diff options
Diffstat (limited to 'contrib/arm-optimized-routines/string/aarch64/memcmp.S')
| -rw-r--r-- | contrib/arm-optimized-routines/string/aarch64/memcmp.S | 239 |
1 files changed, 146 insertions, 93 deletions
diff --git a/contrib/arm-optimized-routines/string/aarch64/memcmp.S b/contrib/arm-optimized-routines/string/aarch64/memcmp.S index 3b1026642eee..35135e72cc8e 100644 --- a/contrib/arm-optimized-routines/string/aarch64/memcmp.S +++ b/contrib/arm-optimized-routines/string/aarch64/memcmp.S @@ -1,103 +1,84 @@ /* memcmp - compare memory * - * Copyright (c) 2013-2020, Arm Limited. - * SPDX-License-Identifier: MIT + * Copyright (c) 2013-2022, Arm Limited. + * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception */ /* Assumptions: * - * ARMv8-a, AArch64, unaligned accesses. + * ARMv8-a, AArch64, Advanced SIMD, unaligned accesses. */ -#include "../asmdefs.h" +#include "asmdefs.h" -/* Parameters and result. */ -#define src1 x0 -#define src2 x1 -#define limit x2 -#define result w0 +#define src1 x0 +#define src2 x1 +#define limit x2 +#define result w0 + +#define data1 x3 +#define data1w w3 +#define data2 x4 +#define data2w w4 +#define data3 x5 +#define data3w w5 +#define data4 x6 +#define data4w w6 +#define tmp x6 +#define src1end x7 +#define src2end x8 -/* Internal variables. */ -#define data1 x3 -#define data1w w3 -#define data1h x4 -#define data2 x5 -#define data2w w5 -#define data2h x6 -#define tmp1 x7 -#define tmp2 x8 ENTRY (__memcmp_aarch64) PTR_ARG (0) PTR_ARG (1) SIZE_ARG (2) - subs limit, limit, 8 - b.lo L(less8) - - ldr data1, [src1], 8 - ldr data2, [src2], 8 - cmp data1, data2 - b.ne L(return) - - subs limit, limit, 8 - b.gt L(more16) - ldr data1, [src1, limit] - ldr data2, [src2, limit] - b L(return) - -L(more16): - ldr data1, [src1], 8 - ldr data2, [src2], 8 - cmp data1, data2 - bne L(return) - - /* Jump directly to comparing the last 16 bytes for 32 byte (or less) - strings. */ - subs limit, limit, 16 + cmp limit, 16 + b.lo L(less16) + ldp data1, data3, [src1] + ldp data2, data4, [src2] + ccmp data1, data2, 0, ne + ccmp data3, data4, 0, eq + b.ne L(return2) + + add src1end, src1, limit + add src2end, src2, limit + cmp limit, 32 b.ls L(last_bytes) + cmp limit, 160 + b.hs L(loop_align) + sub limit, limit, 32 - /* We overlap loads between 0-32 bytes at either side of SRC1 when we - try to align, so limit it only to strings larger than 128 bytes. */ - cmp limit, 96 - b.ls L(loop16) - - /* Align src1 and adjust src2 with bytes not yet done. */ - and tmp1, src1, 15 - add limit, limit, tmp1 - sub src1, src1, tmp1 - sub src2, src2, tmp1 - - /* Loop performing 16 bytes per iteration using aligned src1. - Limit is pre-decremented by 16 and must be larger than zero. - Exit if <= 16 bytes left to do or if the data is not equal. */ .p2align 4 -L(loop16): - ldp data1, data1h, [src1], 16 - ldp data2, data2h, [src2], 16 - subs limit, limit, 16 - ccmp data1, data2, 0, hi - ccmp data1h, data2h, 0, eq - b.eq L(loop16) - +L(loop32): + ldp data1, data3, [src1, 16] + ldp data2, data4, [src2, 16] cmp data1, data2 - bne L(return) - mov data1, data1h - mov data2, data2h + ccmp data3, data4, 0, eq + b.ne L(return2) + cmp limit, 16 + b.ls L(last_bytes) + + ldp data1, data3, [src1, 32] + ldp data2, data4, [src2, 32] cmp data1, data2 - bne L(return) + ccmp data3, data4, 0, eq + b.ne L(return2) + add src1, src1, 32 + add src2, src2, 32 +L(last64): + subs limit, limit, 32 + b.hi L(loop32) /* Compare last 1-16 bytes using unaligned access. */ L(last_bytes): - add src1, src1, limit - add src2, src2, limit - ldp data1, data1h, [src1] - ldp data2, data2h, [src2] - cmp data1, data2 - bne L(return) - mov data1, data1h - mov data2, data2h + ldp data1, data3, [src1end, -16] + ldp data2, data4, [src2end, -16] +L(return2): cmp data1, data2 + csel data1, data1, data3, ne + csel data2, data2, data4, ne /* Compare data bytes and set return value to 0, -1 or 1. */ L(return): @@ -105,33 +86,105 @@ L(return): rev data1, data1 rev data2, data2 #endif - cmp data1, data2 -L(ret_eq): + cmp data1, data2 cset result, ne cneg result, result, lo ret .p2align 4 - /* Compare up to 8 bytes. Limit is [-8..-1]. */ +L(less16): + add src1end, src1, limit + add src2end, src2, limit + tbz limit, 3, L(less8) + ldr data1, [src1] + ldr data2, [src2] + ldr data3, [src1end, -8] + ldr data4, [src2end, -8] + b L(return2) + + .p2align 4 L(less8): - adds limit, limit, 4 - b.lo L(less4) - ldr data1w, [src1], 4 - ldr data2w, [src2], 4 + tbz limit, 2, L(less4) + ldr data1w, [src1] + ldr data2w, [src2] + ldr data3w, [src1end, -4] + ldr data4w, [src2end, -4] + b L(return2) + +L(less4): + tbz limit, 1, L(less2) + ldrh data1w, [src1] + ldrh data2w, [src2] cmp data1w, data2w b.ne L(return) - sub limit, limit, 4 -L(less4): - adds limit, limit, 4 - beq L(ret_eq) -L(byte_loop): - ldrb data1w, [src1], 1 - ldrb data2w, [src2], 1 - subs limit, limit, 1 - ccmp data1w, data2w, 0, ne /* NZCV = 0b0000. */ - b.eq L(byte_loop) +L(less2): + mov result, 0 + tbz limit, 0, L(return_zero) + ldrb data1w, [src1end, -1] + ldrb data2w, [src2end, -1] sub result, data1w, data2w +L(return_zero): ret -END (__memcmp_aarch64) +L(loop_align): + ldp data1, data3, [src1, 16] + ldp data2, data4, [src2, 16] + cmp data1, data2 + ccmp data3, data4, 0, eq + b.ne L(return2) + + /* Align src2 and adjust src1, src2 and limit. */ + and tmp, src2, 15 + sub tmp, tmp, 16 + sub src2, src2, tmp + add limit, limit, tmp + sub src1, src1, tmp + sub limit, limit, 64 + 16 + + .p2align 4 +L(loop64): + ldr q0, [src1, 16] + ldr q1, [src2, 16] + subs limit, limit, 64 + ldr q2, [src1, 32] + ldr q3, [src2, 32] + eor v0.16b, v0.16b, v1.16b + eor v1.16b, v2.16b, v3.16b + ldr q2, [src1, 48] + ldr q3, [src2, 48] + umaxp v0.16b, v0.16b, v1.16b + ldr q4, [src1, 64]! + ldr q5, [src2, 64]! + eor v1.16b, v2.16b, v3.16b + eor v2.16b, v4.16b, v5.16b + umaxp v1.16b, v1.16b, v2.16b + umaxp v0.16b, v0.16b, v1.16b + umaxp v0.16b, v0.16b, v0.16b + fmov tmp, d0 + ccmp tmp, 0, 0, hi + b.eq L(loop64) + + /* If equal, process last 1-64 bytes using scalar loop. */ + add limit, limit, 64 + 16 + cbz tmp, L(last64) + + /* Determine the 8-byte aligned offset of the first difference. */ +#ifdef __AARCH64EB__ + rev16 tmp, tmp +#endif + rev tmp, tmp + clz tmp, tmp + bic tmp, tmp, 7 + sub tmp, tmp, 48 + ldr data1, [src1, tmp] + ldr data2, [src2, tmp] +#ifndef __AARCH64EB__ + rev data1, data1 + rev data2, data2 +#endif + mov result, 1 + cmp data1, data2 + cneg result, result, lo + ret +END (__memcmp_aarch64) |