e_atan2f.c revision 1dc9e472e19acfe6dc7f41e429236e7eef7ceda1
11dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* e_atan2f.c -- float version of e_atan2.c. 21dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 41dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 51dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Developed at SunPro, a Sun Microsystems, Inc. business. 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Permission to use, copy, modify, and distribute this 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * software is freely granted, provided that this notice 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is preserved. 131dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 141dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#ifndef lint 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic char rcsid[] = "$FreeBSD: src/lib/msun/src/e_atan2f.c,v 1.7 2004/06/02 17:09:05 bde Exp $"; 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math.h" 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math_private.h" 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic const float 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projecttiny = 1.0e-30, 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectzero = 0.0, 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectpi_o_4 = 7.8539818525e-01, /* 0x3f490fdb */ 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectpi_o_2 = 1.5707963705e+00, /* 0x3fc90fdb */ 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectpi = 3.1415927410e+00, /* 0x40490fdb */ 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectpi_lo = -8.7422776573e-08; /* 0xb3bbbd2e */ 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectfloat 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project__ieee754_atan2f(float y, float x) 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project float z; 351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int32_t k,m,hx,hy,ix,iy; 361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project GET_FLOAT_WORD(hx,x); 381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ix = hx&0x7fffffff; 391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project GET_FLOAT_WORD(hy,y); 401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project iy = hy&0x7fffffff; 411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if((ix>0x7f800000)|| 421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project (iy>0x7f800000)) /* x or y is NaN */ 431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return x+y; 441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(hx==0x3f800000) return atanf(y); /* x=1.0 */ 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project m = ((hy>>31)&1)|((hx>>30)&2); /* 2*sign(x)+sign(y) */ 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* when y = 0 */ 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(iy==0) { 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project switch(m) { 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 0: 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 1: return y; /* atan(+-0,+anything)=+-0 */ 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 2: return pi+tiny;/* atan(+0,-anything) = pi */ 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */ 541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* when x = 0 */ 571dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(ix==0) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny; 581dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 591dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* when x is INF */ 601dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(ix==0x7f800000) { 611dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(iy==0x7f800000) { 621dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project switch(m) { 631dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */ 641dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */ 651dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 2: return (float)3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/ 661dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 3: return (float)-3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/ 671dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 681dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } else { 691dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project switch(m) { 701dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 0: return zero ; /* atan(+...,+INF) */ 711dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 1: return -zero ; /* atan(-...,+INF) */ 721dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 2: return pi+tiny ; /* atan(+...,-INF) */ 731dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 3: return -pi-tiny ; /* atan(-...,-INF) */ 741dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 751dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 761dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 771dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* when y is INF */ 781dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(iy==0x7f800000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny; 791dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 801dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project /* compute y/x */ 811dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project k = (iy-ix)>>23; 821dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(k > 60) z=pi_o_2+(float)0.5*pi_lo; /* |y/x| > 2**60 */ 831dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else if(hx<0&&k<-60) z=0.0; /* |y|/x < -2**60 */ 841dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project else z=atanf(fabsf(y/x)); /* safe to do y/x */ 851dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project switch (m) { 861dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 0: return z ; /* atan(+,+) */ 871dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 1: { 881dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project u_int32_t zh; 891dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project GET_FLOAT_WORD(zh,z); 901dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project SET_FLOAT_WORD(z,zh ^ 0x80000000); 911dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 921dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return z ; /* atan(-,+) */ 931dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project case 2: return pi-(z-pi_lo);/* atan(+,-) */ 941dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project default: /* case 3 */ 951dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return (z-pi_lo)-pi;/* atan(-,-) */ 961dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 971dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 98