* config/mips/mips.c (function_arg): Where one part of a
[official-gcc.git] / gcc / machmode.def
blobffb675d14f0354c0f6d70d8310e7815a1b8af1d0
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.
6 This file is part of GCC.
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 2, or (at your option) any later
11 version.
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.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
21 02110-1301, USA. */
24 /* This file defines all the MACHINE MODES used by GCC.
26 A machine mode specifies a size and format of data
27 at the machine level.
29 Each RTL expression has a machine mode.
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. */
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.
39 The following statements can be used in this file -- all have
40 the form of a C macro call. In their arguments:
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.
47 A MODE argument must be the printable name of a machine mode,
48 without quotation marks or trailing "mode". For instance, SI.
50 A PRECISION, BYTESIZE, or COUNT argument must be a positive integer
51 constant.
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.
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.
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.
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.
71 RANDOM_MODE (MODE);
72 declares MODE to be of class RANDOM.
74 CC_MODE (MODE);
75 declares MODE to be of class CC.
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.
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.
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.
90 DECIMAL FLOAT_MODE (MODE, BYTESIZE);
91 declares MODE to be of class DECIMAL_FLOAT and BYTESIZE bytes
92 wide. All of the bits of its representation are significant.
94 FRACTIONAL_FLOAT_MODE (MODE, PRECISION, BYTESIZE, FORMAT);
95 declares MODE to be of class FLOAT, BYTESIZE bytes wide in
96 storage, but with only PRECISION significant bits, using
97 floating point format FORMAT.
99 RESET_FLOAT_FORMAT (MODE, FORMAT);
100 changes the format of MODE, which must be class FLOAT,
101 to FORMAT. Use in an ARCH-modes.def to reset the format
102 of one of the float modes defined in this file.
104 PARTIAL_INT_MODE (MODE);
105 declares a mode of class PARTIAL_INT with the same size as
106 MODE (which must be an INT mode). The name of the new mode
107 is made by prefixing a P to the name MODE. This statement
108 may grow a PRECISION argument in the future.
110 VECTOR_MODE (CLASS, MODE, COUNT);
111 Declare a vector mode whose component mode is MODE (of class
112 CLASS) with COUNT components. CLASS must be INT or FLOAT.
113 The name of the vector mode takes the form VnX where n is
114 COUNT in decimal and X is MODE.
116 VECTOR_MODES (CLASS, WIDTH);
117 For all modes presently declared in class CLASS, construct
118 corresponding vector modes having width WIDTH. Modes whose
119 byte sizes do not evenly divide WIDTH are ignored, as are
120 modes that would produce vector modes with only one component,
121 and modes smaller than one byte (if CLASS is INT) or smaller
122 than two bytes (if CLASS is FLOAT). CLASS must be INT or
123 FLOAT. The names follow the same rule as VECTOR_MODE uses.
125 COMPLEX_MODES (CLASS);
126 For all modes presently declared in class CLASS, construct
127 corresponding complex modes. Modes smaller than one byte
128 are ignored. For FLOAT modes, the names are derived by
129 replacing the 'F' in the mode name with a 'C'. (It is an
130 error if there is no 'F'. For INT modes, the names are
131 derived by prefixing a C to the name.
133 ADJUST_BYTESIZE (MODE, EXPR);
134 ADJUST_ALIGNMENT (MODE, EXPR);
135 ADJUST_FLOAT_FORMAT (MODE, EXPR);
136 Arrange for the byte size, alignment, or floating point format
137 of MODE to be adjustable at run time. EXPR will be executed
138 once after processing all command line options, and should
139 evaluate to the desired byte size, alignment, or format.
141 Unlike a FORMAT argument, if you are adjusting a float format
142 you must put an & in front of the name of each format structure.
144 Note: If a mode is ever made which is more than 255 bytes wide,
145 machmode.h and genmodes.c will have to be changed to allocate
146 more space for the mode_size and mode_alignment arrays. */
148 /* VOIDmode is used when no mode needs to be specified,
149 as for example on CONST_INT RTL expressions. */
150 RANDOM_MODE (VOID);
152 /* BLKmode is used for structures, arrays, etc.
153 that fit no more specific mode. */
154 RANDOM_MODE (BLK);
156 /* Single bit mode used for booleans. */
157 FRACTIONAL_INT_MODE (BI, 1, 1);
159 /* Basic integer modes. We go up to TI in generic code (128 bits).
160 The name OI is reserved for a 256-bit type (needed by some back ends).
161 FIXME TI shouldn't be generically available either. */
162 INT_MODE (QI, 1);
163 INT_MODE (HI, 2);
164 INT_MODE (SI, 4);
165 INT_MODE (DI, 8);
166 INT_MODE (TI, 16);
168 /* No partial integer modes are defined by default. */
170 /* Basic floating point modes. SF and DF are the only modes provided
171 by default. The names QF, HF, XF, and TF are reserved for targets
172 that need 1-word, 2-word, 80-bit, or 128-bit float types respectively.
174 These are the IEEE mappings. They can be overridden with
175 RESET_FLOAT_FORMAT or at runtime (in OVERRIDE_OPTIONS). */
177 FLOAT_MODE (SF, 4, ieee_single_format);
178 FLOAT_MODE (DF, 8, ieee_double_format);
180 /* Basic CC modes.
181 FIXME define this only for targets that need it. */
182 CC_MODE (CC);
184 /* Allow the target to specify additional modes of various kinds. */
185 #if HAVE_EXTRA_MODES
186 # include EXTRA_MODES_FILE
187 #endif
189 /* Complex modes. */
190 COMPLEX_MODES (INT);
191 COMPLEX_MODES (FLOAT);
193 /* Decimal floating point modes. */
194 DECIMAL_FLOAT_MODE (SD, 4, decimal_single_format);
195 DECIMAL_FLOAT_MODE (DD, 8, decimal_double_format);
196 DECIMAL_FLOAT_MODE (TD, 16, decimal_quad_format);
198 /* The symbol Pmode stands for one of the above machine modes (usually SImode).
199 The tm.h file specifies which one. It is not a distinct mode. */
202 Local variables:
203 mode:c
204 version-control: t
205 End: