1 /* This file contains the definitions and documentation for the
2 machine modes used in the GNU compiler.
3 Copyright (C) 1987-2022 Free Software Foundation, Inc.
5 This file is part of GCC.
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
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
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/>. */
22 /* This file defines all the MACHINE MODES used by GCC.
24 A machine mode specifies a size and format of data
27 Each RTL expression has a machine mode.
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. */
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
37 The following statements can be used in this file -- all have
38 the form of a C macro call. In their arguments:
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.
45 A MODE argument must be the printable name of a machine mode,
46 without quotation marks or trailing "mode". For instance, SI.
48 A PRECISION, BYTESIZE, or COUNT argument must be a positive integer
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 &
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
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.
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
70 declares MODE to be of class RANDOM.
73 declares MODE to be of class CC.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
124 PARTIAL_INT_MODE (MODE, PRECISION, NAME);
125 declares a mode of class PARTIAL_INT with the same size as
126 MODE (which must be an INT mode) and precision PREC.
127 Optionally, NAME is the new name of the mode. NAME is the
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.
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.
145 VECTOR_MODES_WITH_PREFIX (PREFIX, CLASS, WIDTH, ORDER);
146 Like VECTOR_MODES, but start the mode names with PREFIX instead
147 of the usual "V". ORDER is the top-level sorting order of the
148 mode, with smaller numbers indicating a higher priority.
150 VECTOR_BOOL_MODE (NAME, COUNT, COMPONENT, BYTESIZE)
151 Create a vector mode called NAME that contains COUNT boolean
152 elements and occupies BYTESIZE bytes in total. Each boolean
153 element is of COMPONENT type and occupies (COUNT * BITS_PER_UNIT) /
154 BYTESIZE bits, with the element at index 0 occupying the lsb of the
155 first byte in memory. Only the lowest bit of each element is
158 OPAQUE_MODE (NAME, BYTESIZE)
159 Create an opaque mode called NAME that is BYTESIZE bytes wide.
161 COMPLEX_MODES (CLASS);
162 For all modes presently declared in class CLASS, construct
163 corresponding complex modes. Modes smaller than one byte
164 are ignored. For FLOAT modes, the names are derived by
165 replacing the 'F' in the mode name with a 'C'. (It is an
166 error if there is no 'F'. For INT modes, the names are
167 derived by prefixing a C to the name.
169 ADJUST_BYTESIZE (MODE, EXPR);
170 ADJUST_ALIGNMENT (MODE, EXPR);
171 ADJUST_FLOAT_FORMAT (MODE, EXPR);
172 ADJUST_IBIT (MODE, EXPR);
173 ADJUST_FBIT (MODE, EXPR);
174 Arrange for the byte size, alignment, floating point format, ibit,
175 or fbit of MODE to be adjustable at run time. EXPR will be executed
176 once after processing all command line options, and should
177 evaluate to the desired byte size, alignment, format, ibit or fbit.
179 Unlike a FORMAT argument, if you are adjusting a float format
180 you must put an & in front of the name of each format structure.
182 ADJUST_NUNITS (MODE, EXPR);
183 Like the above, but set the number of nunits of MODE to EXPR.
184 This changes the size and precision of the mode in proportion
185 to the change in the number of units; for example, doubling
186 the number of units doubles the size and precision as well.
188 Note: If a mode is ever made which is more than 255 bytes wide,
189 machmode.h and genmodes.cc will have to be changed to allocate
190 more space for the mode_size and mode_alignment arrays. */
192 /* VOIDmode is used when no mode needs to be specified,
193 as for example on CONST_INT RTL expressions. */
196 /* BLKmode is used for structures, arrays, etc.
197 that fit no more specific mode. */
200 /* Single bit mode used for booleans. */
201 BOOL_MODE (BI, 1, 1);
203 /* Basic integer modes. We go up to TI in generic code (128 bits).
204 TImode is needed here because the some front ends now genericly
205 support __int128. If the front ends decide to generically support
206 larger types, then corresponding modes must be added here. The
207 name OI is reserved for a 256-bit type (needed by some back ends).
215 /* No partial integer modes are defined by default. */
217 /* The target normally defines any target-specific __intN types and
218 their modes, but __int128 for TImode is fairly common so define it
219 here. The type will not be created unless the target supports
224 /* Basic floating point modes. SF and DF are the only modes provided
225 by default. The names QF, HF, XF, and TF are reserved for targets
226 that need 1-word, 2-word, 80-bit, or 128-bit float types respectively.
228 These are the IEEE mappings. They can be overridden with
229 RESET_FLOAT_FORMAT or at runtime (in TARGET_OPTION_OVERRIDE). */
231 FLOAT_MODE (SF, 4, ieee_single_format);
232 FLOAT_MODE (DF, 8, ieee_double_format);
235 FIXME define this only for targets that need it. */
238 /* Fixed-point modes. */
239 FRACT_MODE (QQ, 1, 7); /* s.7 */
240 FRACT_MODE (HQ, 2, 15); /* s.15 */
241 FRACT_MODE (SQ, 4, 31); /* s.31 */
242 FRACT_MODE (DQ, 8, 63); /* s.63 */
243 FRACT_MODE (TQ, 16, 127); /* s.127 */
245 UFRACT_MODE (UQQ, 1, 8); /* .8 */
246 UFRACT_MODE (UHQ, 2, 16); /* .16 */
247 UFRACT_MODE (USQ, 4, 32); /* .32 */
248 UFRACT_MODE (UDQ, 8, 64); /* .64 */
249 UFRACT_MODE (UTQ, 16, 128); /* .128 */
251 ACCUM_MODE (HA, 2, 8, 7); /* s8.7 */
252 ACCUM_MODE (SA, 4, 16, 15); /* s16.15 */
253 ACCUM_MODE (DA, 8, 32, 31); /* s32.31 */
254 ACCUM_MODE (TA, 16, 64, 63); /* s64.63 */
256 UACCUM_MODE (UHA, 2, 8, 8); /* 8.8 */
257 UACCUM_MODE (USA, 4, 16, 16); /* 16.16 */
258 UACCUM_MODE (UDA, 8, 32, 32); /* 32.32 */
259 UACCUM_MODE (UTA, 16, 64, 64); /* 64.64 */
261 /* Allow the target to specify additional modes of various kinds. */
263 # include EXTRA_MODES_FILE
268 COMPLEX_MODES (PARTIAL_INT);
269 COMPLEX_MODES (FLOAT);
271 /* Decimal floating point modes. */
272 DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
273 DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
274 DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
276 /* The symbol Pmode stands for one of the above machine modes (usually SImode).
277 The tm.h file specifies which one. It is not a distinct mode. */