floor_amd64.s

Documentation: math

		 1// Copyright 2012 The Go Authors. All rights reserved.
		 2// Use of this source code is governed by a BSD-style
		 3// license that can be found in the LICENSE file.
		 4
		 5#include "textflag.h"
		 6
		 7#define Big		0x4330000000000000 // 2**52
		 8
		 9// func archFloor(x float64) float64
		10TEXT ·archFloor(SB),NOSPLIT,$0
		11	MOVQ	x+0(FP), AX
		12	MOVQ	$~(1<<63), DX // sign bit mask
		13	ANDQ	AX,DX // DX = |x|
		14	SUBQ	$1,DX
		15	MOVQ		$(Big - 1), CX // if |x| >= 2**52-1 or IsNaN(x) or |x| == 0, return x
		16	CMPQ	DX,CX
		17	JAE		 isBig_floor
		18	MOVQ	AX, X0 // X0 = x
		19	CVTTSD2SQ	X0, AX
		20	CVTSQ2SD	AX, X1 // X1 = float(int(x))
		21	CMPSD	X1, X0, 1 // compare LT; X0 = 0xffffffffffffffff or 0
		22	MOVSD	$(-1.0), X2
		23	ANDPD	X2, X0 // if x < float(int(x)) {X0 = -1} else {X0 = 0}
		24	ADDSD	X1, X0
		25	MOVSD	X0, ret+8(FP)
		26	RET
		27isBig_floor:
		28	MOVQ		AX, ret+8(FP) // return x
		29	RET
		30
		31// func archCeil(x float64) float64
		32TEXT ·archCeil(SB),NOSPLIT,$0
		33	MOVQ	x+0(FP), AX
		34	MOVQ	$~(1<<63), DX // sign bit mask
		35	MOVQ	AX, BX // BX = copy of x
		36	ANDQ		DX, BX // BX = |x|
		37	MOVQ		$Big, CX // if |x| >= 2**52 or IsNaN(x), return x
		38	CMPQ		BX, CX
		39	JAE		 isBig_ceil
		40	MOVQ	AX, X0 // X0 = x
		41	MOVQ	DX, X2 // X2 = sign bit mask
		42	CVTTSD2SQ	X0, AX
		43	ANDNPD	X0, X2 // X2 = sign
		44	CVTSQ2SD	AX, X1	// X1 = float(int(x))
		45	CMPSD	X1, X0, 2 // compare LE; X0 = 0xffffffffffffffff or 0
		46	ORPD	X2, X1 // if X1 = 0.0, incorporate sign
		47	MOVSD	$1.0, X3
		48	ANDNPD	X3, X0
		49	ORPD	X2, X0 // if float(int(x)) <= x {X0 = 1} else {X0 = -0}
		50	ADDSD	X1, X0
		51	MOVSD	X0, ret+8(FP)
		52	RET
		53isBig_ceil:
		54	MOVQ	AX, ret+8(FP)
		55	RET
		56
		57// func archTrunc(x float64) float64
		58TEXT ·archTrunc(SB),NOSPLIT,$0
		59	MOVQ	x+0(FP), AX
		60	MOVQ	$~(1<<63), DX // sign bit mask
		61	MOVQ	AX, BX // BX = copy of x
		62	ANDQ		DX, BX // BX = |x|
		63	MOVQ		$Big, CX // if |x| >= 2**52 or IsNaN(x), return x
		64	CMPQ		BX, CX
		65	JAE		 isBig_trunc
		66	MOVQ	AX, X0
		67	MOVQ	DX, X2 // X2 = sign bit mask
		68	CVTTSD2SQ	X0, AX
		69	ANDNPD	X0, X2 // X2 = sign
		70	CVTSQ2SD	AX, X0 // X0 = float(int(x))
		71	ORPD	X2, X0 // if X0 = 0.0, incorporate sign
		72	MOVSD	X0, ret+8(FP)
		73	RET
		74isBig_trunc:
		75	MOVQ		AX, ret+8(FP) // return x
		76	RET
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