atan2f.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include "libm.h"
extern int __swapRP(int);
#endif
/*
* For i = 0, ..., 192, let x[i] be the double precision number whose
* high order 32 bits are 0x3f900000 + (i << 16) and whose low order
* 32 bits are zero. Then TBL[i] := atan(x[i]) to double precision.
*/
static const double TBL[] = {
1.56237286204768313e-02,
1.66000375562312640e-02,
1.75763148444955872e-02,
1.85525586258889763e-02,
1.95287670414137082e-02,
2.05049382324763683e-02,
2.14810703409090559e-02,
2.24571615089905717e-02,
2.34332098794675855e-02,
2.44092135955758099e-02,
2.53851708010611396e-02,
2.63610796402007873e-02,
2.73369382578244127e-02,
2.83127447993351995e-02,
2.92884974107309737e-02,
3.02641942386252458e-02,
3.12398334302682774e-02,
3.31909314971115949e-02,
3.51417768027967800e-02,
3.70923545503918164e-02,
3.90426499551669928e-02,
4.09926482452637811e-02,
4.29423346623621707e-02,
4.48916944623464972e-02,
4.68407129159696539e-02,
4.87893753095156174e-02,
5.07376669454602178e-02,
5.26855731431300420e-02,
5.46330792393594777e-02,
5.65801705891457105e-02,
5.85268325663017702e-02,
6.04730505641073168e-02,
6.24188099959573500e-02,
6.63088949198234884e-02,
7.01969710718705203e-02,
7.40829225490337306e-02,
7.79666338315423008e-02,
8.18479898030765457e-02,
8.57268757707448092e-02,
8.96031774848717461e-02,
9.34767811585894698e-02,
9.73475734872236709e-02,
1.01215441667466668e-01,
1.05080273416329528e-01,
1.08941956989865793e-01,
1.12800381201659389e-01,
1.16655435441069349e-01,
1.20507009691224562e-01,
1.24354994546761438e-01,
1.32039761614638762e-01,
1.39708874289163648e-01,
1.47361481088651630e-01,
1.54996741923940973e-01,
1.62613828597948568e-01,
1.70211925285474408e-01,
1.77790228992676075e-01,
1.85347949995694761e-01,
1.92884312257974672e-01,
2.00398553825878512e-01,
2.07889927202262986e-01,
2.15357699697738048e-01,
2.22801153759394521e-01,
2.30219587276843718e-01,
2.37612313865471242e-01,
2.44978663126864143e-01,
2.59629629408257512e-01,
2.74167451119658789e-01,
2.88587361894077410e-01,
3.02884868374971417e-01,
3.17055753209147029e-01,
3.31096076704132103e-01,
3.45002177207105132e-01,
3.58770670270572245e-01,
3.72398446676754202e-01,
3.85882669398073752e-01,
3.99220769575252543e-01,
4.12410441597387323e-01,
4.25449637370042266e-01,
4.38336559857957830e-01,
4.51069655988523499e-01,
4.63647609000806094e-01,
4.88333951056405535e-01,
5.12389460310737732e-01,
5.35811237960463704e-01,
5.58599315343562441e-01,
5.80756353567670414e-01,
6.02287346134964152e-01,
6.23199329934065904e-01,
6.43501108793284371e-01,
6.63202992706093286e-01,
6.82316554874748071e-01,
7.00854407884450192e-01,
7.18829999621624527e-01,
7.36257428981428097e-01,
7.53151280962194414e-01,
7.69526480405658297e-01,
7.85398163397448279e-01,
8.15691923316223422e-01,
8.44153986113171051e-01,
8.70903457075652976e-01,
8.96055384571343927e-01,
9.19719605350416858e-01,
9.42000040379463610e-01,
9.62994330680936206e-01,
9.82793723247329054e-01,
1.00148313569423464e+00,
1.01914134426634972e+00,
1.03584125300880014e+00,
1.05165021254837376e+00,
1.06663036531574362e+00,
1.08083900054116833e+00,
1.09432890732118993e+00,
1.10714871779409041e+00,
1.13095374397916038e+00,
1.15257199721566761e+00,
1.17227388112847630e+00,
1.19028994968253166e+00,
1.20681737028525249e+00,
1.22202532321098967e+00,
1.23605948947808186e+00,
1.24904577239825443e+00,
1.26109338225244039e+00,
1.27229739520871732e+00,
1.28274087974427076e+00,
1.29249666778978534e+00,
1.30162883400919616e+00,
1.31019393504755555e+00,
1.31824205101683711e+00,
1.32581766366803255e+00,
1.33970565959899957e+00,
1.35212738092095464e+00,
1.36330010035969384e+00,
1.37340076694501589e+00,
1.38257482149012589e+00,
1.39094282700241845e+00,
1.39860551227195762e+00,
1.40564764938026987e+00,
1.41214106460849531e+00,
1.41814699839963154e+00,
1.42371797140649403e+00,
1.42889927219073276e+00,
1.43373015248470903e+00,
1.43824479449822262e+00,
1.44247309910910193e+00,
1.44644133224813509e+00,
1.45368758222803240e+00,
1.46013910562100091e+00,
1.46591938806466282e+00,
1.47112767430373470e+00,
1.47584462045214027e+00,
1.48013643959415142e+00,
1.48405798811891154e+00,
1.48765509490645531e+00,
1.49096634108265924e+00,
1.49402443552511865e+00,
1.49685728913695626e+00,
1.49948886200960629e+00,
1.50193983749385196e+00,
1.50422816301907281e+00,
1.50636948736934317e+00,
1.50837751679893928e+00,
1.51204050407917401e+00,
1.51529782154917969e+00,
1.51821326518395483e+00,
1.52083793107295384e+00,
1.52321322351791322e+00,
1.52537304737331958e+00,
1.52734543140336587e+00,
1.52915374769630819e+00,
1.53081763967160667e+00,
1.53235373677370856e+00,
1.53377621092096650e+00,
1.53509721411557254e+00,
1.53632722579538861e+00,
1.53747533091664934e+00,
1.53854944435964280e+00,
1.53955649336462841e+00,
1.54139303859089161e+00,
1.54302569020147562e+00,
1.54448660954197448e+00,
1.54580153317597646e+00,
1.54699130060982659e+00,
1.54807296595325550e+00,
1.54906061995310385e+00,
1.54996600675867957e+00,
1.55079899282174605e+00,
1.55156792769518947e+00,
1.55227992472688747e+00,
1.55294108165534417e+00,
1.55355665560036682e+00,
1.55413120308095598e+00,
1.55466869295126031e+00,
1.55517259817441977e+00,
};
static const double
pio4 = 7.8539816339744827900e-01,
pio2 = 1.5707963267948965580e+00,
negpi = -3.1415926535897931160e+00,
q1 = -3.3333333333296428046e-01,
q2 = 1.9999999186853752618e-01,
zero = 0.0;
static const float two24 = 16777216.0;
float
{
double a, t, s, dbase;
float x, y, base;
int rp;
#endif
sign = 0;
x = fy;
y = fx;
i = hx;
hy = i;
if (iy < 0) {
x = -x;
sign = 1;
}
if (ix < 0) {
y = -y;
a = pio2;
} else {
a = -pio2;
}
} else {
y = fy;
x = fx;
if (iy < 0) {
y = -y;
sign = 1;
}
if (ix < 0) {
x = -x;
a = negpi;
} else {
a = zero;
}
}
if (hx >= 0x7f800000) {
return (x * y);
else if (hy >= 0x7f800000)
a += pio4;
} else if ((int)a == 0) {
a = (double)y / x;
}
return ((float)((sign)? -a : a));
}
if (hy < 0x00800000) {
if (hy == 0)
return ((float)((sign)? -a : a));
/* scale subnormal y */
y *= two24;
x *= two24;
hy = *(int *)&y;
hx = *(int *)&x;
}
#endif
if (k >= 0x3c800000) { /* |y/x| >= 1/64 */
*(int *)&base = k;
k = (k - 0x3c800000) >> 19;
a += TBL[k];
} else {
/*
* For some reason this is faster on USIII than just
* doing t = y/x in this case.
*/
*(int *)&base = 0;
}
s = t * t;
if (rp != fp_extended)
#endif
return ((float)((sign)? -a : a));
}