT_FORMAT (MODE, EXPR);
 153      ADJUST_IBIT (MODE, EXPR);
 154      ADJUST_FBIT (MODE, EXPR);
 155         Arrange for the byte size, alignment, floating point format, ibit,
 156         or fbit of MODE to be adjustable at run time.  EXPR will be executed
 157         once after processing all command line options, and should
 158         evaluate to the desired byte size, alignment, format, ibit or fbit.
 159
 160         Unlike a FORMAT argument, if you are adjusting a float format
 161         you must put an & in front of the name of each format structure.
 162
 163    Note: If a mode is ever made which is more than 255 bytes wide,
 164    machmode.h and genmodes.c will have to be changed to allocate
 165    more space for the mode_size and mode_alignment arrays.  */
 166
 167 /* VOIDmode is used when no mode needs to be specified,
 168    as for example on CONST_INT RTL expressions.  */
 169 RANDOM_MODE (VOID);
 170
 171 /* BLKmode is used for structures, arrays, etc.
 172    that fit no more specific mode.  */
 173 RANDOM_MODE (BLK);
 174
 175 /* Single bit mode used for booleans.  */
 176 FRACTIONAL_INT_MODE (BI, 1, 1);
 177
 178 /* Basic integer modes.  We go up to TI in generic code (128 bits).
 179    The name OI is reserved for a 256-bit type (needed by some back ends).
 180    FIXME TI shouldn't be generically available either.  */
 181 INT_MODE (QI, 1);
 182 INT_MODE (HI, 2);
 183 INT_MODE (SI, 4);
 184 INT_MODE (DI, 8);
 185 INT_MODE (TI, 16);
 186
 187 /* No partial integer modes are defined by default.  */
 188
 189 /* Basic floating point modes.  SF and DF are the only modes provided
 190    by default.  The names QF, HF, XF, and TF are reserved for targets
 191    that need 1-word, 2-word, 80-bit, or 128-bit float types respectively.
 192
 193    These are the IEEE mappings.  They can be overridden with
 194    RESET_FLOAT_FORMAT or at runtime (in OVERRIDE_OPTIONS).  */
 195
 196 FLOAT_MODE (SF, 4, ieee_single_format);
 197 FLOAT_MODE (DF, 8, ieee_double_format);
 198
 199 /* Basic CC modes.
 200    FIXME define this only for targets that need it.  */
 201 CC_MODE (CC);
 202
 203 /* Fixed-point modes.  */
 204 FRACT_MODE (QQ, 1, 7); /* s.7 */
 205 FRACT_MODE (HQ, 2, 15); /* s.15 */
 206 FRACT_MODE (SQ, 4, 31); /* s.31 */
 207 FRACT_MODE (DQ, 8, 63); /* s.63 */
 208 FRACT_MODE (TQ, 16, 127); /* s.127 */
 209
 210 UFRACT_MODE (UQQ, 1, 8); /* .8 */
 211 UFRACT_MODE (UHQ, 2, 16); /* .16 */
 212 UFRACT_MODE (USQ, 4, 32); /* .32 */
 213 UFRACT_MODE (UDQ, 8, 64); /* .64 */
 214 UFRACT_MODE (UTQ, 16, 128); /* .128 */
 215
 216 ACCUM_MODE (HA, 2, 8, 7); /* s8.7 */
 217 ACCUM_MODE (SA, 4, 16, 15); /* s16.15 */
 218 ACCUM_MODE (DA, 8, 32, 31); /* s32.31 */
 219 ACCUM_MODE (TA, 16, 64, 63); /* s64.63 */
 220
 221 UACCUM_MODE (UHA, 2, 8, 8); /* 8.8 */
 222 UACCUM_MODE (USA, 4, 16, 16); /* 16.16 */
 223 UACCUM_MODE (UDA, 8, 32, 32); /* 32.32 */
 224 UACCUM_MODE (UTA, 16, 64, 64); /* 64.64 */
 225
 226 /* Allow the target to specify additional modes of various kinds.  */
 227 #if HAVE_EXTRA_MODES
 228 # include EXTRA_MODES_FILE
 229 #endif
 230
 231 /* Complex modes.  */
 232 COMPLEX_MODES (INT);
 233 COMPLEX_MODES (FLOAT);
 234
 235 /* Decimal floating point modes.  */
 236 DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
 237 DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
 238 DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
 239
 240 /* The symbol Pmode stands for one of the above machine modes (usually SImode).
 241    The tm.h file specifies which one.  It is not a distinct mode.  */
 242
 243 /*
 244 Local variables:
 245 mode:c
 246 version-control: t
 247 End:
 248 */