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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/i386.h" /* Base i386 target machine definitions */
23: #include "i386/att.h" /* Use the i386 AT&T assembler syntax */
24: #include "svr4.h" /* Definitions common to all SVR4 targets */
25:
26: #undef TARGET_VERSION
27: #define TARGET_VERSION fprintf (stderr, " (i386 System V Release 4)");
28:
29: /* The svr4 ABI for the i386 says that records and unions are returned
30: in memory. */
31:
32: #undef RETURN_IN_MEMORY
33: #define RETURN_IN_MEMORY(TYPE) \
34: (TYPE_MODE (TYPE) == BLKmode)
35:
36: /* Define which macros to predefine. __svr4__ is our extension. */
37: /* This used to define X86, but [email protected] says that
38: is supposed to be defined optionally by user programs--not by default. */
39: #define CPP_PREDEFINES \
40: "-Di386 -Dunix -D__svr4__ -Asystem(unix) -Asystem(svr4) -Acpu(i386) -Amachine(i386)"
41:
42: /* This is how to output assembly code to define a `float' constant.
43: We always have to use a .long pseudo-op to do this because the native
44: SVR4 ELF assembler is buggy and it generates incorrect values when we
45: try to use the .float pseudo-op instead. */
46:
47: #undef ASM_OUTPUT_FLOAT
48: #define ASM_OUTPUT_FLOAT(FILE,VALUE) \
49: do { long value; \
50: REAL_VALUE_TO_TARGET_SINGLE ((VALUE), value); \
51: if (sizeof (int) == sizeof (long)) \
52: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value); \
53: else \
54: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value); \
55: } while (0)
56:
57: /* This is how to output assembly code to define a `double' constant.
58: We always have to use a pair of .long pseudo-ops to do this because
59: the native SVR4 ELF assembler is buggy and it generates incorrect
60: values when we try to use the the .double pseudo-op instead. */
61:
62: #undef ASM_OUTPUT_DOUBLE
63: #define ASM_OUTPUT_DOUBLE(FILE,VALUE) \
64: do { long value[2]; \
65: REAL_VALUE_TO_TARGET_DOUBLE ((VALUE), value); \
66: if (sizeof (int) == sizeof (long)) \
67: { \
68: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \
69: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \
70: } \
71: else \
72: { \
73: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[0]); \
74: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[1]); \
75: } \
76: } while (0)
77:
78:
79: #undef ASM_OUTPUT_LONG_DOUBLE
80: #define ASM_OUTPUT_LONG_DOUBLE(FILE,VALUE) \
81: do { long value[3]; \
82: REAL_VALUE_TO_TARGET_LONG_DOUBLE ((VALUE), value); \
83: if (sizeof (int) == sizeof (long)) \
84: { \
85: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[0]); \
86: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[1]); \
87: fprintf((FILE), "%s\t0x%x\n", ASM_LONG, value[2]); \
88: } \
89: else \
90: { \
91: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[0]); \
92: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[1]); \
93: fprintf((FILE), "%s\t0x%lx\n", ASM_LONG, value[2]); \
94: } \
95: } while (0)
96:
97: /* Output at beginning of assembler file. */
98: /* The .file command should always begin the output. */
99:
100: #undef ASM_FILE_START
101: #define ASM_FILE_START(FILE) \
102: do { \
103: output_file_directive (FILE, main_input_filename); \
104: fprintf (FILE, "\t.version\t\"01.01\"\n"); \
105: } while (0)
106:
107: /* Define the register numbers to be used in Dwarf debugging information.
108: The SVR4 reference port C compiler uses the following register numbers
109: in its Dwarf output code:
110:
111: 0 for %eax (gnu regno = 0)
112: 1 for %ecx (gnu regno = 2)
113: 2 for %edx (gnu regno = 1)
114: 3 for %ebx (gnu regno = 3)
115: 4 for %esp (gnu regno = 7)
116: 5 for %ebp (gnu regno = 6)
117: 6 for %esi (gnu regno = 4)
118: 7 for %edi (gnu regno = 5)
119:
120: The following three DWARF register numbers are never generated by
121: the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
122: believes these numbers have these meanings.
123:
124: 8 for %eip (no gnu equivalent)
125: 9 for %eflags (no gnu equivalent)
126: 10 for %trapno (no gnu equivalent)
127:
128: It is not at all clear how we should number the FP stack registers
129: for the x86 architecture. If the version of SDB on x86/svr4 were
130: a bit less brain dead with respect to floating-point then we would
131: have a precedent to follow with respect to DWARF register numbers
132: for x86 FP registers, but the SDB on x86/svr4 is so completely
133: broken with respect to FP registers that it is hardly worth thinking
134: of it as something to strive for compatibility with.
135:
136: The verison of x86/svr4 SDB I have at the moment does (partially)
137: seem to believe that DWARF register number 11 is associated with
138: the x86 register %st(0), but that's about all. Higher DWARF
139: register numbers don't seem to be associated with anything in
140: particular, and even for DWARF regno 11, SDB only seems to under-
141: stand that it should say that a variable lives in %st(0) (when
142: asked via an `=' command) if we said it was in DWARF regno 11,
143: but SDB still prints garbage when asked for the value of the
144: variable in question (via a `/' command).
145:
146: (Also note that the labels SDB prints for various FP stack regs
147: when doing an `x' command are all wrong.)
148:
149: Note that these problems generally don't affect the native SVR4
150: C compiler because it doesn't allow the use of -O with -g and
151: because when it is *not* optimizing, it allocates a memory
152: location for each floating-point variable, and the memory
153: location is what gets described in the DWARF AT_location
154: attribute for the variable in question.
155:
156: Regardless of the severe mental illness of the x86/svr4 SDB, we
157: do something sensible here and we use the following DWARF
158: register numbers. Note that these are all stack-top-relative
159: numbers.
160:
161: 11 for %st(0) (gnu regno = 8)
162: 12 for %st(1) (gnu regno = 9)
163: 13 for %st(2) (gnu regno = 10)
164: 14 for %st(3) (gnu regno = 11)
165: 15 for %st(4) (gnu regno = 12)
166: 16 for %st(5) (gnu regno = 13)
167: 17 for %st(6) (gnu regno = 14)
168: 18 for %st(7) (gnu regno = 15)
169: */
170:
171: #undef DBX_REGISTER_NUMBER
172: #define DBX_REGISTER_NUMBER(n) \
173: ((n) == 0 ? 0 \
174: : (n) == 1 ? 2 \
175: : (n) == 2 ? 1 \
176: : (n) == 3 ? 3 \
177: : (n) == 4 ? 6 \
178: : (n) == 5 ? 7 \
179: : (n) == 6 ? 5 \
180: : (n) == 7 ? 4 \
181: : ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
182: : (-1))
183:
184: /* The routine used to output sequences of byte values. We use a special
185: version of this for most svr4 targets because doing so makes the
186: generated assembly code more compact (and thus faster to assemble)
187: as well as more readable. Note that if we find subparts of the
188: character sequence which end with NUL (and which are shorter than
189: STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING. */
190:
191: #undef ASM_OUTPUT_ASCII
192: #define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \
193: do \
194: { \
195: register unsigned char *_ascii_bytes = (unsigned char *) (STR); \
196: register unsigned char *limit = _ascii_bytes + (LENGTH); \
197: register unsigned bytes_in_chunk = 0; \
198: for (; _ascii_bytes < limit; _ascii_bytes++) \
199: { \
200: register unsigned char *p; \
201: if (bytes_in_chunk >= 64) \
202: { \
203: fputc ('\n', (FILE)); \
204: bytes_in_chunk = 0; \
205: } \
206: for (p = _ascii_bytes; p < limit && *p != '\0'; p++) \
207: continue; \
208: if (p < limit && (p - _ascii_bytes) <= STRING_LIMIT) \
209: { \
210: if (bytes_in_chunk > 0) \
211: { \
212: fputc ('\n', (FILE)); \
213: bytes_in_chunk = 0; \
214: } \
215: ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes); \
216: _ascii_bytes = p; \
217: } \
218: else \
219: { \
220: if (bytes_in_chunk == 0) \
221: fprintf ((FILE), "\t.byte\t"); \
222: else \
223: fputc (',', (FILE)); \
224: fprintf ((FILE), "0x%02x", *_ascii_bytes); \
225: bytes_in_chunk += 5; \
226: } \
227: } \
228: if (bytes_in_chunk > 0) \
229: fprintf ((FILE), "\n"); \
230: } \
231: while (0)
232:
233: /* This is how to output an element of a case-vector that is relative.
234: This is only used for PIC code. See comments by the `casesi' insn in
235: i386.md for an explanation of the expression this outputs. */
236:
237: #undef ASM_OUTPUT_ADDR_DIFF_ELT
238: #define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, VALUE, REL) \
239: fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
240:
241: /* Indicate that jump tables go in the text section. This is
242: necessary when compiling PIC code. */
243:
244: #define JUMP_TABLES_IN_TEXT_SECTION
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