| // 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 Tan(x float64) float64 |
| TEXT ·Tan(SB),NOSPLIT,$0 |
| FMOVD x+0(FP), F0 // F0=x |
| FPTAN // F0=1, F1=tan(x) if -2**63 < x < 2**63 |
| FSTSW AX // AX=status word |
| ANDW $0x0400, AX |
| JNE 4(PC) // jump if x outside range |
| FMOVDP F0, F0 // F0=tan(x) |
| FMOVDP F0, ret+8(FP) |
| RET |
| FLDPI // F0=Pi, F1=x |
| FADDD F0, F0 // F0=2*Pi, F1=x |
| FXCHD F0, F1 // F0=x, F1=2*Pi |
| FPREM1 // F0=reduced_x, F1=2*Pi |
| FSTSW AX // AX=status word |
| ANDW $0x0400, AX |
| JNE -3(PC) // jump if reduction incomplete |
| FMOVDP F0, F1 // F0=reduced_x |
| FPTAN // F0=1, F1=tan(reduced_x) |
| FMOVDP F0, F0 // F0=tan(reduced_x) |
| FMOVDP F0, ret+8(FP) |
| RET |
