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// Copyright 2017 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"
// Minimax polynomial approximations
DATA ·tanrodataL13<> + 0(SB)/8, $0.181017336383229927e-07
DATA ·tanrodataL13<> + 8(SB)/8, $-.256590857271311164e-03
DATA ·tanrodataL13<> + 16(SB)/8, $-.464359274328689195e+00
DATA ·tanrodataL13<> + 24(SB)/8, $1.0
DATA ·tanrodataL13<> + 32(SB)/8, $-.333333333333333464e+00
DATA ·tanrodataL13<> + 40(SB)/8, $0.245751217306830032e-01
DATA ·tanrodataL13<> + 48(SB)/8, $-.245391301343844510e-03
DATA ·tanrodataL13<> + 56(SB)/8, $0.214530914428992319e-01
DATA ·tanrodataL13<> + 64(SB)/8, $0.108285667160535624e-31
DATA ·tanrodataL13<> + 72(SB)/8, $0.612323399573676480e-16
DATA ·tanrodataL13<> + 80(SB)/8, $0.157079632679489656e+01
DATA ·tanrodataL13<> + 88(SB)/8, $0.636619772367581341e+00
GLOBL ·tanrodataL13<> + 0(SB), RODATA, $96
// Constants
DATA ·tanxnan<> + 0(SB)/8, $0x7ff8000000000000
GLOBL ·tanxnan<> + 0(SB), RODATA, $8
DATA ·tanxlim<> + 0(SB)/8, $0x432921fb54442d19
GLOBL ·tanxlim<> + 0(SB), RODATA, $8
DATA ·tanxadd<> + 0(SB)/8, $0xc338000000000000
GLOBL ·tanxadd<> + 0(SB), RODATA, $8
// Tan returns the tangent of the radian argument.
//
// Special cases are:
// Tan(±0) = ±0
// Tan(±Inf) = NaN
// Tan(NaN) = NaN
// The algorithm used is minimax polynomial approximation using a table of
// polynomial coefficients determined with a Remez exchange algorithm.
TEXT ·tanAsm(SB), NOSPLIT, $0-16
FMOVD x+0(FP), F0
//specail case Tan(±0) = ±0
FMOVD $(0.0), F1
FCMPU F0, F1
BEQ atanIsZero
MOVD $·tanrodataL13<>+0(SB), R5
LTDBR F0, F0
BLTU L10
FMOVD F0, F2
L2:
MOVD $·tanxlim<>+0(SB), R1
WORD $0xED201000 //cdb %f2,0(%r1)
BYTE $0x00
BYTE $0x19
BGE L11
BVS L11
MOVD $·tanxadd<>+0(SB), R1
FMOVD 88(R5), F6
FMOVD 0(R1), F4
WFMSDB V0, V6, V4, V6
FMOVD 80(R5), F1
FADD F6, F4
FMOVD 72(R5), F2
FMSUB F1, F4, F0
FMOVD 64(R5), F3
WFMADB V4, V2, V0, V2
FMOVD 56(R5), F1
WFMADB V4, V3, V2, V4
FMUL F2, F2
VLEG $0, 48(R5), V18
LGDR F6, R1
FMOVD 40(R5), F5
FMOVD 32(R5), F3
FMADD F1, F2, F3
FMOVD 24(R5), F1
FMOVD 16(R5), F7
FMOVD 8(R5), F0
WFMADB V2, V7, V1, V7
WFMADB V2, V0, V5, V0
WFMDB V2, V2, V1
FMOVD 0(R5), F5
WFLCDB V4, V16
WFMADB V2, V5, V18, V5
WFMADB V1, V0, V7, V0
TMLL R1, $1
WFMADB V1, V5, V3, V1
BNE L12
WFDDB V0, V1, V0
WFMDB V2, V16, V2
WFMADB V2, V0, V4, V0
WORD $0xB3130000 //lcdbr %f0,%f0
FMOVD F0, ret+8(FP)
RET
L12:
WFMSDB V2, V1, V0, V2
WFMDB V16, V2, V2
FDIV F2, F0
FMOVD F0, ret+8(FP)
RET
L11:
MOVD $·tanxnan<>+0(SB), R1
FMOVD 0(R1), F0
FMOVD F0, ret+8(FP)
RET
L10:
WORD $0xB3130020 //lcdbr %f2,%f0
BR L2
atanIsZero:
FMOVD F0, ret+8(FP)
RET
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