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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
|
|
