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160 lines
5.1 KiB
C
160 lines
5.1 KiB
C
/* Assembler macros for i386.
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Copyright (C) 1991-2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sysdeps/generic/sysdep.h>
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#include <features.h> /* For __GNUC_PREREQ. */
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/* It is desirable that the names of PIC thunks match those used by
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GCC so that multiple copies are eliminated by the linker. Because
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GCC 4.6 and earlier use __i686 in the names, it is necessary to
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override that predefined macro. */
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#if defined __i686 && defined __ASSEMBLER__
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#undef __i686
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#define __i686 __i686
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#endif
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#ifdef __ASSEMBLER__
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# define GET_PC_THUNK(reg) __x86.get_pc_thunk.reg
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#else
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# define GET_PC_THUNK_STR(reg) "__x86.get_pc_thunk." #reg
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#endif
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#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
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/* ELF uses byte-counts for .align, most others use log2 of count of bytes. */
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#define ALIGNARG(log2) 1<<log2
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name;
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/* Define an entry point visible from C.
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There is currently a bug in gdb which prevents us from specifying
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incomplete stabs information. Fake some entries here which specify
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the current source file. */
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#define ENTRY(name) \
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.globl C_SYMBOL_NAME(name); \
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.type C_SYMBOL_NAME(name),@function; \
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.align ALIGNARG(4); \
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C_LABEL(name) \
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cfi_startproc; \
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CALL_MCOUNT
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#undef END
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#define END(name) \
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cfi_endproc; \
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ASM_SIZE_DIRECTIVE(name)
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#define ENTRY_CHK(name) ENTRY (name)
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#define END_CHK(name) END (name)
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/* If compiled for profiling, call `mcount' at the start of each function. */
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#ifdef PROF
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/* The mcount code relies on a normal frame pointer being on the stack
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to locate our caller, so push one just for its benefit. */
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#define CALL_MCOUNT \
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pushl %ebp; cfi_adjust_cfa_offset (4); movl %esp, %ebp; \
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cfi_def_cfa_register (ebp); call JUMPTARGET(mcount); \
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popl %ebp; cfi_def_cfa (esp, 4);
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#else
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#define CALL_MCOUNT /* Do nothing. */
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#endif
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/* Since C identifiers are not normally prefixed with an underscore
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on this system, the asm identifier `syscall_error' intrudes on the
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C name space. Make sure we use an innocuous name. */
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#define syscall_error __syscall_error
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#define mcount _mcount
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#define PSEUDO(name, syscall_name, args) \
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.globl syscall_error; \
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lose: SYSCALL_PIC_SETUP \
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jmp JUMPTARGET(syscall_error); \
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ENTRY (name) \
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DO_CALL (syscall_name, args); \
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jb lose
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#undef PSEUDO_END
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#define PSEUDO_END(name) \
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END (name)
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# define SETUP_PIC_REG(reg) \
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.ifndef GET_PC_THUNK(reg); \
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.section .gnu.linkonce.t.GET_PC_THUNK(reg),"ax",@progbits; \
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.globl GET_PC_THUNK(reg); \
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.hidden GET_PC_THUNK(reg); \
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.p2align 4; \
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.type GET_PC_THUNK(reg),@function; \
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GET_PC_THUNK(reg): \
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movl (%esp), %e##reg; \
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ret; \
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.size GET_PC_THUNK(reg), . - GET_PC_THUNK(reg); \
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.previous; \
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.endif; \
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call GET_PC_THUNK(reg)
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# define LOAD_PIC_REG(reg) \
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SETUP_PIC_REG(reg); addl $_GLOBAL_OFFSET_TABLE_, %e##reg
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#undef JUMPTARGET
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#ifdef PIC
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#define JUMPTARGET(name) name##@PLT
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#define SYSCALL_PIC_SETUP \
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pushl %ebx; \
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cfi_adjust_cfa_offset (4); \
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call 0f; \
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0: popl %ebx; \
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cfi_adjust_cfa_offset (-4); \
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addl $_GLOBAL_OFFSET_TABLE_+[.-0b], %ebx;
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#else
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#define JUMPTARGET(name) name
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#define SYSCALL_PIC_SETUP /* Nothing. */
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#endif
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/* Local label name for asm code. */
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#ifndef L
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#define L(name) .L##name
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#endif
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#define atom_text_section .section ".text.atom", "ax"
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#else /* __ASSEMBLER__ */
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# define SETUP_PIC_REG_STR(reg) \
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".ifndef " GET_PC_THUNK_STR (reg) "\n" \
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".section .gnu.linkonce.t." GET_PC_THUNK_STR (reg) ",\"ax\",@progbits\n" \
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".globl " GET_PC_THUNK_STR (reg) "\n" \
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".hidden " GET_PC_THUNK_STR (reg) "\n" \
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".p2align 4\n" \
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".type " GET_PC_THUNK_STR (reg) ",@function\n" \
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GET_PC_THUNK_STR (reg) ":" \
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"movl (%%esp), %%e" #reg "\n" \
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"ret\n" \
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".size " GET_PC_THUNK_STR (reg) ", . - " GET_PC_THUNK_STR (reg) "\n" \
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".previous\n" \
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".endif\n" \
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"call " GET_PC_THUNK_STR (reg)
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# define LOAD_PIC_REG_STR(reg) \
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SETUP_PIC_REG_STR (reg) "\naddl $_GLOBAL_OFFSET_TABLE_, %%e" #reg
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#endif /* __ASSEMBLER__ */
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