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// 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
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