// Copyright 2016 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 tanhrodataL18<>+0(SB)/8, $-1.0
DATA tanhrodataL18<>+8(SB)/8, $-2.0
DATA tanhrodataL18<>+16(SB)/8, $1.0
DATA tanhrodataL18<>+24(SB)/8, $2.0
DATA tanhrodataL18<>+32(SB)/8, $0.20000000000000011868E+01
DATA tanhrodataL18<>+40(SB)/8, $0.13333333333333341256E+01
DATA tanhrodataL18<>+48(SB)/8, $0.26666666663549111502E+00
DATA tanhrodataL18<>+56(SB)/8, $0.66666666658721844678E+00
DATA tanhrodataL18<>+64(SB)/8, $0.88890217768964374821E-01
DATA tanhrodataL18<>+72(SB)/8, $0.25397199429103821138E-01
DATA tanhrodataL18<>+80(SB)/8, $-.346573590279972643E+00
DATA tanhrodataL18<>+88(SB)/8, $20.E0
GLOBL tanhrodataL18<>+0(SB), RODATA, $96
// Constants
DATA tanhrlog2<>+0(SB)/8, $0x4007154760000000
GLOBL tanhrlog2<>+0(SB), RODATA, $8
DATA tanhxadd<>+0(SB)/8, $0xc2f0000100003ff0
GLOBL tanhxadd<>+0(SB), RODATA, $8
DATA tanhxmone<>+0(SB)/8, $-1.0
GLOBL tanhxmone<>+0(SB), RODATA, $8
DATA tanhxzero<>+0(SB)/8, $0
GLOBL tanhxzero<>+0(SB), RODATA, $8
// Polynomial coefficients
DATA tanhtab<>+0(SB)/8, $0.000000000000000000E+00
DATA tanhtab<>+8(SB)/8, $-.171540871271399150E-01
DATA tanhtab<>+16(SB)/8, $-.306597931864376363E-01
DATA tanhtab<>+24(SB)/8, $-.410200970469965021E-01
DATA tanhtab<>+32(SB)/8, $-.486343079978231466E-01
DATA tanhtab<>+40(SB)/8, $-.538226193725835820E-01
DATA tanhtab<>+48(SB)/8, $-.568439602538111520E-01
DATA tanhtab<>+56(SB)/8, $-.579091847395528847E-01
DATA tanhtab<>+64(SB)/8, $-.571909584179366341E-01
DATA tanhtab<>+72(SB)/8, $-.548312665987204407E-01
DATA tanhtab<>+80(SB)/8, $-.509471843643441085E-01
DATA tanhtab<>+88(SB)/8, $-.456353588448863359E-01
DATA tanhtab<>+96(SB)/8, $-.389755254243262365E-01
DATA tanhtab<>+104(SB)/8, $-.310332908285244231E-01
DATA tanhtab<>+112(SB)/8, $-.218623539150173528E-01
DATA tanhtab<>+120(SB)/8, $-.115062908917949451E-01
GLOBL tanhtab<>+0(SB), RODATA, $128
// Tanh returns the hyperbolic tangent of the argument.
//
// Special cases are:
// Tanh(±0) = ±0
// Tanh(±Inf) = ±1
// Tanh(NaN) = NaN
// The algorithm used is minimax polynomial approximation using a table of
// polynomial coefficients determined with a Remez exchange algorithm.
TEXT ·tanhAsm(SB),NOSPLIT,$0-16
FMOVD x+0(FP), F0
// special case Tanh(±0) = ±0
FMOVD $(0.0), F1
FCMPU F0, F1
BEQ tanhIsZero
MOVD $tanhrodataL18<>+0(SB), R5
LTDBR F0, F0
MOVD $0x4034000000000000, R1
BLTU L15
FMOVD F0, F1
L2:
MOVD $tanhxadd<>+0(SB), R2
FMOVD 0(R2), F2
MOVD tanhrlog2<>+0(SB), R2
LDGR R2, F4
WFMSDB V0, V4, V2, V4
MOVD $tanhtab<>+0(SB), R3
LGDR F4, R2
RISBGZ $57, $60, $3, R2, R4
WORD $0xED105058 //cdb %f1,.L19-.L18(%r5)
BYTE $0x00
BYTE $0x19
RISBGN $0, $15, $48, R2, R1
WORD $0x68543000 //ld %f5,0(%r4,%r3)
LDGR R1, F6
BLT L3
MOVD $tanhxzero<>+0(SB), R1
FMOVD 0(R1), F2
WFCHDBS V0, V2, V4
BEQ L9
WFCHDBS V2, V0, V2
BNE L1
MOVD $tanhxmone<>+0(SB), R1
FMOVD 0(R1), F0
FMOVD F0, ret+8(FP)
RET
L3:
FADD F4, F2
FMOVD tanhrodataL18<>+80(SB), F4
FMADD F4, F2, F0
FMOVD tanhrodataL18<>+72(SB), F1
WFMDB V0, V0, V3
FMOVD tanhrodataL18<>+64(SB), F2
WFMADB V0, V1, V2, V1
FMOVD tanhrodataL18<>+56(SB), F4
FMOVD tanhrodataL18<>+48(SB), F2
WFMADB V1, V3, V4, V1
FMOVD tanhrodataL18<>+40(SB), F4
WFMADB V3, V2, V4, V2
FMOVD tanhrodataL18<>+32(SB), F4
WORD $0xB9270022 //lhr %r2,%r2
WFMADB V3, V1, V4, V1
FMOVD tanhrodataL18<>+24(SB), F4
WFMADB V3, V2, V4, V3
WFMADB V0, V5, V0, V2
WFMADB V0, V1, V3, V0
WORD $0xA7183ECF //lhi %r1,16079
WFMADB V0, V2, V5, V2
FMUL F6, F2
MOVW R2, R10
MOVW R1, R11
CMPBLE R10, R11, L16
FMOVD F6, F0
WORD $0xED005010 //adb %f0,.L28-.L18(%r5)
BYTE $0x00
BYTE $0x1A
WORD $0xA7184330 //lhi %r1,17200
FADD F2, F0
MOVW R2, R10
MOVW R1, R11
CMPBGT R10, R11, L17
WORD $0xED605010 //sdb %f6,.L28-.L18(%r5)
BYTE $0x00
BYTE $0x1B
FADD F6, F2
WFDDB V0, V2, V0
FMOVD F0, ret+8(FP)
RET
L9:
FMOVD tanhrodataL18<>+16(SB), F0
L1:
FMOVD F0, ret+8(FP)
RET
L15:
FNEG F0, F1
BR L2
L16:
FADD F6, F2
FMOVD tanhrodataL18<>+8(SB), F0
FMADD F4, F2, F0
FMOVD tanhrodataL18<>+0(SB), F4
FNEG F0, F0
WFMADB V0, V2, V4, V0
FMOVD F0, ret+8(FP)
RET
L17:
WFDDB V0, V4, V0
FMOVD tanhrodataL18<>+16(SB), F2
WFSDB V0, V2, V0
FMOVD F0, ret+8(FP)
RET
tanhIsZero: //return ±0
FMOVD F0, ret+8(FP)
RET
