glibc/ports/sysdeps/arm/sysdep.h

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/* Assembler macros for ARM.
Copyright (C) 1997-2013 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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
License as published by the Free Software Foundation; either
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,
but WITHOUT ANY WARRANTY; without even the implied warranty of
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
<http://www.gnu.org/licenses/>. */
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#include <sysdeps/generic/sysdep.h>
#include <features.h>
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/* The __ARM_ARCH define is provided by gcc 4.8. Construct it otherwise. */
#ifndef __ARM_ARCH
# ifdef __ARM_ARCH_2__
# define __ARM_ARCH 2
# elif defined (__ARM_ARCH_3__) || defined (__ARM_ARCH_3M__)
# define __ARM_ARCH 3
# elif defined (__ARM_ARCH_4__) || defined (__ARM_ARCH_4T__)
# define __ARM_ARCH 4
# elif defined (__ARM_ARCH_5__) || defined (__ARM_ARCH_5E__) \
|| defined(__ARM_ARCH_5T__) || defined(__ARM_ARCH_5TE__) \
|| defined(__ARM_ARCH_5TEJ__)
# define __ARM_ARCH 5
# elif defined (__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
|| defined (__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) \
|| defined (__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__)
# define __ARM_ARCH 6
# elif defined (__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
|| defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
|| defined(__ARM_ARCH_7EM__)
# define __ARM_ARCH 7
# else
# error unknown arm architecture
# endif
#endif
#if __ARM_ARCH > 4 || defined (__ARM_ARCH_4T__)
# define ARCH_HAS_BX
#endif
#if __ARM_ARCH > 4
# define ARCH_HAS_BLX
#endif
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#if __ARM_ARCH > 6 || defined (__ARM_ARCH_6K__) || defined (__ARM_ARCH_6ZK__)
# define ARCH_HAS_HARD_TP
#endif
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#if __ARM_ARCH > 6 || defined (__ARM_ARCH_6T2__)
# define ARCH_HAS_T2
#endif
#ifdef __ASSEMBLER__
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/* Syntactic details of assembler. */
#define ALIGNARG(log2) log2
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#define ASM_SIZE_DIRECTIVE(name) .size name,.-name
#define PLTJMP(_x) _x##(PLT)
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#ifdef ARCH_HAS_BX
# define BX(R) bx R
# define BXC(C, R) bx##C R
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# ifdef ARCH_HAS_BLX
# define BLX(R) blx R
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# else
# define BLX(R) mov lr, pc; bx R
# endif
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#else
# define BX(R) mov pc, R
# define BXC(C, R) mov##C pc, R
# define BLX(R) mov lr, pc; mov pc, R
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#endif
#define DO_RET(R) BX(R)
#define RETINSTR(C, R) BXC(C, R)
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/* Define an entry point visible from C. */
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#define ENTRY(name) \
.globl C_SYMBOL_NAME(name); \
.type C_SYMBOL_NAME(name),%function; \
.align ALIGNARG(4); \
C_LABEL(name) \
CFI_SECTIONS; \
cfi_startproc; \
CALL_MCOUNT
#define CFI_SECTIONS \
.cfi_sections .debug_frame
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#undef END
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#define END(name) \
cfi_endproc; \
ASM_SIZE_DIRECTIVE(name)
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/* If compiled for profiling, call `mcount' at the start of each function. */
#ifdef PROF
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/* Call __gnu_mcount_nc if GCC >= 4.4. */
#if __GNUC_PREREQ(4,4)
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#define CALL_MCOUNT \
push {lr}; \
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cfi_adjust_cfa_offset (4); \
cfi_rel_offset (lr, 0); \
bl PLTJMP(mcount); \
cfi_adjust_cfa_offset (-4); \
cfi_restore (lr)
#else /* else call _mcount */
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#define CALL_MCOUNT \
push {lr}; \
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cfi_adjust_cfa_offset (4); \
cfi_rel_offset (lr, 0); \
bl PLTJMP(mcount); \
pops {lr}; \
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cfi_adjust_cfa_offset (-4); \
cfi_restore (lr)
#endif
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#else
#define CALL_MCOUNT /* Do nothing. */
#endif
/* Since C identifiers are not normally prefixed with an underscore
on this system, the asm identifier `syscall_error' intrudes on the
C name space. Make sure we use an innocuous name. */
#define syscall_error __syscall_error
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#if __GNUC_PREREQ(4,4)
#define mcount __gnu_mcount_nc
#else
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#define mcount _mcount
#endif
/* Tag_ABI_align8_preserved: This code preserves 8-byte
alignment in any callee. */
.eabi_attribute 25, 1
/* Tag_ABI_align8_needed: This code may require 8-byte alignment from
the caller. */
.eabi_attribute 24, 1
/* The thumb2 encoding is reasonably complete. Unless suppressed, use it. */
.syntax unified
# if defined(__thumb2__) && !defined(NO_THUMB)
.thumb
#else
# undef __thumb__
# undef __thumb2__
.arm
# endif
/* Load or store to/from a pc-relative EXPR into/from R, using T. */
# ifdef __thumb2__
# define LDST_PCREL(OP, R, T, EXPR) \
ldr T, 98f; \
.subsection 2; \
98: .word EXPR - 99f - PC_OFS; \
.previous; \
99: add T, T, pc; \
OP R, [T]
# else
# define LDST_PCREL(OP, R, T, EXPR) \
ldr T, 98f; \
.subsection 2; \
98: .word EXPR - 99f - PC_OFS; \
.previous; \
99: OP R, [pc, T]
# endif
/* Cope with negative memory offsets, which thumb can't encode.
Use NEGOFF_ADJ_BASE to (conditionally) alter the base register,
and then NEGOFF_OFF1 to use 0 for thumb and the offset for arm,
or NEGOFF_OFF2 to use A-B for thumb and A for arm. */
# ifdef __thumb2__
# define NEGOFF_ADJ_BASE(R, OFF) add R, R, $OFF
# define NEGOFF_ADJ_BASE2(D, S, OFF) add D, S, $OFF
# define NEGOFF_OFF1(R, OFF) [R]
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $((OFFA) - (OFFB))]
# else
# define NEGOFF_ADJ_BASE(R, OFF)
# define NEGOFF_ADJ_BASE2(D, S, OFF) mov D, S
# define NEGOFF_OFF1(R, OFF) [R, $OFF]
# define NEGOFF_OFF2(R, OFFA, OFFB) [R, $OFFA]
# endif
/* Helper to get the TLS base pointer. The interface is that TMP is a
register that may be used to hold the LR, if necessary. TMP may be
LR itself to indicate that LR need not be saved. The base pointer
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is returned in R0. Only R0 and TMP are modified. */
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# ifdef ARCH_HAS_HARD_TP
/* If the cpu has cp15 available, use it. */
# define GET_TLS(TMP) mrc p15, 0, r0, c13, c0, 3
# else
/* At this generic level we have no tricks to pull. Call the ABI routine. */
# define GET_TLS(TMP) \
push { r1, r2, r3, lr }; \
cfi_remember_state; \
cfi_adjust_cfa_offset (16); \
cfi_rel_offset (r1, 0); \
cfi_rel_offset (r2, 4); \
cfi_rel_offset (r3, 8); \
cfi_rel_offset (lr, 12); \
bl __aeabi_read_tp; \
pop { r1, r2, r3, lr }; \
cfi_restore_state
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# endif /* ARCH_HAS_HARD_TP */
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# ifndef ARM_SFI_MACROS
# define ARM_SFI_MACROS 1
/* This assembly macro is prepended to any load/store instruction,
pulling the base register out of the addressing mode syntax and
making it the first operand of the macro. For example:
ldr r0, [r1]
becomes:
sfi_breg r1, ldr r0, [\B]
The \B stands in for the base register that is the first operand
to the macro, so we can avoid error-prone repetition of the base
register in two places on the line.
This is used for all memory access through a base register other
than PC or SP. It's intended to support SFI schemes such as
Native Client, where the OS will enforce that all load/store
instructions use a special form. In any such configuration,
another sysdep.h file will have defined ARM_SFI_MACROS and
provided its own assembly macros with the same interface. */
.macro sfi_breg basereg, insn, operands:vararg
.macro _sfi_breg_doit B
\insn \operands
.endm
_sfi_breg_doit \basereg
.purgem _sfi_breg_doit
.endm
/* This assembly macro replaces the "pld" instruction.
The syntax:
sfi_pld REGISTER, #OFFSET
is exactly equivalent to:
sfi_breg REGISTER, pld [\B, #OFFSET]
(and ", #OFFSET" is optional). We have a separate macro
only to work around a bug in GAS versions prior to 2.23.2,
that misparses the sfi_breg macro expansion in this case. */
.macro sfi_pld basereg, offset=#0
pld [\basereg, \offset]
.endm
# endif
#endif /* __ASSEMBLER__ */
/* This number is the offset from the pc at the current location. */
#ifdef __thumb__
# define PC_OFS 4
#else
# define PC_OFS 8
#endif