Mercurial > sdl-ios-xcode

diff src/video/e_log.h @ 1662:782fd950bd46 SDL-1.3

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Revamp of the video system in progress - adding support for multiple displays, multiple windows, and a full video mode selection API. WARNING: None of the video drivers have been updated for the new API yet! The API is still under design and very fluid. The code is now run through a consistent indent format: indent -i4 -nut -nsc -br -ce The headers are being converted to automatically generate doxygen documentation.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 28 May 2006 13:04:16 +0000
parents 450721ad5436
children 4da1ee79c9af
line wrap: on
line diff
--- a/src/video/e_log.h	Sun May 21 17:27:13 2006 +0000
+++ b/src/video/e_log.h	Sun May 28 13:04:16 2006 +0000
@@ -73,68 +73,89 @@
 #else
 static double
 #endif
-ln2_hi  =  6.93147180369123816490e-01,	/* 3fe62e42 fee00000 */
-ln2_lo  =  1.90821492927058770002e-10,	/* 3dea39ef 35793c76 */
-Lg1 = 6.666666666666735130e-01,  /* 3FE55555 55555593 */
-Lg2 = 3.999999999940941908e-01,  /* 3FD99999 9997FA04 */
-Lg3 = 2.857142874366239149e-01,  /* 3FD24924 94229359 */
-Lg4 = 2.222219843214978396e-01,  /* 3FCC71C5 1D8E78AF */
-Lg5 = 1.818357216161805012e-01,  /* 3FC74664 96CB03DE */
-Lg6 = 1.531383769920937332e-01,  /* 3FC39A09 D078C69F */
-Lg7 = 1.479819860511658591e-01;  /* 3FC2F112 DF3E5244 */
+  ln2_hi = 6.93147180369123816490e-01,  /* 3fe62e42 fee00000 */
+    ln2_lo = 1.90821492927058770002e-10,        /* 3dea39ef 35793c76 */
+    Lg1 = 6.666666666666735130e-01,     /* 3FE55555 55555593 */
+    Lg2 = 3.999999999940941908e-01,     /* 3FD99999 9997FA04 */
+    Lg3 = 2.857142874366239149e-01,     /* 3FD24924 94229359 */
+    Lg4 = 2.222219843214978396e-01,     /* 3FCC71C5 1D8E78AF */
+    Lg5 = 1.818357216161805012e-01,     /* 3FC74664 96CB03DE */
+    Lg6 = 1.531383769920937332e-01,     /* 3FC39A09 D078C69F */
+    Lg7 = 1.479819860511658591e-01;     /* 3FC2F112 DF3E5244 */
 
 #ifdef __STDC__
-	double __ieee754_log(double x)
+double
+__ieee754_log (double x)
 #else
-	double __ieee754_log(x)
-	double x;
+double
+__ieee754_log (x)
+     double x;
 #endif
 {
-	double hfsq,f,s,z,R,w,t1,t2,dk;
-	int32_t k,hx,i,j;
-	u_int32_t lx;
+    double hfsq, f, s, z, R, w, t1, t2, dk;
+    int32_t k, hx, i, j;
+    u_int32_t lx;
 
-	EXTRACT_WORDS(hx,lx,x);
+    EXTRACT_WORDS (hx, lx, x);
 
-	k=0;
-	if (hx < 0x00100000) {			/* x < 2**-1022  */
-	    if (((hx&0x7fffffff)|lx)==0)
-		return -two54/zero;		/* log(+-0)=-inf */
-	    if (hx<0) return (x-x)/zero;	/* log(-#) = NaN */
-	    k -= 54; x *= two54; /* subnormal number, scale up x */
-	    GET_HIGH_WORD(hx,x);
-	}
-	if (hx >= 0x7ff00000) return x+x;
-	k += (hx>>20)-1023;
-	hx &= 0x000fffff;
-	i = (hx+0x95f64)&0x100000;
-	SET_HIGH_WORD(x,hx|(i^0x3ff00000));	/* normalize x or x/2 */
-	k += (i>>20);
-	f = x-1.0;
-	if((0x000fffff&(2+hx))<3) {	/* |f| < 2**-20 */
-	    if(f==zero) {if(k==0) return zero;  else {dk=(double)k;
-				 return dk*ln2_hi+dk*ln2_lo;}
-	    }
-	    R = f*f*(0.5-0.33333333333333333*f);
-	    if(k==0) return f-R; else {dk=(double)k;
-	    	     return dk*ln2_hi-((R-dk*ln2_lo)-f);}
-	}
- 	s = f/(2.0+f);
-	dk = (double)k;
-	z = s*s;
-	i = hx-0x6147a;
-	w = z*z;
-	j = 0x6b851-hx;
-	t1= w*(Lg2+w*(Lg4+w*Lg6));
-	t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7)));
-	i |= j;
-	R = t2+t1;
-	if(i>0) {
-	    hfsq=0.5*f*f;
-	    if(k==0) return f-(hfsq-s*(hfsq+R)); else
-		     return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f);
-	} else {
-	    if(k==0) return f-s*(f-R); else
-		     return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f);
-	}
+    k = 0;
+    if (hx < 0x00100000) {      /* x < 2**-1022  */
+        if (((hx & 0x7fffffff) | lx) == 0)
+            return -two54 / zero;       /* log(+-0)=-inf */
+        if (hx < 0)
+            return (x - x) / zero;      /* log(-#) = NaN */
+        k -= 54;
+        x *= two54;             /* subnormal number, scale up x */
+        GET_HIGH_WORD (hx, x);
+    }
+    if (hx >= 0x7ff00000)
+        return x + x;
+    k += (hx >> 20) - 1023;
+    hx &= 0x000fffff;
+    i = (hx + 0x95f64) & 0x100000;
+    SET_HIGH_WORD (x, hx | (i ^ 0x3ff00000));   /* normalize x or x/2 */
+    k += (i >> 20);
+    f = x - 1.0;
+    if ((0x000fffff & (2 + hx)) < 3) {  /* |f| < 2**-20 */
+        if (f == zero) {
+            if (k == 0)
+                return zero;
+            else {
+                dk = (double) k;
+                return dk * ln2_hi + dk * ln2_lo;
+            }
+        }
+        R = f * f * (0.5 - 0.33333333333333333 * f);
+        if (k == 0)
+            return f - R;
+        else {
+            dk = (double) k;
+            return dk * ln2_hi - ((R - dk * ln2_lo) - f);
+        }
+    }
+    s = f / (2.0 + f);
+    dk = (double) k;
+    z = s * s;
+    i = hx - 0x6147a;
+    w = z * z;
+    j = 0x6b851 - hx;
+    t1 = w * (Lg2 + w * (Lg4 + w * Lg6));
+    t2 = z * (Lg1 + w * (Lg3 + w * (Lg5 + w * Lg7)));
+    i |= j;
+    R = t2 + t1;
+    if (i > 0) {
+        hfsq = 0.5 * f * f;
+        if (k == 0)
+            return f - (hfsq - s * (hfsq + R));
+        else
+            return dk * ln2_hi - ((hfsq - (s * (hfsq + R) + dk * ln2_lo)) -
+                                  f);
+    } else {
+        if (k == 0)
+            return f - s * (f - R);
+        else
+            return dk * ln2_hi - ((s * (f - R) - dk * ln2_lo) - f);
+    }
 }
+
+/* vi: set ts=4 sw=4 expandtab: */