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Diffstat (limited to 'sysdeps/aarch64/memcmp.S')
| -rw-r--r-- | sysdeps/aarch64/memcmp.S | 154 |
1 files changed, 0 insertions, 154 deletions
diff --git a/sysdeps/aarch64/memcmp.S b/sysdeps/aarch64/memcmp.S deleted file mode 100644 index 4cfcb89297..0000000000 --- a/sysdeps/aarch64/memcmp.S +++ /dev/null @@ -1,154 +0,0 @@ -/* memcmp - compare memory - - Copyright (C) 2013-2017 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 - <http://www.gnu.org/licenses/>. */ - -#include <sysdep.h> - -/* Assumptions: - * - * ARMv8-a, AArch64 - */ - -/* Parameters and result. */ -#define src1 x0 -#define src2 x1 -#define limit x2 -#define result x0 - -/* Internal variables. */ -#define data1 x3 -#define data1w w3 -#define data2 x4 -#define data2w w4 -#define has_nul x5 -#define diff x6 -#define endloop x7 -#define tmp1 x8 -#define tmp2 x9 -#define tmp3 x10 -#define pos x11 -#define limit_wd x12 -#define mask x13 - -ENTRY_ALIGN (memcmp, 6) - DELOUSE (0) - DELOUSE (1) - DELOUSE (2) - cbz limit, L(ret0) - eor tmp1, src1, src2 - tst tmp1, #7 - b.ne L(misaligned8) - ands tmp1, src1, #7 - b.ne L(mutual_align) - add limit_wd, limit, #7 - lsr limit_wd, limit_wd, #3 - /* Start of performance-critical section -- one 64B cache line. */ -L(loop_aligned): - ldr data1, [src1], #8 - ldr data2, [src2], #8 -L(start_realigned): - subs limit_wd, limit_wd, #1 - eor diff, data1, data2 /* Non-zero if differences found. */ - csinv endloop, diff, xzr, ne /* Last Dword or differences. */ - cbz endloop, L(loop_aligned) - /* End of performance-critical section -- one 64B cache line. */ - - /* Not reached the limit, must have found a diff. */ - cbnz limit_wd, L(not_limit) - - /* Limit % 8 == 0 => all bytes significant. */ - ands limit, limit, #7 - b.eq L(not_limit) - - lsl limit, limit, #3 /* Bits -> bytes. */ - mov mask, #~0 -#ifdef __AARCH64EB__ - lsr mask, mask, limit -#else - lsl mask, mask, limit -#endif - bic data1, data1, mask - bic data2, data2, mask - - orr diff, diff, mask -L(not_limit): - -#ifndef __AARCH64EB__ - rev diff, diff - rev data1, data1 - rev data2, data2 -#endif - /* The MS-non-zero bit of DIFF marks either the first bit - that is different, or the end of the significant data. - Shifting left now will bring the critical information into the - top bits. */ - clz pos, diff - lsl data1, data1, pos - lsl data2, data2, pos - /* But we need to zero-extend (char is unsigned) the value and then - perform a signed 32-bit subtraction. */ - lsr data1, data1, #56 - sub result, data1, data2, lsr #56 - RET - -L(mutual_align): - /* Sources are mutually aligned, but are not currently at an - alignment boundary. Round down the addresses and then mask off - the bytes that precede the start point. */ - bic src1, src1, #7 - bic src2, src2, #7 - add limit, limit, tmp1 /* Adjust the limit for the extra. */ - lsl tmp1, tmp1, #3 /* Bytes beyond alignment -> bits. */ - ldr data1, [src1], #8 - neg tmp1, tmp1 /* Bits to alignment -64. */ - ldr data2, [src2], #8 - mov tmp2, #~0 -#ifdef __AARCH64EB__ - /* Big-endian. Early bytes are at MSB. */ - lsl tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */ -#else - /* Little-endian. Early bytes are at LSB. */ - lsr tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */ -#endif - add limit_wd, limit, #7 - orr data1, data1, tmp2 - orr data2, data2, tmp2 - lsr limit_wd, limit_wd, #3 - b L(start_realigned) - -L(ret0): - mov result, #0 - RET - - .p2align 6 -L(misaligned8): - sub limit, limit, #1 -1: - /* Perhaps we can do better than this. */ - ldrb data1w, [src1], #1 - ldrb data2w, [src2], #1 - subs limit, limit, #1 - ccmp data1w, data2w, #0, cs /* NZCV = 0b0000. */ - b.eq 1b - sub result, data1, data2 - RET -END (memcmp) -#undef bcmp -weak_alias (memcmp, bcmp) -libc_hidden_builtin_def (memcmp) |