254 lines
9.0 KiB
C
254 lines
9.0 KiB
C
/* Target definitions for GNU compiler for Intel 80386 running System V.4
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Copyright (C) 1991 Free Software Foundation, Inc.
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Written by Ron Guilmette (rfg@ncd.com).
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "i386.h" /* Base i386 target machine definitions */
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#include "att386.h" /* Use the i386 AT&T assembler syntax */
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#include "svr4.h" /* Definitions common to all SVR4 targets */
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#undef TARGET_VERSION
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#define TARGET_VERSION fprintf (stderr, " (i386 System V Release 4)");
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/* By default, target has a 80387. */
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#define TARGET_DEFAULT 1
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/* Machines that use the AT&T assembler syntax
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also return floating point values in an FP register. */
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/* Define how to find the value returned by a function.
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VALTYPE is the data type of the value (as a tree).
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If the precise function being called is known, FUNC is its FUNCTION_DECL;
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otherwise, FUNC is 0. */
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#define VALUE_REGNO(MODE) \
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(((MODE) == SFmode || (MODE) == DFmode) ? FIRST_FLOAT_REG : 0)
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/* 1 if N is a possible register number for a function value. */
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#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0 || (N)== FIRST_FLOAT_REG)
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/* The svr4 ABI for the i386 says that records and unions are returned
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in memory. */
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#undef RETURN_IN_MEMORY
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#define RETURN_IN_MEMORY(TYPE) \
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(TREE_CODE (TYPE) == RECORD_TYPE || TREE_CODE(TYPE) == UNION_TYPE)
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/* Define which macros to predefine. __svr4__ is our extension. */
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/* This used to define X86, but james@bigtex.cactus.org says that
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is supposed to be defined optionally by user programs--not by default. */
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#define CPP_PREDEFINES \
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"-Di386 -Dunix -D__svr4__ -Asystem(unix) -Acpu(i386) -Amachine(i386)"
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/* Output at beginning of assembler file. */
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/* The .file command should always begin the output. */
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#undef ASM_FILE_START
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#define ASM_FILE_START(FILE) \
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do { \
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output_file_directive (FILE, main_input_filename); \
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fprintf (FILE, "\t.version\t\"01.01\"\n"); \
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} while (0)
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/* Define the register numbers to be used in Dwarf debugging information.
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The SVR4 reference port C compiler uses the following register numbers
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in its Dwarf output code:
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0 for %eax (gnu regno = 0)
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1 for %ecx (gnu regno = 2)
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2 for %edx (gnu regno = 1)
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3 for %ebx (gnu regno = 3)
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4 for %esp (gnu regno = 7)
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5 for %ebp (gnu regno = 6)
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6 for %esi (gnu regno = 4)
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7 for %edi (gnu regno = 5)
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The following three DWARF register numbers are never generated by
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the SVR4 C compiler or by the GNU compilers, but SDB on x86/svr4
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believes these numbers have these meanings.
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8 for %eip (no gnu equivalent)
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9 for %eflags (no gnu equivalent)
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10 for %trapno (no gnu equivalent)
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It is not at all clear how we should number the FP stack registers
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for the x86 architecture. If the version of SDB on x86/svr4 were
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a bit less brain dead with respect to floating-point then we would
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have a precedent to follow with respect to DWARF register numbers
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for x86 FP registers, but the SDB on x86/svr4 is so completely
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broken with respect to FP registers that it is hardly worth thinking
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of it as something to strive for compatability with.
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The verison of x86/svr4 SDB I have at the moment does (partially)
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seem to believe that DWARF register number 11 is associated with
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the x86 register %st(0), but that's about all. Higher DWARF
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register numbers don't seem to be associated with anything in
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particular, and even for DWARF regno 11, SDB only seems to under-
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stand that it should say that a variable lives in %st(0) (when
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asked via an `=' command) if we said it was in DWARF regno 11,
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but SDB still prints garbage when asked for the value of the
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variable in question (via a `/' command).
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(Also note that the labels SDB prints for various FP stack regs
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when doing an `x' command are all wrong.)
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Note that these problems generally don't affect the native SVR4
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C compiler because it doesn't allow the use of -O with -g and
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because when it is *not* optimizing, it allocates a memory
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location for each floating-point variable, and the memory
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location is what gets described in the DWARF AT_location
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attribute for the variable in question.
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Regardless of the severe mental illness of the x86/svr4 SDB, we
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do something sensible here and we use the following DWARF
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register numbers. Note that these are all stack-top-relative
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numbers.
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11 for %st(0) (gnu regno = 8)
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12 for %st(1) (gnu regno = 9)
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13 for %st(2) (gnu regno = 10)
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14 for %st(3) (gnu regno = 11)
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15 for %st(4) (gnu regno = 12)
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16 for %st(5) (gnu regno = 13)
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17 for %st(6) (gnu regno = 14)
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18 for %st(7) (gnu regno = 15)
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*/
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#undef DBX_REGISTER_NUMBER
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#define DBX_REGISTER_NUMBER(n) \
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((n) == 0 ? 0 \
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: (n) == 1 ? 2 \
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: (n) == 2 ? 1 \
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: (n) == 3 ? 3 \
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: (n) == 4 ? 6 \
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: (n) == 5 ? 7 \
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: (n) == 6 ? 5 \
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: (n) == 7 ? 4 \
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: ((n) >= FIRST_STACK_REG && (n) <= LAST_STACK_REG) ? (n)+3 \
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: (abort (), 0))
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/* The routine used to output sequences of byte values. We use a special
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version of this for most svr4 targets because doing so makes the
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generated assembly code more compact (and thus faster to assemble)
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as well as more readable. Note that if we find subparts of the
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character sequence which end with NUL (and which are shorter than
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STRING_LIMIT) we output those using ASM_OUTPUT_LIMITED_STRING. */
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#undef ASM_OUTPUT_ASCII
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#define ASM_OUTPUT_ASCII(FILE, STR, LENGTH) \
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do \
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{ \
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register unsigned char *_ascii_bytes = (unsigned char *) (STR); \
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register unsigned char *limit = _ascii_bytes + (LENGTH); \
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register unsigned bytes_in_chunk = 0; \
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for (; _ascii_bytes < limit; _ascii_bytes++) \
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{ \
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register unsigned char *p; \
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if (bytes_in_chunk >= 64) \
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{ \
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fputc ('\n', (FILE)); \
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bytes_in_chunk = 0; \
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} \
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for (p = _ascii_bytes; p < limit && *p != '\0'; p++) \
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continue; \
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if (p < limit && (p - _ascii_bytes) <= STRING_LIMIT) \
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{ \
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if (bytes_in_chunk > 0) \
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{ \
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fputc ('\n', (FILE)); \
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bytes_in_chunk = 0; \
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} \
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ASM_OUTPUT_LIMITED_STRING ((FILE), _ascii_bytes); \
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_ascii_bytes = p; \
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} \
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else \
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{ \
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if (bytes_in_chunk == 0) \
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fprintf ((FILE), "\t.byte\t"); \
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else \
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fputc (',', (FILE)); \
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fprintf ((FILE), "0x%02x", *_ascii_bytes); \
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bytes_in_chunk += 5; \
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} \
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} \
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if (bytes_in_chunk > 0) \
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fprintf ((FILE), "\n"); \
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} \
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while (0)
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/* This is how to output an element of a case-vector that is relative.
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This is only used for PIC code. See comments by the `casesi' insn in
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i386.md for an explanation of the expression this outputs. */
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#undef ASM_OUTPUT_ADDR_DIFF_ELT
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#define ASM_OUTPUT_ADDR_DIFF_ELT(FILE, VALUE, REL) \
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fprintf (FILE, "\t.long _GLOBAL_OFFSET_TABLE_+[.-%s%d]\n", LPREFIX, VALUE)
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/* Indicate that jump tables go in the text section. This is
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necessary when compiling PIC code. */
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#define JUMP_TABLES_IN_TEXT_SECTION
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/* Biggest alignment that any structure field can require on this
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machine, in bits. If packing is in effect, this can be smaller than
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normal. */
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#define BIGGEST_FIELD_ALIGNMENT \
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(maximum_field_alignment ? maximum_field_alignment : 32)
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extern int maximum_field_alignment;
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/* If bit field type is int, don't let it cross an int,
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and give entire struct the alignment of an int. */
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/* Required on the 386 since it doesn't have bitfield insns. */
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/* If packing is in effect, then the type doesn't matter. */
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#undef PCC_BITFIELD_TYPE_MATTERS
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#define PCC_BITFIELD_TYPE_MATTERS (maximum_field_alignment == 0)
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/* Code to handle #pragma directives. The interface is a bit messy,
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but there's no simpler way to do this while still using yylex. */
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#define HANDLE_PRAGMA(FILE) \
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do { \
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while (c == ' ' || c == '\t') \
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c = getc (FILE); \
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if (c == '\n' || c == EOF) \
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{ \
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handle_pragma_token (0, 0); \
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return c; \
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} \
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ungetc (c, FILE); \
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switch (yylex ()) \
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{ \
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case IDENTIFIER: \
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case TYPENAME: \
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case STRING: \
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case CONSTANT: \
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handle_pragma_token (token_buffer, yylval.ttype); \
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break; \
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default: \
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handle_pragma_token (token_buffer, 0); \
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} \
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if (nextchar >= 0) \
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c = nextchar, nextchar = -1; \
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else \
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c = getc (FILE); \
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} while (1)
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