184 lines
7.2 KiB
C
184 lines
7.2 KiB
C
/* Target definitions for GNU compiler for mc680x0 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) and Fred Fish (fnf@cygnus.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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/* Use SGS_* macros to control compilation in m68k.md */
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#define SGS_SWITCH_TABLES /* Different switch table handling */
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#include "m68ksgs.h" /* The m68k/SVR4 assembler is SGS based */
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#include "svr4.h" /* Pick up the generic SVR4 macros */
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/* See m68k.h. 7 means 68020 with 68881. */
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#ifndef TARGET_DEFAULT
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#define TARGET_DEFAULT (5 /*68020*/ + 2 /*68881*/)
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#endif
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/* Override the definition of NO_DOLLAR_IN_LABEL in svr4.h, for special
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g++ assembler names. When this is defined, g++ uses embedded '.'
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characters and some m68k assemblers have problems with this. The
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chances are much greater that any particular assembler will permit
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embedded '$' characters. */
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#undef NO_DOLLAR_IN_LABEL
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/* Define PCC_STATIC_STRUCT_RETURN if the convention on the target machine
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is to use the nonreentrant technique for returning structure and union
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values, as commonly implemented by the AT&T Portable C Compiler (PCC).
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When defined, the gcc option -fpcc-struct-return can be used to cause
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this form to be generated. When undefined, the option does nothing.
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For m68k SVR4, the convention is to use a reentrant technique compatible
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with the gcc default, so override the definition of this macro in m68k.h */
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#undef PCC_STATIC_STRUCT_RETURN
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/* Provide a set of pre-definitions and pre-assertions appropriate for
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the m68k running svr4. __svr4__ is our extension. */
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#define CPP_PREDEFINES \
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"-Dm68k -Dunix -D__svr4__ -Asystem(unix) -Acpu(m68k) -Amachine(m68k)"
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/* Test to see if the target includes a 68881 by default, and use CPP_SPEC
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to control whether or not __HAVE_68881__ is defined by default or not.
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If a 68881 is the default, gcc will use inline 68881 instructions, by
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predefining __HAVE_68881__, unless -msoft-float is specified.
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If a 68881 is not the default, gcc will only define __HAVE_68881__ if
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-m68881 is specified. */
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#if TARGET_DEFAULT & 2
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#define CPP_SPEC "%{!msoft-float:-D__HAVE_68881__}"
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#else
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#define CPP_SPEC "%{m68881:-D__HAVE_68881__}"
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#endif
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/* Output assembler code to FILE to increment profiler label # LABELNO
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for profiling a function entry. We override the definition in m68k.h
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and match the way the native m68k/SVR4 compiler does profiling, with the
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address of the profile counter in a1, not a0, and using bsr rather
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than jsr. */
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#undef FUNCTION_PROFILER
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#define FUNCTION_PROFILER(FILE, LABELNO) \
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asm_fprintf ((FILE), "\tlea.l\t(%LLP%d,%Rpc),%Ra1\n\tbsr\t_mcount\n", \
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(LABELNO))
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/* Local common symbols are declared to the assembler with ".lcomm" rather
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than ".bss", so override the definition in svr4.h */
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#undef BSS_ASM_OP
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#define BSS_ASM_OP ".lcomm"
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/* Register in which address to store a structure value is passed to a
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function. The default in m68k.h is a1. For m68k/SVR4 it is a0. */
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#undef STRUCT_VALUE_REGNUM
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#define STRUCT_VALUE_REGNUM 8
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#define ASM_COMMENT_START "#"
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#undef TYPE_OPERAND_FMT
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#define TYPE_OPERAND_FMT "@%s"
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/* Define how the m68k registers should be numbered for Dwarf output.
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The numbering provided here should be compatible with the native
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SVR4 SDB debugger in the m68k/SVR4 reference port, where d0-d7
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are 0-7, a0-a8 are 8-15, and fp0-fp7 are 16-23. */
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#define DBX_REGISTER_NUMBER(REGNO) (REGNO)
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/* The ASM_OUTPUT_SKIP macro is first defined in m68k.h, using ".skip".
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It is then overridden by m68ksgs.h to use ".space", and again by svr4.h
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to use ".zero". The m68k/SVR4 assembler uses ".space", so repeat the
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definition from m68ksgs.h here. Note that ASM_NO_SKIP_IN_TEXT is
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defined in m68ksgs.h, so we don't have to repeat it here. */
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#undef ASM_OUTPUT_SKIP
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#define ASM_OUTPUT_SKIP(FILE,SIZE) \
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fprintf (FILE, "\t%s %u\n", SPACE_ASM_OP, (SIZE))
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/* 1 if N is a possible register number for a function value.
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For m68k/SVR4 allow d0, a0, or fp0 as return registers, for integral,
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pointer, or floating types, respectively. Reject fp0 if not using a
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68881 coprocessor. */
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#undef FUNCTION_VALUE_REGNO_P
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#define FUNCTION_VALUE_REGNO_P(N) \
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((N) == 0 || (N) == 8 || (TARGET_68881 && (N) == 16))
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/* Define how to generate (in the callee) the output value of a function
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and how to find (in the caller) the value returned by a function. VALTYPE
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is the data type of the value (as a tree). If the precise function being
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called is known, FUNC is its FUNCTION_DECL; otherwise, FUNC is 0.
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For m68k/SVR4 generate the result in d0, a0, or fp0 as appropriate. */
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#undef FUNCTION_VALUE
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#define FUNCTION_VALUE(VALTYPE, FUNC) \
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(TREE_CODE (VALTYPE) == REAL_TYPE && TARGET_68881 \
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? gen_rtx (REG, TYPE_MODE (VALTYPE), 16) \
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: (TREE_CODE (VALTYPE) == POINTER_TYPE \
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? gen_rtx (REG, TYPE_MODE (VALTYPE), 8) \
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: gen_rtx (REG, TYPE_MODE (VALTYPE), 0)))
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/* For compatibility with the large body of existing code which does not
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always properly declare external functions returning pointer types, the
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m68k/SVR4 convention is to copy the value returned for pointer functions
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from a0 to d0 in the function epilogue, so that callers that have
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neglected to properly declare the callee can still find the correct return
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value. */
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extern int current_function_returns_pointer;
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#define FUNCTION_EXTRA_EPILOGUE(FILE, SIZE) \
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do { \
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if ((current_function_returns_pointer) && \
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! find_equiv_reg (0, get_last_insn (), 0, 0, 0, 8, Pmode)) \
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asm_fprintf (FILE, "\tmov.l %Ra0,%Rd0\n"); \
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} while (0);
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/* Define how to find the value returned by a library function assuming the
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value has mode MODE.
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For m68k/SVR4 look for integer values in d0, pointer values in d0
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(returned in both d0 and a0), and floating values in fp0. */
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#undef LIBCALL_VALUE
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#define LIBCALL_VALUE(MODE) \
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(((MODE) == SFmode || (MODE) == DFmode) && TARGET_68881 \
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? gen_rtx (REG, (MODE), 16) \
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: gen_rtx (REG, (MODE), 0))
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/* Boundary (in *bits*) on which stack pointer should be aligned.
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The m68k/SVR4 convention is to keep the stack pointer longword aligned. */
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#undef STACK_BOUNDARY
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#define STACK_BOUNDARY 32
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/* Alignment of field after `int : 0' in a structure.
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For m68k/SVR4, this is the next longword boundary. */
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#undef EMPTY_FIELD_BOUNDARY
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#define EMPTY_FIELD_BOUNDARY 32
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/* No data type wants to be aligned rounder than this.
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For m68k/SVR4, some types (doubles for example) are aligned on 8 byte
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boundaries */
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#undef BIGGEST_ALIGNMENT
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#define BIGGEST_ALIGNMENT 64
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