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Diffstat (limited to '')
| -rw-r--r-- | src/internal/bytealg/equal_arm64.s | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/src/internal/bytealg/equal_arm64.s b/src/internal/bytealg/equal_arm64.s new file mode 100644 index 0000000..01aa7b7 --- /dev/null +++ b/src/internal/bytealg/equal_arm64.s @@ -0,0 +1,136 @@ +// Copyright 2018 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#include "go_asm.h" +#include "textflag.h" + +// memequal(a, b unsafe.Pointer, size uintptr) bool +TEXT runtime·memequal(SB),NOSPLIT|NOFRAME,$0-25 + MOVD size+16(FP), R1 + // short path to handle 0-byte case + CBZ R1, equal + MOVD a+0(FP), R0 + MOVD b+8(FP), R2 + MOVD $ret+24(FP), R8 + B memeqbody<>(SB) +equal: + MOVD $1, R0 + MOVB R0, ret+24(FP) + RET + +// memequal_varlen(a, b unsafe.Pointer) bool +TEXT runtime·memequal_varlen(SB),NOSPLIT,$40-17 + MOVD a+0(FP), R3 + MOVD b+8(FP), R4 + CMP R3, R4 + BEQ eq + MOVD 8(R26), R5 // compiler stores size at offset 8 in the closure + CBZ R5, eq + MOVD R3, 8(RSP) + MOVD R4, 16(RSP) + MOVD R5, 24(RSP) + BL runtime·memequal(SB) + MOVBU 32(RSP), R3 + MOVB R3, ret+16(FP) + RET +eq: + MOVD $1, R3 + MOVB R3, ret+16(FP) + RET + +// input: +// R0: pointer a +// R1: data len +// R2: pointer b +// R8: address to put result +TEXT memeqbody<>(SB),NOSPLIT,$0 + CMP $1, R1 + // handle 1-byte special case for better performance + BEQ one + CMP $16, R1 + // handle specially if length < 16 + BLO tail + BIC $0x3f, R1, R3 + CBZ R3, chunk16 + // work with 64-byte chunks + ADD R3, R0, R6 // end of chunks +chunk64_loop: + VLD1.P (R0), [V0.D2, V1.D2, V2.D2, V3.D2] + VLD1.P (R2), [V4.D2, V5.D2, V6.D2, V7.D2] + VCMEQ V0.D2, V4.D2, V8.D2 + VCMEQ V1.D2, V5.D2, V9.D2 + VCMEQ V2.D2, V6.D2, V10.D2 + VCMEQ V3.D2, V7.D2, V11.D2 + VAND V8.B16, V9.B16, V8.B16 + VAND V8.B16, V10.B16, V8.B16 + VAND V8.B16, V11.B16, V8.B16 + CMP R0, R6 + VMOV V8.D[0], R4 + VMOV V8.D[1], R5 + CBZ R4, not_equal + CBZ R5, not_equal + BNE chunk64_loop + AND $0x3f, R1, R1 + CBZ R1, equal +chunk16: + // work with 16-byte chunks + BIC $0xf, R1, R3 + CBZ R3, tail + ADD R3, R0, R6 // end of chunks +chunk16_loop: + LDP.P 16(R0), (R4, R5) + LDP.P 16(R2), (R7, R9) + EOR R4, R7 + CBNZ R7, not_equal + EOR R5, R9 + CBNZ R9, not_equal + CMP R0, R6 + BNE chunk16_loop + AND $0xf, R1, R1 + CBZ R1, equal +tail: + // special compare of tail with length < 16 + TBZ $3, R1, lt_8 + MOVD (R0), R4 + MOVD (R2), R5 + EOR R4, R5 + CBNZ R5, not_equal + SUB $8, R1, R6 // offset of the last 8 bytes + MOVD (R0)(R6), R4 + MOVD (R2)(R6), R5 + EOR R4, R5 + CBNZ R5, not_equal + B equal +lt_8: + TBZ $2, R1, lt_4 + MOVWU (R0), R4 + MOVWU (R2), R5 + EOR R4, R5 + CBNZ R5, not_equal + SUB $4, R1, R6 // offset of the last 4 bytes + MOVWU (R0)(R6), R4 + MOVWU (R2)(R6), R5 + EOR R4, R5 + CBNZ R5, not_equal + B equal +lt_4: + TBZ $1, R1, lt_2 + MOVHU.P 2(R0), R4 + MOVHU.P 2(R2), R5 + CMP R4, R5 + BNE not_equal +lt_2: + TBZ $0, R1, equal +one: + MOVBU (R0), R4 + MOVBU (R2), R5 + CMP R4, R5 + BNE not_equal +equal: + MOVD $1, R0 + MOVB R0, (R8) + RET +not_equal: + MOVB ZR, (R8) + RET |