mirror of https://github.com/golang/go.git
Revert "bytes: add optimized Compare for arm64"
This reverts commit bfa8b6f8ff.
Reason for revert: This depends on another CL which is not yet submitted.
Change-Id: I50e7594f1473c911a2079fe910849a6694ac6c07
Reviewed-on: https://go-review.googlesource.com/101496
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Cherry Zhang
parent
bfa8b6f8ff
commit
e22d24131c
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@ -10,7 +10,7 @@ TEXT ·Compare(SB),NOSPLIT|NOFRAME,$0-56
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MOVD a_len+8(FP), R0
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MOVD b_base+24(FP), R3
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MOVD b_len+32(FP), R1
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MOVD $ret+48(FP), R7
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ADD $56, RSP, R7
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B cmpbody<>(SB)
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TEXT bytes·Compare(SB),NOSPLIT|NOFRAME,$0-56
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@ -18,7 +18,7 @@ TEXT bytes·Compare(SB),NOSPLIT|NOFRAME,$0-56
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MOVD a_len+8(FP), R0
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MOVD b_base+24(FP), R3
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MOVD b_len+32(FP), R1
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MOVD $ret+48(FP), R7
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ADD $56, RSP, R7
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B cmpbody<>(SB)
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TEXT runtime·cmpstring(SB),NOSPLIT|NOFRAME,$0-40
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@ -26,7 +26,7 @@ TEXT runtime·cmpstring(SB),NOSPLIT|NOFRAME,$0-40
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MOVD a_len+8(FP), R0
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MOVD b_base+16(FP), R3
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MOVD b_len+24(FP), R1
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MOVD $ret+32(FP), R7
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ADD $40, RSP, R7
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B cmpbody<>(SB)
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// On entry:
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@ -37,98 +37,30 @@ TEXT runtime·cmpstring(SB),NOSPLIT|NOFRAME,$0-40
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// R7 points to return value (-1/0/1 will be written here)
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//
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// On exit:
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// R4, R5, R6, R8, R9 and R10 are clobbered
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// R4, R5, and R6 are clobbered
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TEXT cmpbody<>(SB),NOSPLIT|NOFRAME,$0-0
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CMP R2, R3
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BEQ samebytes // same starting pointers; compare lengths
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CMP R0, R1
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CSEL LT, R1, R0, R6 // R6 is min(R0, R1)
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CMP $0, R6
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BEQ samebytes
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BIC $0xf, R6, R10
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CBZ R10, small // length < 16
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ADD R2, R10 // end of chunk16
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// length >= 16
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chunk16_loop:
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LDP.P 16(R2), (R4, R8)
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LDP.P 16(R3), (R5, R9)
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ADD R2, R6 // R2 is current byte in a, R6 is last byte in a to compare
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loop:
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CMP R2, R6
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BEQ samebytes // all compared bytes were the same; compare lengths
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MOVBU.P 1(R2), R4
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MOVBU.P 1(R3), R5
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CMP R4, R5
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BNE cmp
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CMP R8, R9
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BNE cmpnext
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CMP R10, R2
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BNE chunk16_loop
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AND $0xf, R6, R6
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CBZ R6, samebytes
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SUBS $8, R6
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BLT tail
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// the length of tail > 8 bytes
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MOVD.P 8(R2), R4
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MOVD.P 8(R3), R5
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CMP R4, R5
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BNE cmp
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SUB $8, R6
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// compare last 8 bytes
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tail:
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MOVD (R2)(R6), R4
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MOVD (R3)(R6), R5
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CMP R4, R5
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BEQ samebytes
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cmp:
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REV R4, R4
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REV R5, R5
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CMP R4, R5
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ret:
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BEQ loop
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// bytes differed
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MOVD $1, R4
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CNEG HI, R4, R4
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CSNEG LT, R4, R4, R4
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MOVD R4, (R7)
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RET
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small:
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TBZ $3, R6, lt_8
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MOVD (R2), R4
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MOVD (R3), R5
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CMP R4, R5
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BNE cmp
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SUBS $8, R6
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BEQ samebytes
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ADD $8, R2
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ADD $8, R3
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SUB $8, R6
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B tail
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lt_8:
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TBZ $2, R6, lt_4
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MOVWU (R2), R4
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MOVWU (R3), R5
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CMPW R4, R5
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BNE cmp
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SUBS $4, R6
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BEQ samebytes
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ADD $4, R2
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ADD $4, R3
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lt_4:
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TBZ $1, R6, lt_2
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MOVHU (R2), R4
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MOVHU (R3), R5
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CMPW R4, R5
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BNE cmp
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ADD $2, R2
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ADD $2, R3
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lt_2:
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TBZ $0, R6, samebytes
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one:
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MOVBU (R2), R4
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MOVBU (R3), R5
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CMPW R4, R5
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BNE ret
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samebytes:
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CMP R1, R0
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CSET NE, R4
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CNEG LO, R4, R4
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MOVD $1, R4
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CMP R0, R1
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CSNEG LT, R4, R4, R4
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CSEL EQ, ZR, R4, R4
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MOVD R4, (R7)
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RET
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cmpnext:
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REV R8, R4
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REV R9, R5
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CMP R4, R5
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B ret
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