1/* This file contains the definitions and documentation for the
2 machine modes used in the GNU compiler.
3 Copyright (C) 1987-2017 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along 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, 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
128 name of the mode.
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. */
172RANDOM_MODE (VOID);
173
174/* BLKmode is used for structures, arrays, etc.
175 that fit no more specific mode. */
176RANDOM_MODE (BLK);
177
178/* Single bit mode used for booleans. */
179FRACTIONAL_INT_MODE (BI, 1, 1);
180
181/* Basic integer modes. We go up to TI in generic code (128 bits).
182 TImode is needed here because the some front ends now genericly
183 support __int128. If the front ends decide to generically support
184 larger types, then corresponding modes must be added here. The
185 name OI is reserved for a 256-bit type (needed by some back ends).
186 */
187INT_MODE (QI, 1);
188INT_MODE (HI, 2);
189INT_MODE (SI, 4);
190INT_MODE (DI, 8);
191INT_MODE (TI, 16);
192
193/* No partial integer modes are defined by default. */
194
195/* The target normally defines any target-specific __intN types and
196 their modes, but __int128 for TImode is fairly common so define it
197 here. The type will not be created unless the target supports
198 TImode. */
199
200INT_N (TI, 128);
201
202/* Basic floating point modes. SF and DF are the only modes provided
203 by default. The names QF, HF, XF, and TF are reserved for targets
204 that need 1-word, 2-word, 80-bit, or 128-bit float types respectively.
205
206 These are the IEEE mappings. They can be overridden with
207 RESET_FLOAT_FORMAT or at runtime (in TARGET_OPTION_OVERRIDE). */
208
209FLOAT_MODE (SF, 4, ieee_single_format);
210FLOAT_MODE (DF, 8, ieee_double_format);
211
212/* Basic CC modes.
213 FIXME define this only for targets that need it. */
214CC_MODE (CC);
215
216/* Fixed-point modes. */
217FRACT_MODE (QQ, 1, 7); /* s.7 */
218FRACT_MODE (HQ, 2, 15); /* s.15 */
219FRACT_MODE (SQ, 4, 31); /* s.31 */
220FRACT_MODE (DQ, 8, 63); /* s.63 */
221FRACT_MODE (TQ, 16, 127); /* s.127 */
222
223UFRACT_MODE (UQQ, 1, 8); /* .8 */
224UFRACT_MODE (UHQ, 2, 16); /* .16 */
225UFRACT_MODE (USQ, 4, 32); /* .32 */
226UFRACT_MODE (UDQ, 8, 64); /* .64 */
227UFRACT_MODE (UTQ, 16, 128); /* .128 */
228
229ACCUM_MODE (HA, 2, 8, 7); /* s8.7 */
230ACCUM_MODE (SA, 4, 16, 15); /* s16.15 */
231ACCUM_MODE (DA, 8, 32, 31); /* s32.31 */
232ACCUM_MODE (TA, 16, 64, 63); /* s64.63 */
233
234UACCUM_MODE (UHA, 2, 8, 8); /* 8.8 */
235UACCUM_MODE (USA, 4, 16, 16); /* 16.16 */
236UACCUM_MODE (UDA, 8, 32, 32); /* 32.32 */
237UACCUM_MODE (UTA, 16, 64, 64); /* 64.64 */
238
239/* Allow the target to specify additional modes of various kinds. */
240#if HAVE_EXTRA_MODES
241# include EXTRA_MODES_FILE
242#endif
243
244/* Complex modes. */
245COMPLEX_MODES (INT);
246COMPLEX_MODES (FLOAT);
247
248/* Decimal floating point modes. */
249DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
250DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
251DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
252
253/* The symbol Pmode stands for one of the above machine modes (usually SImode).
254 The tm.h file specifies which one. It is not a distinct mode. */
255
256/*
257Local variables:
258mode:c
259version-control: t
260End:
261*/
262