sysv4.h revision 50397
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 (rfg@netcom.com). 5 6This file is part of GNU CC. 7 8GNU CC is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 2, or (at your option) 11any later version. 12 13GNU CC is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with GNU CC; see the file COPYING. If not, write to 20the Free Software Foundation, 59 Temple Place - Suite 330, 21Boston, MA 02111-1307, USA. */ 22 23#include "i386/i386.h" /* Base i386 target machine definitions */ 24#include "i386/att.h" /* Use the i386 AT&T assembler syntax */ 25#include "svr4.h" /* Definitions common to all SVR4 targets */ 26 27#undef TARGET_VERSION 28#define TARGET_VERSION fprintf (stderr, " (i386 System V Release 4)"); 29 30/* The svr4 ABI for the i386 says that records and unions are returned 31 in memory. */ 32 33#undef RETURN_IN_MEMORY 34#define RETURN_IN_MEMORY(TYPE) \ 35 (TYPE_MODE (TYPE) == BLKmode) 36 37/* Define which macros to predefine. __svr4__ is our extension. */ 38/* This used to define X86, but james@bigtex.cactus.org says that 39 is supposed to be defined optionally by user programs--not by default. */ 40#define CPP_PREDEFINES \ 41 "-Di386 -Dunix -D__svr4__ -Asystem(unix) -Asystem(svr4) -Acpu(i386) -Amachine(i386)" 42 43/* This is how to output assembly code to define a `float' constant. 44 We always have to use a .long pseudo-op to do this because the native 45 SVR4 ELF assembler is buggy and it generates incorrect values when we 46 try to use the .float pseudo-op instead. */ 47 48#undef ASM_OUTPUT_FLOAT 49#define ASM_OUTPUT_FLOAT(FILE,VALUE) \ 50do { long value; \ 51 REAL_VALUE_TO_TARGET_SINGLE ((VALUE), value); \ 52 if (sizeof (int) == sizeof (long)) \ 53 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value); \ 54 else \ 55 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value); \ 56 } while (0) 57 58/* This is how to output assembly code to define a `double' constant. 59 We always have to use a pair of .long pseudo-ops to do this because 60 the native SVR4 ELF assembler is buggy and it generates incorrect 61 values when we try to use the .double pseudo-op instead. */ 62 63#undef ASM_OUTPUT_DOUBLE 64#define ASM_OUTPUT_DOUBLE(FILE,VALUE) \ 65do { long value[2]; \ 66 REAL_VALUE_TO_TARGET_DOUBLE ((VALUE), value); \ 67 if (sizeof (int) == sizeof (long)) \ 68 { \ 69 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \ 70 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \ 71 } \ 72 else \ 73 { \ 74 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[0]); \ 75 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[1]); \ 76 } \ 77 } while (0) 78 79 80#undef ASM_OUTPUT_LONG_DOUBLE 81#define ASM_OUTPUT_LONG_DOUBLE(FILE,VALUE) \ 82do { long value[3]; \ 83 REAL_VALUE_TO_TARGET_LONG_DOUBLE ((VALUE), value); \ 84 if (sizeof (int) == sizeof (long)) \ 85 { \ 86 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \ 87 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \ 88 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[2]); \ 89 } \ 90 else \ 91 { \ 92 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[0]); \ 93 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[1]); \ 94 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[2]); \ 95 } \ 96 } while (0) 97 98/* Output at beginning of assembler file. */ 99/* The .file command should always begin the output. */ 100 101#undef ASM_FILE_START 102#define ASM_FILE_START(FILE) \ 103 do { \ 104 output_file_directive (FILE, main_input_filename); \ 105 fprintf (FILE, "\t.version\t\"01.01\"\n"); \ 106 } while (0) 107 108/* Define the register numbers to be used in Dwarf debugging information. 109 The SVR4 reference port C compiler uses the following register numbers 110 in its Dwarf output code: 111 112 0 for %eax (gnu regno = 0) 113 1 for %ecx (gnu regno = 2) 114 2 for %edx (gnu regno = 1) 115 3 for %ebx (gnu regno = 3) 116 4 for %esp (gnu regno = 7) 117 5 for %ebp (gnu regno = 6) 118 6 for %esi (gnu regno = 4) 119 7 for %edi (gnu regno = 5) 120 121 The following three DWARF register numbers are never generated by 122 the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4 123 believes these numbers have these meanings. 124 125 8 for %eip (no gnu equivalent) 126 9 for %eflags (no gnu equivalent) 127 10 for %trapno (no gnu equivalent) 128 129 It is not at all clear how we should number the FP stack registers 130 for the x86 architecture. If the version of SDB on x86/svr4 were 131 a bit less brain dead with respect to floating-point then we would 132 have a precedent to follow with respect to DWARF register numbers 133 for x86 FP registers, but the SDB on x86/svr4 is so completely 134 broken with respect to FP registers that it is hardly worth thinking 135 of it as something to strive for compatibility with. 136 137 The version of x86/svr4 SDB I have at the moment does (partially) 138 seem to believe that DWARF register number 11 is associated with 139 the x86 register %st(0), but that's about all. Higher DWARF 140 register numbers don't seem to be associated with anything in 141 particular, and even for DWARF regno 11, SDB only seems to under- 142 stand that it should say that a variable lives in %st(0) (when 143 asked via an `=' command) if we said it was in DWARF regno 11, 144 but SDB still prints garbage when asked for the value of the 145 variable in question (via a `/' command). 146 147 (Also note that the labels SDB prints for various FP stack regs 148 when doing an `x' command are all wrong.) 149 150 Note that these problems generally don't affect the native SVR4 151 C compiler because it doesn't allow the use of -O with -g and 152 because when it is *not* optimizing, it allocates a memory 153 location for each floating-point variable, and the memory 154 location is what gets described in the DWARF AT_location 155 attribute for the variable in question. 156 157 Regardless of the severe mental illness of the x86/svr4 SDB, we 158 do something sensible here and we use the following DWARF 159 register numbers. Note that these are all stack-top-relative 160 numbers. 161 162 11 for %st(0) (gnu regno = 8) 163 12 for %st(1) (gnu regno = 9) 164 13 for %st(2) (gnu regno = 10) 165 14 for %st(3) (gnu regno = 11) 166 15 for %st(4) (gnu regno = 12) 167 16 for %st(5) (gnu regno = 13) 168 17 for %st(6) (gnu regno = 14) 169 18 for %st(7) (gnu regno = 15) 170*/ 171 172#undef DBX_REGISTER_NUMBER 173#define DBX_REGISTER_NUMBER(n) \ 174((n) == 0 ? 0 \ 175 : (n) == 1 ? 2 \ 176 : (n) == 2 ? 1 \ 177 : (n) == 3 ? 3 \ 178 : (n) == 4 ? 6 \ 179 : (n) == 5 ? 7 \ 180 : (n) == 6 ? 5 \ 181 : (n) == 7 ? 4 \ 182 : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \ 183 : (-1)) 184 185/* The routine used to output sequences of byte values. We use a special 186 version of this for most svr4 targets because doing so makes the 187 generated assembly code more compact (and thus faster to assemble) 188 as well as more readable. Note that if we find subparts of the 189 character sequence which end with NUL (and which are shorter than 190 STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING. */ 191 192#undef ASM_OUTPUT_ASCII 193#define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \ 194 do \ 195 { \ 196 register unsigned char *_ascii_bytes = (unsigned char *) (STR); \ 197 register unsigned char *limit = _ascii_bytes + (LENGTH); \ 198 register unsigned bytes_in_chunk = 0; \ 199 for (; _ascii_bytes < limit; _ascii_bytes++) \ 200 { \ 201 register unsigned char *p; \ 202 if (bytes_in_chunk >= 64) \ 203 { \ 204 fputc ('\n', (FILE)); \ 205 bytes_in_chunk = 0; \ 206 } \ 207 for (p = _ascii_bytes; p < limit && *p != '\0'; p++) \ 208 continue; \ 209 if (p < limit && (p - _ascii_bytes) <= STRING_LIMIT) \ 210 { \ 211 if (bytes_in_chunk > 0) \ 212 { \ 213 fputc ('\n', (FILE)); \ 214 bytes_in_chunk = 0; \ 215 } \ 216 ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes); \ 217 _ascii_bytes = p; \ 218 } \ 219 else \ 220 { \ 221 if (bytes_in_chunk == 0) \ 222 fprintf ((FILE), "\t.byte\t"); \ 223 else \ 224 fputc (',', (FILE)); \ 225 fprintf ((FILE), "0x%02x", *_ascii_bytes); \ 226 bytes_in_chunk += 5; \ 227 } \ 228 } \ 229 if (bytes_in_chunk > 0) \ 230 fprintf ((FILE), "\n"); \ 231 } \ 232 while (0) 233 234/* This is how to output an element of a case-vector that is relative. 235 This is only used for PIC code. See comments by the `casesi' insn in 236 i386.md for an explanation of the expression this outputs. */ 237 238#undef ASM_OUTPUT_ADDR_DIFF_ELT 239#define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, BODY, VALUE, REL) \ 240 fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE) 241 242/* Indicate that jump tables go in the text section. This is 243 necessary when compiling PIC code. */ 244 245#define JUMP_TABLES_IN_TEXT_SECTION (flag_pic) 246 247/* A C statement (sans semicolon) to output to the stdio stream 248 FILE the assembler definition of uninitialized global DECL named 249 NAME whose size is SIZE bytes and alignment is ALIGN bytes. 250 Try to use asm_output_aligned_bss to implement this macro. */ 251 252#define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \ 253 asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN) 254