[PATCH v1] x86: Move strcpy SSE2 implementation to multiarch/strcpy-sse2.S
H.J. Lu
hjl.tools@gmail.com
Tue Jul 12 23:23:35 GMT 2022
On Tue, Jul 12, 2022 at 12:29 PM Noah Goldstein <goldstein.w.n@gmail.com> wrote:
>
> This commit doesn't affect libc.so.6, its just housekeeping to prepare
> for adding explicit ISA level support.
>
> Tested build on x86_64 and x86_32 with/without multiarch.
> ---
> sysdeps/x86_64/multiarch/rtld-stpcpy.S | 18 ++++
> sysdeps/x86_64/multiarch/stpcpy-sse2.S | 15 +--
> sysdeps/x86_64/multiarch/strcpy-sse2.S | 137 ++++++++++++++++++++++--
> sysdeps/x86_64/stpcpy.S | 3 +-
> sysdeps/x86_64/strcpy.S | 138 +------------------------
> 5 files changed, 156 insertions(+), 155 deletions(-)
> create mode 100644 sysdeps/x86_64/multiarch/rtld-stpcpy.S
>
> diff --git a/sysdeps/x86_64/multiarch/rtld-stpcpy.S b/sysdeps/x86_64/multiarch/rtld-stpcpy.S
> new file mode 100644
> index 0000000000..914141f07f
> --- /dev/null
> +++ b/sysdeps/x86_64/multiarch/rtld-stpcpy.S
> @@ -0,0 +1,18 @@
> +/* Copyright (C) 2022 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 "../stpcpy.S"
> diff --git a/sysdeps/x86_64/multiarch/stpcpy-sse2.S b/sysdeps/x86_64/multiarch/stpcpy-sse2.S
> index 078504a44e..ea9f973af3 100644
> --- a/sysdeps/x86_64/multiarch/stpcpy-sse2.S
> +++ b/sysdeps/x86_64/multiarch/stpcpy-sse2.S
> @@ -17,17 +17,10 @@
> <https://www.gnu.org/licenses/>. */
>
> #if IS_IN (libc)
> -
> -# include <sysdep.h>
> -# define __stpcpy __stpcpy_sse2
> -
> -# undef weak_alias
> -# define weak_alias(ignored1, ignored2)
> -# undef libc_hidden_def
> -# define libc_hidden_def(__stpcpy)
> -# undef libc_hidden_builtin_def
> -# define libc_hidden_builtin_def(stpcpy)
> +# ifndef STRCPY
> +# define STRCPY __stpcpy_sse2
> +# endif
> #endif
>
> #define USE_AS_STPCPY
> -#include <sysdeps/x86_64/stpcpy.S>
> +#include "strcpy-sse2.S"
> diff --git a/sysdeps/x86_64/multiarch/strcpy-sse2.S b/sysdeps/x86_64/multiarch/strcpy-sse2.S
> index f37967c441..8b5db8b13d 100644
> --- a/sysdeps/x86_64/multiarch/strcpy-sse2.S
> +++ b/sysdeps/x86_64/multiarch/strcpy-sse2.S
> @@ -17,12 +17,137 @@
> <https://www.gnu.org/licenses/>. */
>
> #if IS_IN (libc)
> +# ifndef STRCPY
> +# define STRCPY __strcpy_sse2
> +# endif
> +#endif
>
> -# include <sysdep.h>
> -# define strcpy __strcpy_sse2
> +#include <sysdep.h>
>
> -# undef libc_hidden_builtin_def
> -# define libc_hidden_builtin_def(strcpy)
> -#endif
> + .text
> +ENTRY (STRCPY)
> + movq %rsi, %rcx /* Source register. */
> + andl $7, %ecx /* mask alignment bits */
> + movq %rdi, %rdx /* Duplicate destination pointer. */
> +
> + jz 5f /* aligned => start loop */
> +
> + neg %ecx /* We need to align to 8 bytes. */
> + addl $8,%ecx
> + /* Search the first bytes directly. */
> +0:
> + movb (%rsi), %al /* Fetch a byte */
> + testb %al, %al /* Is it NUL? */
> + movb %al, (%rdx) /* Store it */
> + jz 4f /* If it was NUL, done! */
> + incq %rsi
> + incq %rdx
> + decl %ecx
> + jnz 0b
> +
> +5:
> + movq $0xfefefefefefefeff,%r8
> +
> + /* Now the sources is aligned. Unfortunatly we cannot force
> + to have both source and destination aligned, so ignore the
> + alignment of the destination. */
> + .p2align 4
> +1:
> + /* 1st unroll. */
> + movq (%rsi), %rax /* Read double word (8 bytes). */
> + addq $8, %rsi /* Adjust pointer for next word. */
> + movq %rax, %r9 /* Save a copy for NUL finding. */
> + addq %r8, %r9 /* add the magic value to the word. We get
> + carry bits reported for each byte which
> + is *not* 0 */
> + jnc 3f /* highest byte is NUL => return pointer */
> + xorq %rax, %r9 /* (word+magic)^word */
> + orq %r8, %r9 /* set all non-carry bits */
> + incq %r9 /* add 1: if one carry bit was *not* set
> + the addition will not result in 0. */
> +
> + jnz 3f /* found NUL => return pointer */
> +
> + movq %rax, (%rdx) /* Write value to destination. */
> + addq $8, %rdx /* Adjust pointer. */
> +
> + /* 2nd unroll. */
> + movq (%rsi), %rax /* Read double word (8 bytes). */
> + addq $8, %rsi /* Adjust pointer for next word. */
> + movq %rax, %r9 /* Save a copy for NUL finding. */
> + addq %r8, %r9 /* add the magic value to the word. We get
> + carry bits reported for each byte which
> + is *not* 0 */
> + jnc 3f /* highest byte is NUL => return pointer */
> + xorq %rax, %r9 /* (word+magic)^word */
> + orq %r8, %r9 /* set all non-carry bits */
> + incq %r9 /* add 1: if one carry bit was *not* set
> + the addition will not result in 0. */
> +
> + jnz 3f /* found NUL => return pointer */
>
> -#include <sysdeps/x86_64/strcpy.S>
> + movq %rax, (%rdx) /* Write value to destination. */
> + addq $8, %rdx /* Adjust pointer. */
> +
> + /* 3rd unroll. */
> + movq (%rsi), %rax /* Read double word (8 bytes). */
> + addq $8, %rsi /* Adjust pointer for next word. */
> + movq %rax, %r9 /* Save a copy for NUL finding. */
> + addq %r8, %r9 /* add the magic value to the word. We get
> + carry bits reported for each byte which
> + is *not* 0 */
> + jnc 3f /* highest byte is NUL => return pointer */
> + xorq %rax, %r9 /* (word+magic)^word */
> + orq %r8, %r9 /* set all non-carry bits */
> + incq %r9 /* add 1: if one carry bit was *not* set
> + the addition will not result in 0. */
> +
> + jnz 3f /* found NUL => return pointer */
> +
> + movq %rax, (%rdx) /* Write value to destination. */
> + addq $8, %rdx /* Adjust pointer. */
> +
> + /* 4th unroll. */
> + movq (%rsi), %rax /* Read double word (8 bytes). */
> + addq $8, %rsi /* Adjust pointer for next word. */
> + movq %rax, %r9 /* Save a copy for NUL finding. */
> + addq %r8, %r9 /* add the magic value to the word. We get
> + carry bits reported for each byte which
> + is *not* 0 */
> + jnc 3f /* highest byte is NUL => return pointer */
> + xorq %rax, %r9 /* (word+magic)^word */
> + orq %r8, %r9 /* set all non-carry bits */
> + incq %r9 /* add 1: if one carry bit was *not* set
> + the addition will not result in 0. */
> +
> + jnz 3f /* found NUL => return pointer */
> +
> + movq %rax, (%rdx) /* Write value to destination. */
> + addq $8, %rdx /* Adjust pointer. */
> + jmp 1b /* Next iteration. */
> +
> + /* Do the last few bytes. %rax contains the value to write.
> + The loop is unrolled twice. */
> + .p2align 4
> +3:
> + /* Note that stpcpy needs to return with the value of the NUL
> + byte. */
> + movb %al, (%rdx) /* 1st byte. */
> + testb %al, %al /* Is it NUL. */
> + jz 4f /* yes, finish. */
> + incq %rdx /* Increment destination. */
> + movb %ah, (%rdx) /* 2nd byte. */
> + testb %ah, %ah /* Is it NUL?. */
> + jz 4f /* yes, finish. */
> + incq %rdx /* Increment destination. */
> + shrq $16, %rax /* Shift... */
> + jmp 3b /* and look at next two bytes in %rax. */
> +
> +4:
> +#ifdef USE_AS_STPCPY
> + movq %rdx, %rax /* Destination is return value. */
> +#else
> + movq %rdi, %rax /* Source is return value. */
> +#endif
> + retq
> +END (STRCPY)
> diff --git a/sysdeps/x86_64/stpcpy.S b/sysdeps/x86_64/stpcpy.S
> index ec23de1416..b097c203dd 100644
> --- a/sysdeps/x86_64/stpcpy.S
> +++ b/sysdeps/x86_64/stpcpy.S
> @@ -1,7 +1,6 @@
> -#define USE_AS_STPCPY
> #define STRCPY __stpcpy
>
> -#include <sysdeps/x86_64/strcpy.S>
> +#include "multiarch/stpcpy-sse2.S"
>
> weak_alias (__stpcpy, stpcpy)
> libc_hidden_def (__stpcpy)
> diff --git a/sysdeps/x86_64/strcpy.S b/sysdeps/x86_64/strcpy.S
> index 17e8073550..05f19e6e94 100644
> --- a/sysdeps/x86_64/strcpy.S
> +++ b/sysdeps/x86_64/strcpy.S
> @@ -16,140 +16,6 @@
> License along with the GNU C Library; if not, see
> <https://www.gnu.org/licenses/>. */
>
> -#include <sysdep.h>
> -#include "asm-syntax.h"
> -
> -#ifndef USE_AS_STPCPY
> -# define STRCPY strcpy
> -#endif
> -
> - .text
> -ENTRY (STRCPY)
> - movq %rsi, %rcx /* Source register. */
> - andl $7, %ecx /* mask alignment bits */
> - movq %rdi, %rdx /* Duplicate destination pointer. */
> -
> - jz 5f /* aligned => start loop */
> -
> - neg %ecx /* We need to align to 8 bytes. */
> - addl $8,%ecx
> - /* Search the first bytes directly. */
> -0:
> - movb (%rsi), %al /* Fetch a byte */
> - testb %al, %al /* Is it NUL? */
> - movb %al, (%rdx) /* Store it */
> - jz 4f /* If it was NUL, done! */
> - incq %rsi
> - incq %rdx
> - decl %ecx
> - jnz 0b
> -
> -5:
> - movq $0xfefefefefefefeff,%r8
> -
> - /* Now the sources is aligned. Unfortunatly we cannot force
> - to have both source and destination aligned, so ignore the
> - alignment of the destination. */
> - .p2align 4
> -1:
> - /* 1st unroll. */
> - movq (%rsi), %rax /* Read double word (8 bytes). */
> - addq $8, %rsi /* Adjust pointer for next word. */
> - movq %rax, %r9 /* Save a copy for NUL finding. */
> - addq %r8, %r9 /* add the magic value to the word. We get
> - carry bits reported for each byte which
> - is *not* 0 */
> - jnc 3f /* highest byte is NUL => return pointer */
> - xorq %rax, %r9 /* (word+magic)^word */
> - orq %r8, %r9 /* set all non-carry bits */
> - incq %r9 /* add 1: if one carry bit was *not* set
> - the addition will not result in 0. */
> -
> - jnz 3f /* found NUL => return pointer */
> -
> - movq %rax, (%rdx) /* Write value to destination. */
> - addq $8, %rdx /* Adjust pointer. */
> -
> - /* 2nd unroll. */
> - movq (%rsi), %rax /* Read double word (8 bytes). */
> - addq $8, %rsi /* Adjust pointer for next word. */
> - movq %rax, %r9 /* Save a copy for NUL finding. */
> - addq %r8, %r9 /* add the magic value to the word. We get
> - carry bits reported for each byte which
> - is *not* 0 */
> - jnc 3f /* highest byte is NUL => return pointer */
> - xorq %rax, %r9 /* (word+magic)^word */
> - orq %r8, %r9 /* set all non-carry bits */
> - incq %r9 /* add 1: if one carry bit was *not* set
> - the addition will not result in 0. */
> -
> - jnz 3f /* found NUL => return pointer */
> -
> - movq %rax, (%rdx) /* Write value to destination. */
> - addq $8, %rdx /* Adjust pointer. */
> -
> - /* 3rd unroll. */
> - movq (%rsi), %rax /* Read double word (8 bytes). */
> - addq $8, %rsi /* Adjust pointer for next word. */
> - movq %rax, %r9 /* Save a copy for NUL finding. */
> - addq %r8, %r9 /* add the magic value to the word. We get
> - carry bits reported for each byte which
> - is *not* 0 */
> - jnc 3f /* highest byte is NUL => return pointer */
> - xorq %rax, %r9 /* (word+magic)^word */
> - orq %r8, %r9 /* set all non-carry bits */
> - incq %r9 /* add 1: if one carry bit was *not* set
> - the addition will not result in 0. */
> -
> - jnz 3f /* found NUL => return pointer */
> -
> - movq %rax, (%rdx) /* Write value to destination. */
> - addq $8, %rdx /* Adjust pointer. */
> -
> - /* 4th unroll. */
> - movq (%rsi), %rax /* Read double word (8 bytes). */
> - addq $8, %rsi /* Adjust pointer for next word. */
> - movq %rax, %r9 /* Save a copy for NUL finding. */
> - addq %r8, %r9 /* add the magic value to the word. We get
> - carry bits reported for each byte which
> - is *not* 0 */
> - jnc 3f /* highest byte is NUL => return pointer */
> - xorq %rax, %r9 /* (word+magic)^word */
> - orq %r8, %r9 /* set all non-carry bits */
> - incq %r9 /* add 1: if one carry bit was *not* set
> - the addition will not result in 0. */
> -
> - jnz 3f /* found NUL => return pointer */
> -
> - movq %rax, (%rdx) /* Write value to destination. */
> - addq $8, %rdx /* Adjust pointer. */
> - jmp 1b /* Next iteration. */
> -
> - /* Do the last few bytes. %rax contains the value to write.
> - The loop is unrolled twice. */
> - .p2align 4
> -3:
> - /* Note that stpcpy needs to return with the value of the NUL
> - byte. */
> - movb %al, (%rdx) /* 1st byte. */
> - testb %al, %al /* Is it NUL. */
> - jz 4f /* yes, finish. */
> - incq %rdx /* Increment destination. */
> - movb %ah, (%rdx) /* 2nd byte. */
> - testb %ah, %ah /* Is it NUL?. */
> - jz 4f /* yes, finish. */
> - incq %rdx /* Increment destination. */
> - shrq $16, %rax /* Shift... */
> - jmp 3b /* and look at next two bytes in %rax. */
> -
> -4:
> -#ifdef USE_AS_STPCPY
> - movq %rdx, %rax /* Destination is return value. */
> -#else
> - movq %rdi, %rax /* Source is return value. */
> -#endif
> - retq
> -END (STRCPY)
> -#ifndef USE_AS_STPCPY
> +#define STRCPY strcpy
> +#include "multiarch/strcpy-sse2.S"
> libc_hidden_builtin_def (strcpy)
> -#endif
> --
> 2.34.1
>
LGTM.
Thanks.
--
H.J.
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