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internal/bytealg: share code for IndexByte functions on arm

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Move the shared code of IndexByte and IndexByteString into
indexbytebody. This will allow to implement optimizations (e.g.
for #29001) in a single function.

Change-Id: I1d550da8eb65f95e492a460a12058cc35b1162b6
Reviewed-on: https://go-review.googlesource.com/c/go/+/167939
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Tobias Klauser 2019-03-17 22:39:42 +01:00 committed by Tobias Klauser
parent bedb6a18d8
commit 3496ff1d19
1 changed files with 17 additions and 25 deletions
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42
src/internal/bytealg/indexbyte_arm.s
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@ -9,46 +9,38 @@ TEXT ·IndexByte(SB),NOSPLIT,$0-20
MOVW b_base+0(FP), R0
MOVW b_len+4(FP), R1
MOVBU c+12(FP), R2 // byte to find
MOVW R0, R4 // store base for later
ADD R0, R1 // end
_loop:
CMP R0, R1
B.EQ _notfound
MOVBU.P 1(R0), R3
CMP R2, R3
B.NE _loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVW R0, ret+16(FP)
RET
_notfound:
MOVW $-1, R0
MOVW R0, ret+16(FP)
RET
MOVW $ret+16(FP), R5
B indexbytebody<>(SB)
TEXT ·IndexByteString(SB),NOSPLIT,$0-16
MOVW s_base+0(FP), R0
MOVW s_len+4(FP), R1
MOVBU c+8(FP), R2 // byte to find
MOVW $ret+12(FP), R5
B indexbytebody<>(SB)
// input:
// R0: data
// R1: data length
// R2: byte to find
// R5: address to put result
TEXT indexbytebody<>(SB),NOSPLIT,$0-0
MOVW R0, R4 // store base for later
ADD R0, R1 // end
_sib_loop:
loop:
CMP R0, R1
B.EQ _sib_notfound
B.EQ notfound
MOVBU.P 1(R0), R3
CMP R2, R3
B.NE _sib_loop
B.NE loop
SUB $1, R0 // R0 will be one beyond the position we want
SUB R4, R0 // remove base
MOVW R0, ret+12(FP)
MOVW R0, (R5)
RET
_sib_notfound:
notfound:
MOVW $-1, R0
MOVW R0, ret+12(FP)
MOVW R0, (R5)
RET