| // 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 |