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 Free Software Foundation, Inc. 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 2, or (at your option) any later 11version. 12 13GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING. If not, write to the Free 20Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2102110-1301, USA. */ 22 23 24/* This file defines all the MACHINE MODES used by GCC. 25 26 A machine mode specifies a size and format of data 27 at the machine level. 28 29 Each RTL expression has a machine mode. 30 31 At the syntax tree level, each ..._TYPE and each ..._DECL node 32 has a machine mode which describes data of that type or the 33 data of the variable declared. */ 34 35/* This file is included by the genmodes program. Its text is the 36 body of a function. Do not rely on this, it will change in the 37 future. 38 39 The following statements can be used in this file -- all have 40 the form of a C macro call. In their arguments: 41 42 A CLASS argument must be one of the constants defined in 43 mode-classes.def, less the leading MODE_ prefix; some statements 44 that take CLASS arguments have restrictions on which classes are 45 acceptable. For instance, INT. 46 47 A MODE argument must be the printable name of a machine mode, 48 without quotation marks or trailing "mode". For instance, SI. 49 50 A PRECISION, BYTESIZE, or COUNT argument must be a positive integer 51 constant. 52 53 A FORMAT argument must be one of the real_mode_format structures 54 declared in real.h, or else a literal 0. Do not put a leading & 55 on the argument. 56 57 An EXPR argument must be a syntactically valid C expression. 58 If an EXPR contains commas, you may need to write an extra pair of 59 parentheses around it, so it appears to be a single argument to the 60 statement. 61 62 This file defines only those modes which are of use on almost all 63 machines. Other modes can be defined in the target-specific 64 mode definition file, config/ARCH/ARCH-modes.def. 65 66 Order matters in this file in so far as statements which refer to 67 other modes must appear after the modes they refer to. However, 68 statements which do not refer to other modes may appear in any 69 order. 70 71 RANDOM_MODE (MODE); 72 declares MODE to be of class RANDOM. 73 74 CC_MODE (MODE); 75 declares MODE to be of class CC. 76 77 INT_MODE (MODE, BYTESIZE); 78 declares MODE to be of class INT and BYTESIZE bytes wide. 79 All of the bits of its representation are significant. 80 81 FRACTIONAL_INT_MODE (MODE, PRECISION, BYTESIZE); 82 declares MODE to be of class INT, BYTESIZE bytes wide in 83 storage, but with only PRECISION significant bits. 84 85 FLOAT_MODE (MODE, BYTESIZE, FORMAT); 86 declares MODE to be of class FLOAT and BYTESIZE bytes wide, 87 using floating point format FORMAT. 88 All of the bits of its representation are significant. 89 90 FRACTIONAL_FLOAT_MODE (MODE, PRECISION, BYTESIZE, FORMAT); 91 declares MODE to be of class FLOAT, BYTESIZE bytes wide in 92 storage, but with only PRECISION significant bits, using 93 floating point format FORMAT. 94 95 RESET_FLOAT_FORMAT (MODE, FORMAT); 96 changes the format of MODE, which must be class FLOAT, 97 to FORMAT. Use in an ARCH-modes.def to reset the format 98 of one of the float modes defined in this file. 99 100 PARTIAL_INT_MODE (MODE); 101 declares a mode of class PARTIAL_INT with the same size as 102 MODE (which must be an INT mode). The name of the new mode 103 is made by prefixing a P to the name MODE. This statement 104 may grow a PRECISION argument in the future. 105 106 VECTOR_MODE (CLASS, MODE, COUNT); 107 Declare a vector mode whose component mode is MODE (of class 108 CLASS) with COUNT components. CLASS must be INT or FLOAT. 109 The name of the vector mode takes the form VnX where n is 110 COUNT in decimal and X is MODE. 111 112 VECTOR_MODES (CLASS, WIDTH); 113 For all modes presently declared in class CLASS, construct 114 corresponding vector modes having width WIDTH. Modes whose 115 byte sizes do not evenly divide WIDTH are ignored, as are 116 modes that would produce vector modes with only one component, 117 and modes smaller than one byte (if CLASS is INT) or smaller 118 than two bytes (if CLASS is FLOAT). CLASS must be INT or 119 FLOAT. The names follow the same rule as VECTOR_MODE uses. 120 121 COMPLEX_MODES (CLASS); 122 For all modes presently declared in class CLASS, construct 123 corresponding complex modes. Modes smaller than one byte 124 are ignored. For FLOAT modes, the names are derived by 125 replacing the 'F' in the mode name with a 'C'. (It is an 126 error if there is no 'F'. For INT modes, the names are 127 derived by prefixing a C to the name. 128 129 ADJUST_BYTESIZE (MODE, EXPR); 130 ADJUST_ALIGNMENT (MODE, EXPR); 131 ADJUST_FLOAT_FORMAT (MODE, EXPR); 132 Arrange for the byte size, alignment, or floating point format 133 of MODE to be adjustable at run time. EXPR will be executed 134 once after processing all command line options, and should 135 evaluate to the desired byte size, alignment, or format. 136 137 Unlike a FORMAT argument, if you are adjusting a float format 138 you must put an & in front of the name of each format structure. 139 140 Note: If a mode is ever made which is more than 255 bytes wide, 141 machmode.h and genmodes.c will have to be changed to allocate 142 more space for the mode_size and mode_alignment arrays. */ 143 144/* VOIDmode is used when no mode needs to be specified, 145 as for example on CONST_INT RTL expressions. */ 146RANDOM_MODE (VOID); 147 148/* BLKmode is used for structures, arrays, etc. 149 that fit no more specific mode. */ 150RANDOM_MODE (BLK); 151 152/* Single bit mode used for booleans. */ 153FRACTIONAL_INT_MODE (BI, 1, 1); 154 155/* Basic integer modes. We go up to TI in generic code (128 bits). 156 The name OI is reserved for a 256-bit type (needed by some back ends). 157 FIXME TI shouldn't be generically available either. */ 158INT_MODE (QI, 1); 159INT_MODE (HI, 2); 160INT_MODE (SI, 4); 161INT_MODE (DI, 8); 162INT_MODE (TI, 16); 163 164/* No partial integer modes are defined by default. */ 165 166/* Basic floating point modes. SF and DF are the only modes provided 167 by default. The names QF, HF, XF, and TF are reserved for targets 168 that need 1-word, 2-word, 80-bit, or 128-bit float types respectively. 169 170 These are the IEEE mappings. They can be overridden with 171 RESET_FLOAT_FORMAT or at runtime (in OVERRIDE_OPTIONS). */ 172 173FLOAT_MODE (SF, 4, ieee_single_format); 174FLOAT_MODE (DF, 8, ieee_double_format); 175 176/* Basic CC modes. 177 FIXME define this only for targets that need it. */ 178CC_MODE (CC); 179 180/* Allow the target to specify additional modes of various kinds. */ 181#if HAVE_EXTRA_MODES 182# include EXTRA_MODES_FILE 183#endif 184 185/* Complex modes. */ 186COMPLEX_MODES (INT); 187COMPLEX_MODES (FLOAT); 188 189/* The symbol Pmode stands for one of the above machine modes (usually SImode). 190 The tm.h file specifies which one. It is not a distinct mode. */ 191 192/* 193Local variables: 194mode:c 195version-control: t 196End: 197*/ 198