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1.1 root 1: /* Target definitions for GNU compiler for Intel 80386 running System V.4
2: Copyright (C) 1991 Free Software Foundation, Inc.
3:
4: Written by Ron Guilmette ([email protected]).
5:
6: This file is part of GNU CC.
7:
8: GNU CC is free software; you can redistribute it and/or modify
9: it under the terms of the GNU General Public License as published by
10: the Free Software Foundation; either version 2, or (at your option)
11: any later version.
12:
13: GNU CC is distributed in the hope that it will be useful,
14: but WITHOUT ANY WARRANTY; without even the implied warranty of
15: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16: GNU General Public License for more details.
17:
18: You should have received a copy of the GNU General Public License
19: along with GNU CC; see the file COPYING. If not, write to
20: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21:
22: #include "i386.h" /* Base i386 target machine definitions */
23: #include "att386.h" /* Use the i386 AT&T assembler syntax */
24: #include "svr4.h" /* Definitions common to all SVR4 targets */
1.1.1.2 ! root 25: #include "real.h"
1.1 root 26:
27: #undef TARGET_VERSION
28: #define TARGET_VERSION fprintf (stderr, " (i386 System V Release 4)");
29:
30: /* By default, target has a 80387. */
31:
32: #define TARGET_DEFAULT 1
33:
34: /* Machines that use the AT&T assembler syntax
35: also return floating point values in an FP register. */
36: /* Define how to find the value returned by a function.
37: VALTYPE is the data type of the value (as a tree).
38: If the precise function being called is known, FUNC is its FUNCTION_DECL;
39: otherwise, FUNC is 0. */
40:
41: #define VALUE_REGNO(MODE) \
42: (((MODE) == SFmode || (MODE) == DFmode) ? FIRST_FLOAT_REG : 0)
43:
44: /* 1 if N is a possible register number for a function value. */
45:
46: #define FUNCTION_VALUE_REGNO_P(N) ((N) == 0 || (N)== FIRST_FLOAT_REG)
47:
48: /* The svr4 ABI for the i386 says that records and unions are returned
49: in memory. */
50:
51: #undef RETURN_IN_MEMORY
52: #define RETURN_IN_MEMORY(TYPE) \
53: (TREE_CODE (TYPE) == RECORD_TYPE || TREE_CODE(TYPE) == UNION_TYPE)
54:
55: /* Define which macros to predefine. __svr4__ is our extension. */
56: /* This used to define X86, but [email protected] says that
57: is supposed to be defined optionally by user programs--not by default. */
58: #define CPP_PREDEFINES \
59: "-Di386 -Dunix -D__svr4__ -Asystem(unix) -Acpu(i386) -Amachine(i386)"
60:
1.1.1.2 ! root 61: /* If the host and target formats match, output the floats as hex. */
! 62: #if HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT
! 63: #if defined (HOST_WORDS_BIG_ENDIAN) == WORDS_BIG_ENDIAN
! 64: /* This is how to output assembly code to define a `float' constant.
! 65: We always have to use a .long pseudo-op to do this because the native
! 66: SVR4 ELF assembler is buggy and it generates incorrect values when we
! 67: try to use the .float pseudo-op instead. */
! 68:
! 69: #undef ASM_OUTPUT_FLOAT
! 70: #define ASM_OUTPUT_FLOAT(FILE,VALUE) \
! 71: do { long value; \
! 72: REAL_VALUE_TO_TARGET_SINGLE ((VALUE), value); \
! 73: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value); \
! 74: } while (0)
! 75:
! 76: /* This is how to output assembly code to define a `double' constant.
! 77: We always have to use a pair of .long pseudo-ops to do this because
! 78: the native SVR4 ELF assembler is buggy and it generates incorrect
! 79: values when we try to use the the .double pseudo-op instead. */
! 80:
! 81: #undef ASM_OUTPUT_DOUBLE
! 82: #define ASM_OUTPUT_DOUBLE(FILE,VALUE) \
! 83: do { long value[2]; \
! 84: REAL_VALUE_TO_TARGET_DOUBLE ((VALUE), value); \
! 85: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \
! 86: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \
! 87: } while (0)
! 88: #endif /* word order matches */
! 89: #endif /* HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT */
! 90:
1.1 root 91: /* Output at beginning of assembler file. */
92: /* The .file command should always begin the output. */
93:
94: #undef ASM_FILE_START
95: #define ASM_FILE_START(FILE) \
96: do { \
97: output_file_directive (FILE, main_input_filename); \
98: fprintf (FILE, "\t.version\t\"01.01\"\n"); \
99: } while (0)
100:
101: /* Define the register numbers to be used in Dwarf debugging information.
102: The SVR4 reference port C compiler uses the following register numbers
103: in its Dwarf output code:
104:
1.1.1.2 ! root 105: 0 for %eax (gnu regno = 0)
! 106: 1 for %ecx (gnu regno = 2)
! 107: 2 for %edx (gnu regno = 1)
! 108: 3 for %ebx (gnu regno = 3)
! 109: 4 for %esp (gnu regno = 7)
! 110: 5 for %ebp (gnu regno = 6)
! 111: 6 for %esi (gnu regno = 4)
! 112: 7 for %edi (gnu regno = 5)
! 113:
! 114: The following three DWARF register numbers are never generated by
! 115: the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
! 116: believes these numbers have these meanings.
! 117:
! 118: 8 for %eip (no gnu equivalent)
! 119: 9 for %eflags (no gnu equivalent)
! 120: 10 for %trapno (no gnu equivalent)
! 121:
! 122: It is not at all clear how we should number the FP stack registers
! 123: for the x86 architecture. If the version of SDB on x86/svr4 were
! 124: a bit less brain dead with respect to floating-point then we would
! 125: have a precedent to follow with respect to DWARF register numbers
! 126: for x86 FP registers, but the SDB on x86/svr4 is so completely
! 127: broken with respect to FP registers that it is hardly worth thinking
! 128: of it as something to strive for compatability with.
! 129:
! 130: The verison of x86/svr4 SDB I have at the moment does (partially)
! 131: seem to believe that DWARF register number 11 is associated with
! 132: the x86 register %st(0), but that's about all. Higher DWARF
! 133: register numbers don't seem to be associated with anything in
! 134: particular, and even for DWARF regno 11, SDB only seems to under-
! 135: stand that it should say that a variable lives in %st(0) (when
! 136: asked via an `=' command) if we said it was in DWARF regno 11,
! 137: but SDB still prints garbage when asked for the value of the
! 138: variable in question (via a `/' command).
! 139:
! 140: (Also note that the labels SDB prints for various FP stack regs
! 141: when doing an `x' command are all wrong.)
! 142:
! 143: Note that these problems generally don't affect the native SVR4
! 144: C compiler because it doesn't allow the use of -O with -g and
! 145: because when it is *not* optimizing, it allocates a memory
! 146: location for each floating-point variable, and the memory
! 147: location is what gets described in the DWARF AT_location
! 148: attribute for the variable in question.
! 149:
! 150: Regardless of the severe mental illness of the x86/svr4 SDB, we
! 151: do something sensible here and we use the following DWARF
! 152: register numbers. Note that these are all stack-top-relative
! 153: numbers.
! 154:
! 155: 11 for %st(0) (gnu regno = 8)
! 156: 12 for %st(1) (gnu regno = 9)
! 157: 13 for %st(2) (gnu regno = 10)
! 158: 14 for %st(3) (gnu regno = 11)
! 159: 15 for %st(4) (gnu regno = 12)
! 160: 16 for %st(5) (gnu regno = 13)
! 161: 17 for %st(6) (gnu regno = 14)
! 162: 18 for %st(7) (gnu regno = 15)
1.1 root 163: */
164:
165: #undef DBX_REGISTER_NUMBER
166: #define DBX_REGISTER_NUMBER(n) \
167: ((n) == 0 ? 0 \
168: : (n) == 1 ? 2 \
169: : (n) == 2 ? 1 \
170: : (n) == 3 ? 3 \
171: : (n) == 4 ? 6 \
172: : (n) == 5 ? 7 \
173: : (n) == 6 ? 5 \
174: : (n) == 7 ? 4 \
1.1.1.2 ! root 175: : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
1.1 root 176: : (abort (), 0))
177:
178: /* The routine used to output sequences of byte values. We use a special
179: version of this for most svr4 targets because doing so makes the
180: generated assembly code more compact (and thus faster to assemble)
181: as well as more readable. Note that if we find subparts of the
182: character sequence which end with NUL (and which are shorter than
183: STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING. */
184:
185: #undef ASM_OUTPUT_ASCII
186: #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \
187: do \
188: { \
189: register unsigned char *_ascii_bytes = (unsigned char *) (STR); \
190: register unsigned char *limit = _ascii_bytes + (LENGTH); \
191: register unsigned bytes_in_chunk = 0; \
192: for (; _ascii_bytes < limit; _ascii_bytes++) \
193: { \
194: register unsigned char *p; \
195: if (bytes_in_chunk >= 64) \
196: { \
197: fputc ('\n', (FILE)); \
198: bytes_in_chunk = 0; \
199: } \
200: for (p = _ascii_bytes; p < limit && *p != '\0'; p++) \
201: continue; \
202: if (p < limit && (p - _ascii_bytes) <= STRING_LIMIT) \
203: { \
204: if (bytes_in_chunk > 0) \
205: { \
206: fputc ('\n', (FILE)); \
207: bytes_in_chunk = 0; \
208: } \
209: ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes); \
210: _ascii_bytes = p; \
211: } \
212: else \
213: { \
214: if (bytes_in_chunk == 0) \
215: fprintf ((FILE), "\t.byte\t"); \
216: else \
217: fputc (',', (FILE)); \
218: fprintf ((FILE), "0x%02x", *_ascii_bytes); \
219: bytes_in_chunk += 5; \
220: } \
221: } \
222: if (bytes_in_chunk > 0) \
223: fprintf ((FILE), "\n"); \
224: } \
225: while (0)
226:
227: /* This is how to output an element of a case-vector that is relative.
228: This is only used for PIC code. See comments by the `casesi' insn in
229: i386.md for an explanation of the expression this outputs. */
230:
231: #undef ASM_OUTPUT_ADDR_DIFF_ELT
232: #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, VALUE, REL) \
233: fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
234:
235: /* Indicate that jump tables go in the text section. This is
236: necessary when compiling PIC code. */
237:
238: #define JUMP_TABLES_IN_TEXT_SECTION
239:
240: /* Biggest alignment that any structure field can require on this
241: machine, in bits. If packing is in effect, this can be smaller than
242: normal. */
243:
244: #define BIGGEST_FIELD_ALIGNMENT \
245: (maximum_field_alignment ? maximum_field_alignment : 32)
246:
247: extern int maximum_field_alignment;
248:
249: /* If bit field type is int, don't let it cross an int,
250: and give entire struct the alignment of an int. */
251: /* Required on the 386 since it doesn't have bitfield insns. */
252: /* If packing is in effect, then the type doesn't matter. */
253:
254: #undef PCC_BITFIELD_TYPE_MATTERS
255: #define PCC_BITFIELD_TYPE_MATTERS (maximum_field_alignment == 0)
256:
257: /* Code to handle #pragma directives. The interface is a bit messy,
258: but there's no simpler way to do this while still using yylex. */
259: #define HANDLE_PRAGMA(FILE) \
260: do { \
261: while (c == ' ' || c == '\t') \
262: c = getc (FILE); \
263: if (c == '\n' || c == EOF) \
264: { \
265: handle_pragma_token (0, 0); \
266: return c; \
267: } \
268: ungetc (c, FILE); \
269: switch (yylex ()) \
270: { \
271: case IDENTIFIER: \
272: case TYPENAME: \
273: case STRING: \
274: case CONSTANT: \
275: handle_pragma_token (token_buffer, yylval.ttype); \
276: break; \
277: default: \
278: handle_pragma_token (token_buffer, 0); \
279: } \
280: if (nextchar >= 0) \
281: c = nextchar, nextchar = -1; \
282: else \
283: c = getc (FILE); \
284: } while (1)
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