github.com/tcnksm/go@v0.0.0-20141208075154-439b32936367/src/math/asin_386.s (about)

     1  // Copyright 2010 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  // func Asin(x float64) float64
     8  TEXT ·Asin(SB),NOSPLIT,$0
     9  	FMOVD   x+0(FP), F0  // F0=sin(x)
    10  	FMOVD   F0, F1       // F0=sin(x), F1=sin(x)
    11  	FMULD   F0, F0       // F0=sin(x)*sin(x), F1=sin(x)
    12  	FLD1                 // F0=1, F1=sin(x)*sin(x), F2=sin(x)
    13  	FSUBRDP F0, F1       // F0=1-sin(x)*sin(x) (=cos(x)*cos(x)), F1=sin(x)
    14  	FSQRT                // F0=cos(x), F1=sin(x)
    15  	FPATAN               // F0=arcsin(sin(x))=x
    16  	FMOVDP  F0, ret+8(FP)
    17  	RET
    18  
    19  // func Acos(x float64) float64
    20  TEXT ·Acos(SB),NOSPLIT,$0
    21  	FMOVD   x+0(FP), F0  // F0=cos(x)
    22  	FMOVD   F0, F1       // F0=cos(x), F1=cos(x)
    23  	FMULD   F0, F0       // F0=cos(x)*cos(x), F1=cos(x)
    24  	FLD1                 // F0=1, F1=cos(x)*cos(x), F2=cos(x)
    25  	FSUBRDP F0, F1       // F0=1-cos(x)*cos(x) (=sin(x)*sin(x)), F1=cos(x)
    26  	FSQRT                // F0=sin(x), F1=cos(x)
    27  	FXCHD   F0, F1       // F0=cos(x), F1=sin(x)
    28  	FPATAN               // F0=arccos(cos(x))=x
    29  	FMOVDP	F0, ret+8(FP)
    30  	RET