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Diffstat (limited to 'src/internal/bytealg/equal_arm64.s')
| -rw-r--r-- | src/internal/bytealg/equal_arm64.s | 121 |
1 files changed, 121 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..d3aabba --- /dev/null +++ b/src/internal/bytealg/equal_arm64.s @@ -0,0 +1,121 @@ +// 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<ABIInternal>(SB),NOSPLIT|NOFRAME,$0-25 + // short path to handle 0-byte case + CBZ R2, equal + B memeqbody<>(SB) +equal: + MOVD $1, R0 + RET + +// memequal_varlen(a, b unsafe.Pointer) bool +TEXT runtime·memequal_varlen<ABIInternal>(SB),NOSPLIT,$0-17 + CMP R0, R1 + BEQ eq + MOVD 8(R26), R2 // compiler stores size at offset 8 in the closure + CBZ R2, eq + B memeqbody<>(SB) +eq: + MOVD $1, R0 + RET + +// input: +// R0: pointer a +// R1: pointer b +// R2: data len +// at return: result in R0 +TEXT memeqbody<>(SB),NOSPLIT,$0 + CMP $1, R2 + // handle 1-byte special case for better performance + BEQ one + CMP $16, R2 + // handle specially if length < 16 + BLO tail + BIC $0x3f, R2, 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 (R1), [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, R2, R2 + CBZ R2, equal +chunk16: + // work with 16-byte chunks + BIC $0xf, R2, R3 + CBZ R3, tail + ADD R3, R0, R6 // end of chunks +chunk16_loop: + LDP.P 16(R0), (R4, R5) + LDP.P 16(R1), (R7, R9) + EOR R4, R7 + CBNZ R7, not_equal + EOR R5, R9 + CBNZ R9, not_equal + CMP R0, R6 + BNE chunk16_loop + AND $0xf, R2, R2 + CBZ R2, equal +tail: + // special compare of tail with length < 16 + TBZ $3, R2, lt_8 + MOVD (R0), R4 + MOVD (R1), R5 + EOR R4, R5 + CBNZ R5, not_equal + SUB $8, R2, R6 // offset of the last 8 bytes + MOVD (R0)(R6), R4 + MOVD (R1)(R6), R5 + EOR R4, R5 + CBNZ R5, not_equal + B equal +lt_8: + TBZ $2, R2, lt_4 + MOVWU (R0), R4 + MOVWU (R1), R5 + EOR R4, R5 + CBNZ R5, not_equal + SUB $4, R2, R6 // offset of the last 4 bytes + MOVWU (R0)(R6), R4 + MOVWU (R1)(R6), R5 + EOR R4, R5 + CBNZ R5, not_equal + B equal +lt_4: + TBZ $1, R2, lt_2 + MOVHU.P 2(R0), R4 + MOVHU.P 2(R1), R5 + CMP R4, R5 + BNE not_equal +lt_2: + TBZ $0, R2, equal +one: + MOVBU (R0), R4 + MOVBU (R1), R5 + CMP R4, R5 + BNE not_equal +equal: + MOVD $1, R0 + RET +not_equal: + MOVB ZR, R0 + RET |