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Diffstat (limited to 'src/math/floor_amd64.s')
| -rw-r--r-- | src/math/floor_amd64.s | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/src/math/floor_amd64.s b/src/math/floor_amd64.s new file mode 100644 index 000000000..67b7cdec0 --- /dev/null +++ b/src/math/floor_amd64.s @@ -0,0 +1,76 @@ +// Copyright 2012 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 "textflag.h" + +#define Big 0x4330000000000000 // 2**52 + +// func Floor(x float64) float64 +TEXT ·Floor(SB),NOSPLIT,$0 + MOVQ x+0(FP), AX + MOVQ $~(1<<63), DX // sign bit mask + ANDQ AX,DX // DX = |x| + SUBQ $1,DX + MOVQ $(Big - 1), CX // if |x| >= 2**52-1 or IsNaN(x) or |x| == 0, return x + CMPQ DX,CX + JAE isBig_floor + MOVQ AX, X0 // X0 = x + CVTTSD2SQ X0, AX + CVTSQ2SD AX, X1 // X1 = float(int(x)) + CMPSD X1, X0, 1 // compare LT; X0 = 0xffffffffffffffff or 0 + MOVSD $(-1.0), X2 + ANDPD X2, X0 // if x < float(int(x)) {X0 = -1} else {X0 = 0} + ADDSD X1, X0 + MOVSD X0, ret+8(FP) + RET +isBig_floor: + MOVQ AX, ret+8(FP) // return x + RET + +// func Ceil(x float64) float64 +TEXT ·Ceil(SB),NOSPLIT,$0 + MOVQ x+0(FP), AX + MOVQ $~(1<<63), DX // sign bit mask + MOVQ AX, BX // BX = copy of x + ANDQ DX, BX // BX = |x| + MOVQ $Big, CX // if |x| >= 2**52 or IsNaN(x), return x + CMPQ BX, CX + JAE isBig_ceil + MOVQ AX, X0 // X0 = x + MOVQ DX, X2 // X2 = sign bit mask + CVTTSD2SQ X0, AX + ANDNPD X0, X2 // X2 = sign + CVTSQ2SD AX, X1 // X1 = float(int(x)) + CMPSD X1, X0, 2 // compare LE; X0 = 0xffffffffffffffff or 0 + ORPD X2, X1 // if X1 = 0.0, incorporate sign + MOVSD $1.0, X3 + ANDNPD X3, X0 + ORPD X2, X0 // if float(int(x)) <= x {X0 = 1} else {X0 = -0} + ADDSD X1, X0 + MOVSD X0, ret+8(FP) + RET +isBig_ceil: + MOVQ AX, ret+8(FP) + RET + +// func Trunc(x float64) float64 +TEXT ·Trunc(SB),NOSPLIT,$0 + MOVQ x+0(FP), AX + MOVQ $~(1<<63), DX // sign bit mask + MOVQ AX, BX // BX = copy of x + ANDQ DX, BX // BX = |x| + MOVQ $Big, CX // if |x| >= 2**52 or IsNaN(x), return x + CMPQ BX, CX + JAE isBig_trunc + MOVQ AX, X0 + MOVQ DX, X2 // X2 = sign bit mask + CVTTSD2SQ X0, AX + ANDNPD X0, X2 // X2 = sign + CVTSQ2SD AX, X0 // X0 = float(int(x)) + ORPD X2, X0 // if X0 = 0.0, incorporate sign + MOVSD X0, ret+8(FP) + RET +isBig_trunc: + MOVQ AX, ret+8(FP) // return x + RET |