gcc-4_8-branch/gcc/machmode.def

   1 /* This file contains the definitions and documentation for the
   2    machine modes used in the GNU compiler.
   3    Copyright (C) 1987-2013 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21
  22 /* This file defines all the MACHINE MODES used by GCC.
  23
  24    A machine mode specifies a size and format of data
  25    at the machine level.
  26
  27    Each RTL expression has a machine mode.
  28
  29    At the syntax tree level, each ..._TYPE and each ..._DECL node
  30    has a machine mode which describes data of that type or the
  31    data of the variable declared.  */
  32
  33 /* This file is included by the genmodes program.  Its text is the
  34    body of a function.  Do not rely on this, it will change in the
  35    future.
  36
  37    The following statements can be used in this file -- all have
  38    the form of a C macro call.  In their arguments:
  39
  40    A CLASS argument must be one of the constants defined in
  41    mode-classes.def, less the leading MODE_ prefix; some statements
  42    that take CLASS arguments have restrictions on which classes are
  43    acceptable.  For instance, INT.
  44
  45    A MODE argument must be the printable name of a machine mode,
  46    without quotation marks or trailing "mode".  For instance, SI.
  47
  48    A PRECISION, BYTESIZE, or COUNT argument must be a positive integer
  49    constant.
  50
  51    A FORMAT argument must be one of the real_mode_format structures
  52    declared in real.h, or else a literal 0.  Do not put a leading &
  53    on the argument.
  54
  55    An EXPR argument must be a syntactically valid C expression.
  56    If an EXPR contains commas, you may need to write an extra pair of
  57    parentheses around it, so it appears to be a single argument to the
  58    statement.
  59
  60    This file defines only those modes which are of use on almost all
  61    machines.  Other modes can be defined in the target-specific
  62    mode definition file, config/ARCH/ARCH-modes.def.
  63
  64    Order matters in this file in so far as statements which refer to
  65    other modes must appear after the modes they refer to.  However,
  66    statements which do not refer to other modes may appear in any
  67    order.
  68
  69      RANDOM_MODE (MODE);
  70         declares MODE to be of class RANDOM.
  71
  72      CC_MODE (MODE);
  73         declares MODE to be of class CC.
  74
  75      INT_MODE (MODE, BYTESIZE);
  76         declares MODE to be of class INT and BYTESIZE bytes wide.
  77         All of the bits of its representation are significant.
  78
  79      FRACTIONAL_INT_MODE (MODE, PRECISION, BYTESIZE);
  80         declares MODE to be of class INT, BYTESIZE bytes wide in
  81         storage, but with only PRECISION significant bits.
  82
  83      FLOAT_MODE (MODE, BYTESIZE, FORMAT);
  84         declares MODE to be of class FLOAT and BYTESIZE bytes wide,
  85         using floating point format FORMAT.
  86         All of the bits of its representation are significant.
  87
  88      FRACTIONAL_FLOAT_MODE (MODE, PRECISION, BYTESIZE, FORMAT);
  89         declares MODE to be of class FLOAT, BYTESIZE bytes wide in
  90         storage, but with only PRECISION significant bits, using
  91         floating point format FORMAT.
  92
  93      DECIMAL_FLOAT_MODE (MODE, BYTESIZE, FORMAT);
  94         declares MODE to be of class DECIMAL_FLOAT and BYTESIZE bytes
  95         wide.  All of the bits of its representation are significant.
  96
  97      FRACTIONAL_DECIMAL_FLOAT_MODE (MODE, BYTESIZE, FORMAT);
  98         declares MODE to be of class DECIMAL_FLOAT and BYTESIZE bytes
  99         wide.  All of the bits of its representation are significant.
 100
 101      FRACT_MODE (MODE, BYTESIZE, FBIT);
 102         declares MODE to be of class FRACT and BYTESIZE bytes wide
 103         with FBIT fractional bits.  There may be padding bits.
 104
 105      UFRACT_MODE (MODE, BYTESIZE, FBIT);
 106         declares MODE to be of class UFRACT and BYTESIZE bytes wide
 107         with FBIT fractional bits.  There may be padding bits.
 108
 109      ACCUM_MODE (MODE, BYTESIZE, IBIT, FBIT);
 110         declares MODE to be of class ACCUM and BYTESIZE bytes wide
 111         with IBIT integral bits and FBIT fractional bits.
 112         There may be padding bits.
 113
 114      UACCUM_MODE (MODE, BYTESIZE, IBIT, FBIT);
 115         declares MODE to be of class UACCUM and BYTESIZE bytes wide
 116         with IBIT integral bits and FBIT fractional bits.
 117         There may be padding bits.
 118
 119      RESET_FLOAT_FORMAT (MODE, FORMAT);
 120         changes the format of MODE, which must be class FLOAT,
 121         to FORMAT.  Use in an ARCH-modes.def to reset the format
 122         of one of the float modes defined in this file.
 123
 124      PARTIAL_INT_MODE (MODE);
 125         declares a mode of class PARTIAL_INT with the same size as
 126         MODE (which must be an INT mode).  The name of the new mode
 127         is made by prefixing a P to the name MODE.  This statement
 128         may grow a PRECISION argument in the future.
 129
 130      VECTOR_MODE (CLASS, MODE, COUNT);
 131         Declare a vector mode whose component mode is MODE (of class
 132         CLASS) with COUNT components.  CLASS must be INT or FLOAT.
 133         The name of the vector mode takes the form VnX where n is
 134         COUNT in decimal and X is MODE.
 135
 136      VECTOR_MODES (CLASS, WIDTH);
 137         For all modes presently declared in class CLASS, construct
 138         corresponding vector modes having width WIDTH.  Modes whose
 139         byte sizes do not evenly divide WIDTH are ignored, as are
 140         modes that would produce vector modes with only one component,
 141         and modes smaller than one byte (if CLASS is INT) or smaller
 142         than two bytes (if CLASS is FLOAT).  CLASS must be INT or
 143         FLOAT.  The names follow the same rule as VECTOR_MODE uses.
 144
 145      COMPLEX_MODES (CLASS);
 146         For all modes presently declared in class CLASS, construct
 147         corresponding complex modes.  Modes smaller than one byte
 148         are ignored.  For FLOAT modes, the names are derived by
 149         replacing the 'F' in the mode name with a 'C'.  (It is an
 150         error if there is no 'F'.  For INT modes, the names are
 151         derived by prefixing a C to the name.
 152
 153      ADJUST_BYTESIZE (MODE, EXPR);
 154      ADJUST_ALIGNMENT (MODE, EXPR);
 155      ADJUST_FLOAT_FORMAT (MODE, EXPR);
 156      ADJUST_IBIT (MODE, EXPR);
 157      ADJUST_FBIT (MODE, EXPR);
 158         Arrange for the byte size, alignment, floating point format, ibit,
 159         or fbit of MODE to be adjustable at run time.  EXPR will be executed
 160         once after processing all command line options, and should
 161         evaluate to the desired byte size, alignment, format, ibit or fbit.
 162
 163         Unlike a FORMAT argument, if you are adjusting a float format
 164         you must put an & in front of the name of each format structure.
 165
 166    Note: If a mode is ever made which is more than 255 bytes wide,
 167    machmode.h and genmodes.c will have to be changed to allocate
 168    more space for the mode_size and mode_alignment arrays.  */
 169
 170 /* VOIDmode is used when no mode needs to be specified,
 171    as for example on CONST_INT RTL expressions.  */
 172 RANDOM_MODE (VOID);
 173
 174 /* BLKmode is used for structures, arrays, etc.
 175    that fit no more specific mode.  */
 176 RANDOM_MODE (BLK);
 177
 178 /* Single bit mode used for booleans.  */
 179 FRACTIONAL_INT_MODE (BI, 1, 1);
 180
 181 /* Basic integer modes.  We go up to TI in generic code (128 bits).
 182    The name OI is reserved for a 256-bit type (needed by some back ends).
 183    FIXME TI shouldn't be generically available either.  */
 184 INT_MODE (QI, 1);
 185 INT_MODE (HI, 2);
 186 INT_MODE (SI, 4);
 187 INT_MODE (DI, 8);
 188 INT_MODE (TI, 16);
 189
 190 /* No partial integer modes are defined by default.  */
 191
 192 /* Basic floating point modes.  SF and DF are the only modes provided
 193    by default.  The names QF, HF, XF, and TF are reserved for targets
 194    that need 1-word, 2-word, 80-bit, or 128-bit float types respectively.
 195
 196    These are the IEEE mappings.  They can be overridden with
 197    RESET_FLOAT_FORMAT or at runtime (in TARGET_OPTION_OVERRIDE).  */
 198
 199 FLOAT_MODE (SF, 4, ieee_single_format);
 200 FLOAT_MODE (DF, 8, ieee_double_format);
 201
 202 /* Basic CC modes.
 203    FIXME define this only for targets that need it.  */
 204 CC_MODE (CC);
 205
 206 /* Fixed-point modes.  */
 207 FRACT_MODE (QQ, 1, 7); /* s.7 */
 208 FRACT_MODE (HQ, 2, 15); /* s.15 */
 209 FRACT_MODE (SQ, 4, 31); /* s.31 */
 210 FRACT_MODE (DQ, 8, 63); /* s.63 */
 211 FRACT_MODE (TQ, 16, 127); /* s.127 */
 212
 213 UFRACT_MODE (UQQ, 1, 8); /* .8 */
 214 UFRACT_MODE (UHQ, 2, 16); /* .16 */
 215 UFRACT_MODE (USQ, 4, 32); /* .32 */
 216 UFRACT_MODE (UDQ, 8, 64); /* .64 */
 217 UFRACT_MODE (UTQ, 16, 128); /* .128 */
 218
 219 ACCUM_MODE (HA, 2, 8, 7); /* s8.7 */
 220 ACCUM_MODE (SA, 4, 16, 15); /* s16.15 */
 221 ACCUM_MODE (DA, 8, 32, 31); /* s32.31 */
 222 ACCUM_MODE (TA, 16, 64, 63); /* s64.63 */
 223
 224 UACCUM_MODE (UHA, 2, 8, 8); /* 8.8 */
 225 UACCUM_MODE (USA, 4, 16, 16); /* 16.16 */
 226 UACCUM_MODE (UDA, 8, 32, 32); /* 32.32 */
 227 UACCUM_MODE (UTA, 16, 64, 64); /* 64.64 */
 228
 229 /* Allow the target to specify additional modes of various kinds.  */
 230 #if HAVE_EXTRA_MODES
 231 # include EXTRA_MODES_FILE
 232 #endif
 233
 234 /* Complex modes.  */
 235 COMPLEX_MODES (INT);
 236 COMPLEX_MODES (FLOAT);
 237
 238 /* Decimal floating point modes.  */
 239 DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
 240 DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
 241 DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
 242
 243 /* The symbol Pmode stands for one of the above machine modes (usually SImode).
 244    The tm.h file specifies which one.  It is not a distinct mode.  */
 245
 246 /*
 247 Local variables:
 248 mode:c
 249 version-control: t
 250 End:
 251 */