github.com/c9s/go@v0.0.0-20180120015821-984e81f64e0c/src/math/tan_s390x.s (about)

     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