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Per IEEE754r, pow(1, y) is 1 even if y is NaN, and pow(-1, +-Inf) is 1.

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MFC after:	2 weeks
This commit is contained in:
David Schultz 2011-10-21 06:26:07 +00:00
parent 741ae1d017
commit cd24d79843
2 changed files with 8 additions and 2 deletions
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5
lib/msun/src/e_pow.c
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@ -109,6 +109,9 @@ __ieee754_pow(double x, double y)
/* y==zero: x**0 = 1 */
if((iy|ly)==0) return one;
/* x==1: 1**y = 1, even if y is NaN */
if (hx==0x3ff00000 && lx == 0) return one;
/* y!=zero: result is NaN if either arg is NaN */
if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0)))
@ -138,7 +141,7 @@ __ieee754_pow(double x, double y)
if(ly==0) {
if (iy==0x7ff00000) { /* y is +-inf */
if(((ix-0x3ff00000)|lx)==0)
return y - y; /* inf**+-1 is NaN */
return one; /* (-1)**+-inf is NaN */
else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */
return (hy>=0)? y: zero;
else /* (|x|<1)**-,+inf = inf,0 */

5
lib/msun/src/e_powf.c
View File

@ -67,6 +67,9 @@ __ieee754_powf(float x, float y)
/* y==zero: x**0 = 1 */
if(iy==0) return one;
/* x==1: 1**y = 1, even if y is NaN */
if (hx==0x3f800000) return one;
/* y!=zero: result is NaN if either arg is NaN */
if(ix > 0x7f800000 ||
iy > 0x7f800000)
@ -90,7 +93,7 @@ __ieee754_powf(float x, float y)
/* special value of y */
if (iy==0x7f800000) { /* y is +-inf */
if (ix==0x3f800000)
return y - y; /* inf**+-1 is NaN */
return one; /* (-1)**+-inf is NaN */
else if (ix > 0x3f800000)/* (|x|>1)**+-inf = inf,0 */
return (hy>=0)? y: zero;
else /* (|x|<1)**-,+inf = inf,0 */