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math/big: Unify divWW implementation for ppc64 and ppc64le.

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Starting in go1.9, the minimum processor requirement for ppc64 is POWER8. So it
may now use the same divWW implementation as ppc64le.

Updates #19074

Change-Id: If1a85f175cda89eee06a1024ccd468da6124c844
Reviewed-on: https://go-review.googlesource.com/39010
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
This commit is contained in:
Carlos Eduardo Seo 2017-03-30 18:30:07 -03:00 committed by Lynn Boger
parent 5a45a157f2
commit 4a1140472b
3 changed files with 39 additions and 64 deletions
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14
src/math/big/arith_ppc64.s
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@ -1,14 +0,0 @@
// Copyright 2016 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.
// +build !math_big_pure_go,ppc64
#include "textflag.h"
// This file provides fast assembly versions for the elementary
// arithmetic operations on vectors implemented in arith.go.
TEXT ·divWW(SB), NOSPLIT, $0
BR ·divWW_g(SB)

50
src/math/big/arith_ppc64le.s
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@ -1,50 +0,0 @@
// Copyright 2016 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.
// +build !math_big_pure_go,ppc64le
#include "textflag.h"
// This file provides fast assembly versions for the elementary
// arithmetic operations on vectors implemented in arith.go.
// func divWW(x1, x0, y Word) (q, r Word)
TEXT ·divWW(SB), NOSPLIT, $0
MOVD x1+0(FP), R4
MOVD x0+8(FP), R5
MOVD y+16(FP), R6
CMPU R4, R6
BGE divbigger
// from the programmer's note in ch. 3 of the ISA manual, p.74
DIVDEU R6, R4, R3
DIVDU R6, R5, R7
MULLD R6, R3, R8
MULLD R6, R7, R20
SUB R20, R5, R10
ADD R7, R3, R3
SUB R8, R10, R4
CMPU R4, R10
BLT adjust
CMPU R4, R6
BLT end
adjust:
MOVD $1, R21
ADD R21, R3, R3
SUB R6, R4, R4
end:
MOVD R3, q+24(FP)
MOVD R4, r+32(FP)
RET
divbigger:
MOVD $-1, R7
MOVD R7, q+24(FP)
MOVD R7, r+32(FP)
RET

39
src/math/big/arith_ppc64x.s
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@ -173,5 +173,44 @@ end:
MOVD R4, c+56(FP) MOVD R4, c+56(FP)
RET RET
// func divWW(x1, x0, y Word) (q, r Word)
TEXT ·divWW(SB), NOSPLIT, $0
MOVD x1+0(FP), R4
MOVD x0+8(FP), R5
MOVD y+16(FP), R6
CMPU R4, R6
BGE divbigger
// from the programmer's note in ch. 3 of the ISA manual, p.74
DIVDEU R6, R4, R3
DIVDU R6, R5, R7
MULLD R6, R3, R8
MULLD R6, R7, R20
SUB R20, R5, R10
ADD R7, R3, R3
SUB R8, R10, R4
CMPU R4, R10
BLT adjust
CMPU R4, R6
BLT end
adjust:
MOVD $1, R21
ADD R21, R3, R3
SUB R6, R4, R4
end:
MOVD R3, q+24(FP)
MOVD R4, r+32(FP)
RET
divbigger:
MOVD $-1, R7
MOVD R7, q+24(FP)
MOVD R7, r+32(FP)
RET
TEXT ·divWVW(SB), NOSPLIT, $0 TEXT ·divWVW(SB), NOSPLIT, $0
BR ·divWVW_g(SB) BR ·divWVW_g(SB)