SDL_exp

CMakeLists.txt

@@ -650,7 +650,7 @@ if(LIBC)
             _ultoa strtol strtoul strtoll strtod atoi atof strcmp strncmp
             _stricmp _strnicmp sscanf
             acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf
-            copysign copysignf cos cosf fabs fabsf floor floorf fmod fmodf
+            copysign copysignf cos cosf exp expf fabs fabsf floor floorf fmod fmodf
             log logf log10 log10f pow powf scalbn scalbnf sin sinf sqrt sqrtf tan tanf)
       string(TOUPPER ${_FN} _UPPER)
       set(HAVE_${_UPPER} 1)

VisualC/SDL/SDL.vcxproj

@@ -418,6 +418,7 @@
     <ClCompile Include="..\..\src\joystick\windows\SDL_windowsjoystick.c" />
     <ClCompile Include="..\..\src\joystick\windows\SDL_xinputjoystick.c" />
     <ClCompile Include="..\..\src\libm\e_atan2.c" />
+    <ClCompile Include="..\..\src\libm\e_exp.c" />
     <ClCompile Include="..\..\src\libm\e_fmod.c" />
     <ClCompile Include="..\..\src\libm\e_log.c" />
     <ClCompile Include="..\..\src\libm\e_log10.c" />

VisualC/SDL/SDL.vcxproj.filters

@@ -316,6 +316,7 @@
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="..\..\src\libm\e_atan2.c" />
+    <ClCompile Include="..\..\src\libm\e_exp.c" />
     <ClCompile Include="..\..\src\libm\e_log.c" />
     <ClCompile Include="..\..\src\libm\e_log10.c" />
     <ClCompile Include="..\..\src\libm\e_pow.c" />

configure

@@ -16699,7 +16699,7 @@ if test "x$ac_cv_lib_m_pow" = xyes; then :
   LIBS="$LIBS -lm"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"
 fi
 
-    for ac_func in acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf copysign copysignf cos cosf fabs fabsf floor floorf fmod fmodf log logf log10 log10f pow powf scalbn scalbnf sin sinf sqrt sqrtf tan tanf
+    for ac_func in acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf copysign copysignf cos cosf exp expf fabs fabsf floor floorf fmod fmodf log logf log10 log10f pow powf scalbn scalbnf sin sinf sqrt sqrtf tan tanf
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

configure.in

@@ -278,7 +278,7 @@ if test x$enable_libc = xyes; then
     AC_CHECK_FUNCS(malloc calloc realloc free getenv setenv putenv unsetenv qsort abs bcopy memset memcpy memmove wcslen wcscmp strlen strlcpy strlcat _strrev _strupr _strlwr strchr strrchr strstr itoa _ltoa _uitoa _ultoa strtol strtoul _i64toa _ui64toa strtoll strtoull atoi atof strcmp strncmp _stricmp strcasecmp _strnicmp strncasecmp vsscanf vsnprintf fopen64 fseeko fseeko64 sigaction setjmp nanosleep sysconf sysctlbyname getauxval poll)
 
     AC_CHECK_LIB(m, pow, [LIBS="$LIBS -lm"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -lm"])
-    AC_CHECK_FUNCS(acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf copysign copysignf cos cosf fabs fabsf floor floorf fmod fmodf log logf log10 log10f pow powf scalbn scalbnf sin sinf sqrt sqrtf tan tanf)
+    AC_CHECK_FUNCS(acos acosf asin asinf atan atanf atan2 atan2f ceil ceilf copysign copysignf cos cosf exp expf fabs fabsf floor floorf fmod fmodf log logf log10 log10f pow powf scalbn scalbnf sin sinf sqrt sqrtf tan tanf)
 
     AC_CHECK_LIB(iconv, iconv_open, [LIBS="$LIBS -liconv"; EXTRA_LDFLAGS="$EXTRA_LDFLAGS -liconv"])
     AC_CHECK_FUNCS(iconv)

include/SDL_config.h.cmake

@@ -144,6 +144,8 @@
 #cmakedefine HAVE_COPYSIGNF 1
 #cmakedefine HAVE_COS 1
 #cmakedefine HAVE_COSF 1
+#cmakedefine HAVE_EXP 1
+#cmakedefine HAVE_EXPF 1
 #cmakedefine HAVE_FABS 1
 #cmakedefine HAVE_FABSF 1
 #cmakedefine HAVE_FLOOR 1

include/SDL_config.h.in

@@ -149,6 +149,8 @@
 #undef HAVE_COPYSIGNF
 #undef HAVE_COS
 #undef HAVE_COSF
+#undef HAVE_EXP
+#undef HAVE_EXPF
 #undef HAVE_FABS
 #undef HAVE_FABSF
 #undef HAVE_FLOOR

include/SDL_config_android.h

@@ -98,6 +98,8 @@
 #define HAVE_COPYSIGNF  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_iphoneos.h

@@ -99,6 +99,8 @@
 #define HAVE_COPYSIGNF  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_macosx.h

@@ -102,6 +102,8 @@
 #define HAVE_COPYSIGNF  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_pandora.h

@@ -90,6 +90,7 @@
 #define HAVE_COPYSIGN 1
 #define HAVE_COS 1
 #define HAVE_COSF 1
+#define HAVE_EXP 1
 #define HAVE_FABS 1
 #define HAVE_FLOOR 1
 #define HAVE_LOG 1

include/SDL_config_psp.h

@@ -97,6 +97,8 @@
 #define HAVE_COPYSIGNF  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_windows.h

@@ -139,6 +139,8 @@ typedef unsigned int uintptr_t;
 #define HAVE__COPYSIGN  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_winrt.h

@@ -155,6 +155,8 @@ typedef unsigned int uintptr_t;
 #define HAVE__COPYSIGN 1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_config_wiz.h

@@ -94,6 +94,8 @@
 #define HAVE_COPYSIGNF  1
 #define HAVE_COS    1
 #define HAVE_COSF   1
+#define HAVE_EXP    1
+#define HAVE_EXPF   1
 #define HAVE_FABS   1
 #define HAVE_FABSF  1
 #define HAVE_FLOOR  1

include/SDL_stdinc.h

@@ -513,6 +513,8 @@ extern DECLSPEC double SDLCALL SDL_copysign(double x, double y);
 extern DECLSPEC float SDLCALL SDL_copysignf(float x, float y);
 extern DECLSPEC double SDLCALL SDL_cos(double x);
 extern DECLSPEC float SDLCALL SDL_cosf(float x);
+extern DECLSPEC double SDLCALL SDL_exp(double x);
+extern DECLSPEC float SDLCALL SDL_expf(float x);
 extern DECLSPEC double SDLCALL SDL_fabs(double x);
 extern DECLSPEC float SDLCALL SDL_fabsf(float x);
 extern DECLSPEC double SDLCALL SDL_floor(double x);

src/dynapi/SDL_dynapi_overrides.h

@@ -675,3 +675,5 @@
 #define SDL_IsChromebook SDL_IsChromebook_REAL
 #define SDL_IsDeXMode SDL_IsDeXMode_REAL
 #define SDL_AndroidBackButton SDL_AndroidBackButton_REAL
+#define SDL_exp SDL_exp_REAL
+#define SDL_expf SDL_expf_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -719,3 +719,5 @@ SDL_DYNAPI_PROC(SDL_bool,SDL_IsDeXMode,(void),(),return)
 #ifdef __ANDROID__
 SDL_DYNAPI_PROC(void,SDL_AndroidBackButton,(void),(),return)
 #endif
+SDL_DYNAPI_PROC(double,SDL_exp,(double a),(a),return)
+SDL_DYNAPI_PROC(float,SDL_expf,(float a),(a),return)

src/libm/e_exp.c

@@ -0,0 +1,182 @@
+/*
+ * ====================================================
+ * 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_exp(x)
+ * Returns the exponential of x.
+ *
+ * Method
+ *   1. Argument reduction:
+ *      Reduce x to an r so that |r| <= 0.5*ln2 ~ 0.34658.
+ *	Given x, find r and integer k such that
+ *
+ *               x = k*ln2 + r,  |r| <= 0.5*ln2.
+ *
+ *      Here r will be represented as r = hi-lo for better
+ *	accuracy.
+ *
+ *   2. Approximation of exp(r) by a special rational function on
+ *	the interval [0,0.34658]:
+ *	Write
+ *	    R(r**2) = r*(exp(r)+1)/(exp(r)-1) = 2 + r*r/6 - r**4/360 + ...
+ *      We use a special Reme algorithm on [0,0.34658] to generate
+ * 	a polynomial of degree 5 to approximate R. The maximum error
+ *	of this polynomial approximation is bounded by 2**-59. In
+ *	other words,
+ *	    R(z) ~ 2.0 + P1*z + P2*z**2 + P3*z**3 + P4*z**4 + P5*z**5
+ *  	(where z=r*r, and the values of P1 to P5 are listed below)
+ *	and
+ *	    |                  5          |     -59
+ *	    | 2.0+P1*z+...+P5*z   -  R(z) | <= 2
+ *	    |                             |
+ *	The computation of exp(r) thus becomes
+ *                             2*r
+ *		exp(r) = 1 + -------
+ *		              R - r
+ *                                 r*R1(r)
+ *		       = 1 + r + ----------- (for better accuracy)
+ *		                  2 - R1(r)
+ *	where
+ *			         2       4             10
+ *		R1(r) = r - (P1*r  + P2*r  + ... + P5*r   ).
+ *
+ *   3. Scale back to obtain exp(x):
+ *	From step 1, we have
+ *	   exp(x) = 2^k * exp(r)
+ *
+ * Special cases:
+ *	exp(INF) is INF, exp(NaN) is NaN;
+ *	exp(-INF) is 0, and
+ *	for finite argument, only exp(0)=1 is exact.
+ *
+ * Accuracy:
+ *	according to an error analysis, the error is always less than
+ *	1 ulp (unit in the last place).
+ *
+ * Misc. info.
+ *	For IEEE double
+ *	    if x >  7.09782712893383973096e+02 then exp(x) overflow
+ *	    if x < -7.45133219101941108420e+02 then exp(x) underflow
+ *
+ * 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_libm.h"
+#include "math_private.h"
+
+static const double
+one	= 1.0,
+halF[2]	= {0.5,-0.5,},
+huge	= 1.0e+300,
+twom1000= 9.33263618503218878990e-302,     /* 2**-1000=0x01700000,0*/
+o_threshold=  7.09782712893383973096e+02,  /* 0x40862E42, 0xFEFA39EF */
+u_threshold= -7.45133219101941108420e+02,  /* 0xc0874910, 0xD52D3051 */
+ln2HI[2]   ={ 6.93147180369123816490e-01,  /* 0x3fe62e42, 0xfee00000 */
+	     -6.93147180369123816490e-01,},/* 0xbfe62e42, 0xfee00000 */
+ln2LO[2]   ={ 1.90821492927058770002e-10,  /* 0x3dea39ef, 0x35793c76 */
+	     -1.90821492927058770002e-10,},/* 0xbdea39ef, 0x35793c76 */
+invln2 =  1.44269504088896338700e+00, /* 0x3ff71547, 0x652b82fe */
+P1   =  1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */
+P2   = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */
+P3   =  6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */
+P4   = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */
+P5   =  4.13813679705723846039e-08; /* 0x3E663769, 0x72BEA4D0 */
+
+double __ieee754_exp(double x)	/* default IEEE double exp */
+{
+	double y;
+	double hi = 0.0;
+	double lo = 0.0;
+	double c;
+	double t;
+	int32_t k=0;
+	int32_t xsb;
+	u_int32_t hx;
+
+	GET_HIGH_WORD(hx,x);
+	xsb = (hx>>31)&1;		/* sign bit of x */
+	hx &= 0x7fffffff;		/* high word of |x| */
+
+    /* filter out non-finite argument */
+	if(hx >= 0x40862E42) {			/* if |x|>=709.78... */
+            if(hx>=0x7ff00000) {
+	        u_int32_t lx;
+		GET_LOW_WORD(lx,x);
+		if(((hx&0xfffff)|lx)!=0)
+		     return x+x; 		/* NaN */
+		else return (xsb==0)? x:0.0;	/* exp(+-inf)={inf,0} */
+	    }
+	    if(x > o_threshold) return huge*huge; /* overflow */
+	    if(x < u_threshold) return twom1000*twom1000; /* underflow */
+	}
+
+    /* argument reduction */
+	if(hx > 0x3fd62e42) {		/* if  |x| > 0.5 ln2 */
+	    if(hx < 0x3FF0A2B2) {	/* and |x| < 1.5 ln2 */
+		hi = x-ln2HI[xsb]; lo=ln2LO[xsb]; k = 1-xsb-xsb;
+	    } else {
+		k  = invln2*x+halF[xsb];
+		t  = k;
+		hi = x - t*ln2HI[0];	/* t*ln2HI is exact here */
+		lo = t*ln2LO[0];
+	    }
+	    x  = hi - lo;
+	}
+	else if(hx < 0x3e300000)  {	/* when |x|<2**-28 */
+	    if(huge+x>one) return one+x;/* trigger inexact */
+	}
+	else k = 0;
+
+    /* x is now in primary range */
+	t  = x*x;
+	c  = x - t*(P1+t*(P2+t*(P3+t*(P4+t*P5))));
+	if(k==0) 	return one-((x*c)/(c-2.0)-x);
+	else 		y = one-((lo-(x*c)/(2.0-c))-hi);
+	if(k >= -1021) {
+	    u_int32_t hy;
+	    GET_HIGH_WORD(hy,y);
+	    SET_HIGH_WORD(y,hy+(k<<20));	/* add k to y's exponent */
+	    return y;
+	} else {
+	    u_int32_t hy;
+	    GET_HIGH_WORD(hy,y);
+	    SET_HIGH_WORD(y,hy+((k+1000)<<20));	/* add k to y's exponent */
+	    return y*twom1000;
+	}
+}
+
+/*
+ * wrapper exp(x)
+ */
+#ifndef _IEEE_LIBM
+double exp(double x)
+{
+	static const double o_threshold =  7.09782712893383973096e+02; /* 0x40862E42, 0xFEFA39EF */
+	static const double u_threshold = -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */
+
+	double z = __ieee754_exp(x);
+	if (_LIB_VERSION == _IEEE_)
+		return z;
+	if (isfinite(x)) {
+		if (x > o_threshold)
+			return __kernel_standard(x, x, 6); /* exp overflow */
+		if (x < u_threshold)
+			return __kernel_standard(x, x, 7); /* exp underflow */
+	}
+	return z;
+}
+#else
+strong_alias(__ieee754_exp, exp)
+#endif
+libm_hidden_def(exp)

src/libm/math_libm.h

@@ -26,6 +26,7 @@ double SDL_uclibc_atan(double x);
 double SDL_uclibc_atan2(double y, double x);    
 double SDL_uclibc_copysign(double x, double y);       
 double SDL_uclibc_cos(double x);         
+double SDL_uclibc_exp(double x);
 double SDL_uclibc_fabs(double x);        
 double SDL_uclibc_floor(double x);
 double SDL_uclibc_fmod(double x, double y);

src/libm/math_private.h

@@ -35,6 +35,7 @@ typedef unsigned int u_int32_t;
 #define __ieee754_atan2 SDL_uclibc_atan2
 #define copysign        SDL_uclibc_copysign
 #define cos             SDL_uclibc_cos
+#define __ieee754_exp   SDL_uclibc_exp
 #define fabs            SDL_uclibc_fabs
 #define floor           SDL_uclibc_floor
 #define __ieee754_fmod  SDL_uclibc_fmod

src/stdlib/SDL_stdlib.c

@@ -200,6 +200,26 @@ SDL_cosf(float x)
 #endif
 }
 
+double
+SDL_exp(double x)
+{
+#if defined(HAVE_EXP)
+    return exp(x);
+#else
+    return SDL_uclibc_exp(x);
+#endif
+}
+
+float
+SDL_expf(float x)
+{
+#if defined(HAVE_EXPF)
+    return expf(x);
+#else
+    return (float)SDL_uclibc_exp((double)x);
+#endif
+}
+
 double
 SDL_fabs(double x)
 {