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Added atan2 implementation from uClibc

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slouken committed Aug 29, 2010
1 parent 56fadf2 commit 210300e31143400856c4075803085a9127605c51
Showing with 128 additions and 1 deletion.
  1. +1 −1 configure.in
  2. +1 −0 include/SDL_config.h.in
  3. +6 −0 include/SDL_stdinc.h
  4. +116 −0 src/libm/e_atan2.c
  5. +4 −0 src/libm/math.h
@@ -235,7 +235,7 @@ if test x$enable_libc = xyes; then
AC_CHECK_FUNCS(malloc calloc realloc free getenv setenv putenv unsetenv qsort abs bcopy memset memcpy memmove strlen strlcpy strlcat strdup _strrev _strupr _strlwr strchr strrchr strstr itoa _ltoa _uitoa _ultoa strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp sscanf snprintf vsnprintf sigaction setjmp nanosleep sysconf sysctlbyname)

AC_CHECK_LIB(m, pow, [LIBS="$LIBS -lm"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"])
AC_CHECK_FUNCS(ceil copysign cos cosf fabs floor log pow scalbn sin sinf sqrt)
AC_CHECK_FUNCS(atan2 ceil copysign cos cosf fabs floor log pow scalbn sin sinf sqrt)

AC_CHECK_LIB(iconv, libiconv_open, [LIBS="$LIBS -liconv"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -liconv"])
AC_CHECK_FUNCS(iconv)
@@ -136,6 +136,7 @@
#undef HAVE_SNPRINTF
#undef HAVE_VSNPRINTF
#undef HAVE_M_PI
#undef HAVE_ATAN2
#undef HAVE_CEIL
#undef HAVE_COPYSIGN
#undef HAVE_COS
@@ -694,6 +694,12 @@ extern DECLSPEC int SDLCALL SDL_vsnprintf(char *text, size_t maxlen,
#define M_PI 3.14159265358979323846264338327950288 /* pi */
#endif

#ifdef HAVE_ATAN2
#define SDL_atan2 atan2
#else
extern DECLSPEC double SDLCALL SDL_atan2(double y, double x);
#endif

#ifdef HAVE_CEIL
#define SDL_ceil ceil
#else
@@ -0,0 +1,116 @@
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/

/* __ieee754_atan2(y,x)
* Method :
* 1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
* 2. Reduce x to positive by (if x and y are unexceptional):
* ARG (x+iy) = arctan(y/x) ... if x > 0,
* ARG (x+iy) = pi - arctan[y/(-x)] ... if x < 0,
*
* Special cases:
*
* ATAN2((anything), NaN ) is NaN;
* ATAN2(NAN , (anything) ) is NaN;
* ATAN2(+-0, +(anything but NaN)) is +-0 ;
* ATAN2(+-0, -(anything but NaN)) is +-pi ;
* ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2;
* ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
* ATAN2(+-(anything but INF and NaN), -INF) is +-pi;
* ATAN2(+-INF,+INF ) is +-pi/4 ;
* ATAN2(+-INF,-INF ) is +-3pi/4;
* ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2;
*
* Constants:
* The hexadecimal values are the intended ones for the following
* constants. The decimal values may be used, provided that the
* compiler will convert from decimal to binary accurately enough
* to produce the hexadecimal values shown.
*/

#include "math.h"
#include "math_private.h"

static const double
tiny = 1.0e-300,
zero = 0.0,
pi_o_4 = 7.8539816339744827900E-01, /* 0x3FE921FB, 0x54442D18 */
pi_o_2 = 1.5707963267948965580E+00, /* 0x3FF921FB, 0x54442D18 */
pi = 3.1415926535897931160E+00, /* 0x400921FB, 0x54442D18 */
pi_lo = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */

double attribute_hidden __ieee754_atan2(double y, double x)
{
double z;
int32_t k,m,hx,hy,ix,iy;
u_int32_t lx,ly;

EXTRACT_WORDS(hx,lx,x);
ix = hx&0x7fffffff;
EXTRACT_WORDS(hy,ly,y);
iy = hy&0x7fffffff;
if(((ix|((lx|-lx)>>31))>0x7ff00000)||
((iy|((ly|-ly)>>31))>0x7ff00000)) /* x or y is NaN */
return x+y;
if(((hx-0x3ff00000)|lx)==0) return atan(y); /* x=1.0 */
m = ((hy>>31)&1)|((hx>>30)&2); /* 2*sign(x)+sign(y) */

/* when y = 0 */
if((iy|ly)==0) {
switch(m) {
case 0:
case 1: return y; /* atan(+-0,+anything)=+-0 */
case 2: return pi+tiny;/* atan(+0,-anything) = pi */
case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
}
}
/* when x = 0 */
if((ix|lx)==0) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;

/* when x is INF */
if(ix==0x7ff00000) {
if(iy==0x7ff00000) {
switch(m) {
case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */
case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
case 2: return 3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
case 3: return -3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/
}
} else {
switch(m) {
case 0: return zero ; /* atan(+...,+INF) */
case 1: return -zero ; /* atan(-...,+INF) */
case 2: return pi+tiny ; /* atan(+...,-INF) */
case 3: return -pi-tiny ; /* atan(-...,-INF) */
}
}
}
/* when y is INF */
if(iy==0x7ff00000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;

/* compute y/x */
k = (iy-ix)>>20;
if(k > 60) z=pi_o_2+0.5*pi_lo; /* |y/x| > 2**60 */
else if(hx<0&&k<-60) z=0.0; /* |y|/x < -2**60 */
else z=atan(fabs(y/x)); /* safe to do y/x */
switch (m) {
case 0: return z ; /* atan(+,+) */
case 1: {
u_int32_t zh;
GET_HIGH_WORD(zh,z);
SET_HIGH_WORD(z,zh ^ 0x80000000);
}
return z ; /* atan(-,+) */
case 2: return pi-(z-pi_lo);/* atan(+,-) */
default: /* case 3 */
return (z-pi_lo)-pi;/* atan(-,-) */
}
}
@@ -24,6 +24,10 @@

/* Math routines from uClibc: http://www.uclibc.org */

#ifndef HAVE_ATAN2
#define __ieee754_atan2 SDL_atan2
#endif

#ifdef HAVE_COPYSIGN
#define copysign SDL_uclibc_copysign
#else

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