glibc/sysdeps/i386/memcopy.h

89 lines
3.3 KiB
C

/* memcopy.h -- definitions for memory copy functions. i386 version.
Copyright (C) 1991-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdeps/generic/memcopy.h>
#undef BYTE_COPY_FWD
#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \
do { \
int __d0; \
asm volatile(/* Clear the direction flag, so copying goes forward. */ \
"cld\n" \
/* Copy bytes. */ \
"rep\n" \
"movsb" : \
"=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \
"0" (dst_bp), "1" (src_bp), "2" (nbytes) : \
"memory"); \
} while (0)
#undef BYTE_COPY_BWD
#define BYTE_COPY_BWD(dst_ep, src_ep, nbytes) \
do \
{ \
int __d0; \
asm volatile(/* Set the direction flag, so copying goes backwards. */ \
"std\n" \
/* Copy bytes. */ \
"rep\n" \
"movsb\n" \
/* Clear the dir flag. Convention says it should be 0. */ \
"cld" : \
"=D" (dst_ep), "=S" (src_ep), "=c" (__d0) : \
"0" (dst_ep - 1), "1" (src_ep - 1), "2" (nbytes) : \
"memory"); \
dst_ep += 1; \
src_ep += 1; \
} while (0)
#undef WORD_COPY_FWD
#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes) \
do \
{ \
int __d0; \
asm volatile(/* Clear the direction flag, so copying goes forward. */ \
"cld\n" \
/* Copy longwords. */ \
"rep\n" \
"movsl" : \
"=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \
"0" (dst_bp), "1" (src_bp), "2" ((nbytes) / 4) : \
"memory"); \
(nbytes_left) = (nbytes) % 4; \
} while (0)
#undef WORD_COPY_BWD
#define WORD_COPY_BWD(dst_ep, src_ep, nbytes_left, nbytes) \
do \
{ \
int __d0; \
asm volatile(/* Set the direction flag, so copying goes backwards. */ \
"std\n" \
/* Copy longwords. */ \
"rep\n" \
"movsl\n" \
/* Clear the dir flag. Convention says it should be 0. */ \
"cld" : \
"=D" (dst_ep), "=S" (src_ep), "=c" (__d0) : \
"0" (dst_ep - 4), "1" (src_ep - 4), "2" ((nbytes) / 4) : \
"memory"); \
dst_ep += 4; \
src_ep += 4; \
(nbytes_left) = (nbytes) % 4; \
} while (0)