1 /* Target definitions for GNU compiler for Intel 80386 running System V.4
2 Copyright (C) 1991 Free Software Foundation, Inc.
4 Written by Ron Guilmette (rfg@netcom.com).
6 This file is part of GNU CC.
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)
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.
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, 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
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 */
28 #define TARGET_VERSION fprintf (stderr, " (i386 System V Release 4)");
30 /* The svr4 ABI for the i386 says that records and unions are returned
33 #undef RETURN_IN_MEMORY
34 #define RETURN_IN_MEMORY(TYPE) \
35 (TYPE_MODE (TYPE) == BLKmode)
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)"
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. */
48 #undef ASM_OUTPUT_FLOAT
49 #define ASM_OUTPUT_FLOAT(FILE,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); \
55 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value); \
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 the .double pseudo-op instead. */
63 #undef ASM_OUTPUT_DOUBLE
64 #define ASM_OUTPUT_DOUBLE(FILE,VALUE) \
66 REAL_VALUE_TO_TARGET_DOUBLE ((VALUE), value); \
67 if (sizeof (int) == sizeof (long)) \
69 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \
70 fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \
74 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[0]); \
75 fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[1]); \
80 #undef ASM_OUTPUT_LONG_DOUBLE
81 #define ASM_OUTPUT_LONG_DOUBLE(FILE,VALUE) \
83 REAL_VALUE_TO_TARGET_LONG_DOUBLE ((VALUE), value); \
84 if (sizeof (int) == sizeof (long)) \
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]); \
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]); \
98 /* Output at beginning of assembler file. */
99 /* The .file command should always begin the output. */
101 #undef ASM_FILE_START
102 #define ASM_FILE_START(FILE) \
104 output_file_directive (FILE, main_input_filename); \
105 fprintf (FILE, "\t.version\t\"01.01\"\n"); \
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:
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)
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.
125 8 for %eip (no gnu equivalent)
126 9 for %eflags (no gnu equivalent)
127 10 for %trapno (no gnu equivalent)
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.
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).
147 (Also note that the labels SDB prints for various FP stack regs
148 when doing an `x' command are all wrong.)
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.
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
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)
172 #undef DBX_REGISTER_NUMBER
173 #define DBX_REGISTER_NUMBER(n) \
182 : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
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. */
192 #undef ASM_OUTPUT_ASCII
193 #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \
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++) \
201 register unsigned char *p; \
202 if (bytes_in_chunk >= 64) \
204 fputc ('\n', (FILE)); \
205 bytes_in_chunk = 0; \
207 for (p = _ascii_bytes; p < limit && *p != '\0'; p++) \
209 if (p < limit && (p - _ascii_bytes) <= STRING_LIMIT) \
211 if (bytes_in_chunk > 0) \
213 fputc ('\n', (FILE)); \
214 bytes_in_chunk = 0; \
216 ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes); \
221 if (bytes_in_chunk == 0) \
222 fprintf ((FILE), "\t.byte\t"); \
224 fputc (',', (FILE)); \
225 fprintf ((FILE), "0x%02x", *_ascii_bytes); \
226 bytes_in_chunk += 5; \
229 if (bytes_in_chunk > 0) \
230 fprintf ((FILE), "\n"); \
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. */
238 #undef ASM_OUTPUT_ADDR_DIFF_ELT
239 #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, VALUE, REL) \
240 fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
242 /* Indicate that jump tables go in the text section. This is
243 necessary when compiling PIC code. */
245 #define JUMP_TABLES_IN_TEXT_SECTION