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runtime/internal/atomic: Use power5 compatible instructions for ppc64

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This modifies a recent performance improvement to the
And8 and Or8 atomic functions which required both ppc64le
and ppc64 to use power8 instructions. Since then it was
decided that ppc64 (BE) should work for power5 and later.
This change uses instructions compatible with power5 for
ppc64 and uses power8 for ppc64le.

Fixes #16004

Change-Id: I623c75e8e6fd1fa063a53d250d86cdc9d0890dc7
Reviewed-on: https://go-review.googlesource.com/24181
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Lynn Boger 2016-06-16 14:57:45 -05:00 committed by Ian Lance Taylor
parent 05ecf53456
commit b75b0630fe
1 changed files with 47 additions and 4 deletions
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43
src/runtime/internal/atomic/asm_ppc64x.s
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@ -165,12 +165,32 @@ TEXT runtime∕internal∕atomic·Store64(SB), NOSPLIT, $0-16
TEXT runtime∕internal∕atomic·Or8(SB), NOSPLIT, $0-9
MOVD ptr+0(FP), R3
MOVBZ val+8(FP), R4
#ifdef GOARCH_ppc64
// Align ptr down to 4 bytes so we can use 32-bit load/store.
// R5 = (R3 << 0) & ~3
RLDCR $0, R3, $~3, R5
// Compute val shift.
// Big endian. ptr = ptr ^ 3
XOR $3, R3
// R6 = ((ptr & 3) * 8) = (ptr << 3) & (3*8)
RLDC $3, R3, $(3*8), R6
// Shift val for aligned ptr. R4 = val << R6
SLD R6, R4, R4
SYNC
again:
LWAR (R5), R6
OR R4, R6
STWCCC R6, (R5)
BNE again
#else
SYNC
again:
LBAR (R3), R6
OR R4, R6
STBCCC R6, (R3)
BNE again
#endif
ISYNC
RET
@ -178,11 +198,34 @@ again:
TEXT runtime∕internal∕atomic·And8(SB), NOSPLIT, $0-9
MOVD ptr+0(FP), R3
MOVBZ val+8(FP), R4
#ifdef GOARCH_ppc64
// Align ptr down to 4 bytes so we can use 32-bit load/store.
// R5 = (R3 << 0) & ~3
RLDCR $0, R3, $~3, R5
// Compute val shift.
// Big endian. ptr = ptr ^ 3
XOR $3, R3
// R6 = ((ptr & 3) * 8) = (ptr << 3) & (3*8)
RLDC $3, R3, $(3*8), R6
// Shift val for aligned ptr. R4 = val << R6 | ^(0xFF << R6)
MOVD $0xFF, R7
SLD R6, R4
SLD R6, R7
XOR $-1, R7
OR R7, R4
SYNC
again:
LWAR (R5), R6
AND R4, R6
STWCCC R6, (R5)
BNE again
#else
SYNC
again:
LBAR (R3),R6
AND R4,R6
STBCCC R6,(R3)
BNE again
#endif
ISYNC
RET