diff options
Diffstat (limited to 'contrib/arm-optimized-routines/string/aarch64/strcmp-mte.S')
| -rw-r--r-- | contrib/arm-optimized-routines/string/aarch64/strcmp-mte.S | 189 |
1 files changed, 0 insertions, 189 deletions
diff --git a/contrib/arm-optimized-routines/string/aarch64/strcmp-mte.S b/contrib/arm-optimized-routines/string/aarch64/strcmp-mte.S deleted file mode 100644 index 12d1a6b51dd3..000000000000 --- a/contrib/arm-optimized-routines/string/aarch64/strcmp-mte.S +++ /dev/null @@ -1,189 +0,0 @@ -/* - * strcmp - compare two strings - * - * Copyright (c) 2012-2020, Arm Limited. - * SPDX-License-Identifier: MIT - */ - - -/* Assumptions: - * - * ARMv8-a, AArch64. - * MTE compatible. - */ - -#include "../asmdefs.h" - -#define REP8_01 0x0101010101010101 -#define REP8_7f 0x7f7f7f7f7f7f7f7f - -#define src1 x0 -#define src2 x1 -#define result x0 - -#define data1 x2 -#define data1w w2 -#define data2 x3 -#define data2w w3 -#define has_nul x4 -#define diff x5 -#define off1 x5 -#define syndrome x6 -#define tmp x6 -#define data3 x7 -#define zeroones x8 -#define shift x9 -#define off2 x10 - -/* On big-endian early bytes are at MSB and on little-endian LSB. - LS_FW means shifting towards early bytes. */ -#ifdef __AARCH64EB__ -# define LS_FW lsl -#else -# define LS_FW lsr -#endif - -/* NUL detection works on the principle that (X - 1) & (~X) & 0x80 - (=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and - can be done in parallel across the entire word. - Since carry propagation makes 0x1 bytes before a NUL byte appear - NUL too in big-endian, byte-reverse the data before the NUL check. */ - - -ENTRY (__strcmp_aarch64_mte) - PTR_ARG (0) - PTR_ARG (1) - sub off2, src2, src1 - mov zeroones, REP8_01 - and tmp, src1, 7 - tst off2, 7 - b.ne L(misaligned8) - cbnz tmp, L(mutual_align) - - .p2align 4 - -L(loop_aligned): - ldr data2, [src1, off2] - ldr data1, [src1], 8 -L(start_realigned): -#ifdef __AARCH64EB__ - rev tmp, data1 - sub has_nul, tmp, zeroones - orr tmp, tmp, REP8_7f -#else - sub has_nul, data1, zeroones - orr tmp, data1, REP8_7f -#endif - bics has_nul, has_nul, tmp /* Non-zero if NUL terminator. */ - ccmp data1, data2, 0, eq - b.eq L(loop_aligned) -#ifdef __AARCH64EB__ - rev has_nul, has_nul -#endif - eor diff, data1, data2 - orr syndrome, diff, has_nul -L(end): -#ifndef __AARCH64EB__ - rev syndrome, syndrome - rev data1, data1 - rev data2, data2 -#endif - clz shift, syndrome - /* The most-significant-non-zero bit of the syndrome marks either the - first bit that is different, or the top bit of the first zero byte. - Shifting left now will bring the critical information into the - top bits. */ - lsl data1, data1, shift - lsl data2, data2, shift - /* 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 - - .p2align 4 - -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 - ldr data2, [src1, off2] - ldr data1, [src1], 8 - neg shift, src2, lsl 3 /* Bits to alignment -64. */ - mov tmp, -1 - LS_FW tmp, tmp, shift - orr data1, data1, tmp - orr data2, data2, tmp - b L(start_realigned) - -L(misaligned8): - /* Align SRC1 to 8 bytes and then compare 8 bytes at a time, always - checking to make sure that we don't access beyond the end of SRC2. */ - cbz tmp, L(src1_aligned) -L(do_misaligned): - ldrb data1w, [src1], 1 - ldrb data2w, [src2], 1 - cmp data1w, 0 - ccmp data1w, data2w, 0, ne /* NZCV = 0b0000. */ - b.ne L(done) - tst src1, 7 - b.ne L(do_misaligned) - -L(src1_aligned): - neg shift, src2, lsl 3 - bic src2, src2, 7 - ldr data3, [src2], 8 -#ifdef __AARCH64EB__ - rev data3, data3 -#endif - lsr tmp, zeroones, shift - orr data3, data3, tmp - sub has_nul, data3, zeroones - orr tmp, data3, REP8_7f - bics has_nul, has_nul, tmp - b.ne L(tail) - - sub off1, src2, src1 - - .p2align 4 - -L(loop_unaligned): - ldr data3, [src1, off1] - ldr data2, [src1, off2] -#ifdef __AARCH64EB__ - rev data3, data3 -#endif - sub has_nul, data3, zeroones - orr tmp, data3, REP8_7f - ldr data1, [src1], 8 - bics has_nul, has_nul, tmp - ccmp data1, data2, 0, eq - b.eq L(loop_unaligned) - - lsl tmp, has_nul, shift -#ifdef __AARCH64EB__ - rev tmp, tmp -#endif - eor diff, data1, data2 - orr syndrome, diff, tmp - cbnz syndrome, L(end) -L(tail): - ldr data1, [src1] - neg shift, shift - lsr data2, data3, shift - lsr has_nul, has_nul, shift -#ifdef __AARCH64EB__ - rev data2, data2 - rev has_nul, has_nul -#endif - eor diff, data1, data2 - orr syndrome, diff, has_nul - b L(end) - -L(done): - sub result, data1, data2 - ret - -END (__strcmp_aarch64_mte) - |