| // 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 "textflag.h" |
| |
| // func Asin(x float64) float64 |
| TEXT ·Asin(SB),NOSPLIT,$0 |
| FMOVD x+0(FP), F0 // F0=sin(x) |
| FMOVD F0, F1 // F0=sin(x), F1=sin(x) |
| FMULD F0, F0 // F0=sin(x)*sin(x), F1=sin(x) |
| FLD1 // F0=1, F1=sin(x)*sin(x), F2=sin(x) |
| FSUBRDP F0, F1 // F0=1-sin(x)*sin(x) (=cos(x)*cos(x)), F1=sin(x) |
| FSQRT // F0=cos(x), F1=sin(x) |
| FPATAN // F0=arcsin(sin(x))=x |
| FMOVDP F0, ret+8(FP) |
| RET |
| |
| // func Acos(x float64) float64 |
| TEXT ·Acos(SB),NOSPLIT,$0 |
| FMOVD x+0(FP), F0 // F0=cos(x) |
| FMOVD F0, F1 // F0=cos(x), F1=cos(x) |
| FMULD F0, F0 // F0=cos(x)*cos(x), F1=cos(x) |
| FLD1 // F0=1, F1=cos(x)*cos(x), F2=cos(x) |
| FSUBRDP F0, F1 // F0=1-cos(x)*cos(x) (=sin(x)*sin(x)), F1=cos(x) |
| FSQRT // F0=sin(x), F1=cos(x) |
| FXCHD F0, F1 // F0=cos(x), F1=sin(x) |
| FPATAN // F0=arccos(cos(x))=x |
| FMOVDP F0, ret+8(FP) |
| RET |
