1 // Copyright 2017 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 #include "textflag.h" 6 7 // Minimax polynomial approximations 8 DATA tanrodataL13<> + 0(SB)/8, $0.181017336383229927e-07 9 DATA tanrodataL13<> + 8(SB)/8, $-.256590857271311164e-03 10 DATA tanrodataL13<> + 16(SB)/8, $-.464359274328689195e+00 11 DATA tanrodataL13<> + 24(SB)/8, $1.0 12 DATA tanrodataL13<> + 32(SB)/8, $-.333333333333333464e+00 13 DATA tanrodataL13<> + 40(SB)/8, $0.245751217306830032e-01 14 DATA tanrodataL13<> + 48(SB)/8, $-.245391301343844510e-03 15 DATA tanrodataL13<> + 56(SB)/8, $0.214530914428992319e-01 16 DATA tanrodataL13<> + 64(SB)/8, $0.108285667160535624e-31 17 DATA tanrodataL13<> + 72(SB)/8, $0.612323399573676480e-16 18 DATA tanrodataL13<> + 80(SB)/8, $0.157079632679489656e+01 19 DATA tanrodataL13<> + 88(SB)/8, $0.636619772367581341e+00 20 GLOBL tanrodataL13<> + 0(SB), RODATA, $96 21 22 // Constants 23 DATA tanxnan<> + 0(SB)/8, $0x7ff8000000000000 24 GLOBL tanxnan<> + 0(SB), RODATA, $8 25 DATA tanxlim<> + 0(SB)/8, $0x432921fb54442d19 26 GLOBL tanxlim<> + 0(SB), RODATA, $8 27 DATA tanxadd<> + 0(SB)/8, $0xc338000000000000 28 GLOBL tanxadd<> + 0(SB), RODATA, $8 29 30 // Tan returns the tangent of the radian argument. 31 // 32 // Special cases are: 33 // Tan(0) = 0 34 // Tan(Inf) = NaN 35 // Tan(NaN) = NaN 36 // The algorithm used is minimax polynomial approximation using a table of 37 // polynomial coefficients determined with a Remez exchange algorithm. 38 39 TEXT tanAsm(SB), NOSPLIT, $0-16 40 FMOVD x+0(FP), F0 41 //specail case Tan(0) = 0 42 FMOVD $(0.0), F1 43 FCMPU F0, F1 44 BEQ atanIsZero 45 46 MOVD $tanrodataL13<>+0(SB), R5 47 WORD $0xB3120000 //ltdbr %f0,%f0 48 BLTU L10 49 FMOVD F0, F2 50 L2: 51 MOVD $tanxlim<>+0(SB), R1 52 WORD $0xED201000 //cdb %f2,0(%r1) 53 BYTE $0x00 54 BYTE $0x19 55 BGE L11 56 BVS L11 57 MOVD $tanxadd<>+0(SB), R1 58 FMOVD 88(R5), F6 59 FMOVD 0(R1), F4 60 WFMSDB V0, V6, V4, V6 61 FMOVD 80(R5), F1 62 FADD F6, F4 63 FMOVD 72(R5), F2 64 FMSUB F1, F4, F0 65 FMOVD 64(R5), F3 66 WFMADB V4, V2, V0, V2 67 FMOVD 56(R5), F1 68 WFMADB V4, V3, V2, V4 69 FMUL F2, F2 70 VLEG $0, 48(R5), V18 71 WORD $0xB3CD0016 //lgdr %r1,%f6 72 FMOVD 40(R5), F5 73 FMOVD 32(R5), F3 74 FMADD F1, F2, F3 75 FMOVD 24(R5), F1 76 FMOVD 16(R5), F7 77 FMOVD 8(R5), F0 78 WFMADB V2, V7, V1, V7 79 WFMADB V2, V0, V5, V0 80 WFMDB V2, V2, V1 81 FMOVD 0(R5), F5 82 WFLCDB V4, V16 83 WFMADB V2, V5, V18, V5 84 WFMADB V1, V0, V7, V0 85 WORD $0xA7110001 //tmll %r1,1 86 WFMADB V1, V5, V3, V1 87 BNE L12 88 WFDDB V0, V1, V0 89 WFMDB V2, V16, V2 90 WFMADB V2, V0, V4, V0 91 WORD $0xB3130000 //lcdbr %f0,%f0 92 FMOVD F0, ret+8(FP) 93 RET 94 L12: 95 WFMSDB V2, V1, V0, V2 96 WFMDB V16, V2, V2 97 FDIV F2, F0 98 FMOVD F0, ret+8(FP) 99 RET 100 L11: 101 MOVD $tanxnan<>+0(SB), R1 102 FMOVD 0(R1), F0 103 FMOVD F0, ret+8(FP) 104 RET 105 L10: 106 WORD $0xB3130020 //lcdbr %f2,%f0 107 BR L2 108 atanIsZero: 109 FMOVD F0, ret+8(FP) 110 RET 111
