root/src/pkg/math/floor_386.s

// Copyright 2010 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 "../../cmd/ld/textflag.h"

// func Ceil(x float64) float64
TEXT ·Ceil(SB),NOSPLIT,$0
        FMOVD   x+0(FP), F0  // F0=x
        FSTCW   -2(SP)       // save old Control Word
        MOVW    -2(SP), AX
        ANDW    $0xf3ff, AX
        ORW     $0x0800, AX  // Rounding Control set to +Inf
        MOVW    AX, -4(SP)   // store new Control Word
        FLDCW   -4(SP)       // load new Control Word
        FRNDINT              // F0=Ceil(x)
        FLDCW   -2(SP)       // load old Control Word
        FMOVDP  F0, ret+8(FP)
        RET

// func Floor(x float64) float64
TEXT ·Floor(SB),NOSPLIT,$0
        FMOVD   x+0(FP), F0  // F0=x
        FSTCW   -2(SP)       // save old Control Word
        MOVW    -2(SP), AX
        ANDW    $0xf3ff, AX
        ORW     $0x0400, AX  // Rounding Control set to -Inf
        MOVW    AX, -4(SP)   // store new Control Word
        FLDCW   -4(SP)       // load new Control Word
        FRNDINT              // F0=Floor(x)
        FLDCW   -2(SP)       // load old Control Word
        FMOVDP  F0, ret+8(FP)
        RET

// func Trunc(x float64) float64
TEXT ·Trunc(SB),NOSPLIT,$0
        FMOVD   x+0(FP), F0  // F0=x
        FSTCW   -2(SP)       // save old Control Word
        MOVW    -2(SP), AX
        ORW     $0x0c00, AX  // Rounding Control set to truncate
        MOVW    AX, -4(SP)   // store new Control Word
        FLDCW   -4(SP)       // load new Control Word
        FRNDINT              // F0=Trunc(x)
        FLDCW   -2(SP)       // load old Control Word
        FMOVDP  F0, ret+8(FP)
        RET