add special cases for powers 3 and 4, in addition to 2

This commit is contained in:
Jeff Bezanson 2013-04-03 14:40:47 -04:00
parent 3c8738e642
commit c9cf16d2de
2 changed files with 16 additions and 6 deletions

View File

@ -150,10 +150,15 @@ __ieee754_pow(double x, double y)
if(iy==0x3ff00000) { /* y is +-1 */
if(hy<0) return one/x; else return x;
}
if(hy==0x40000000) return x*x; /* y is 2 */
if(hy==0x3fe00000) { /* y is 0.5 */
if(hy==0x40000000) return x*x; /* y is 2 */
if(hy==0x40080000) return x*x*x; /* y is 3 */
if(hy==0x40100000) { /* y is 4 */
u = x*x;
return u*u;
}
if(hy==0x3fe00000) { /* y is 0.5 */
if(hx>=0) /* x >= +0 */
return sqrt(x);
return sqrt(x);
}
}

View File

@ -102,10 +102,15 @@ __ieee754_powf(float x, float y)
if(iy==0x3f800000) { /* y is +-1 */
if(hy<0) return one/x; else return x;
}
if(hy==0x40000000) return x*x; /* y is 2 */
if(hy==0x3f000000) { /* y is 0.5 */
if(hy==0x40000000) return x*x; /* y is 2 */
if(hy==0x40400000) return x*x*x; /* y is 3 */
if(hy==0x40800000) { /* y is 4 */
u = x*x;
return u*u;
}
if(hy==0x3f000000) { /* y is 0.5 */
if(hx>=0) /* x >= +0 */
return __ieee754_sqrtf(x);
return __ieee754_sqrtf(x);
}
ax = fabsf(x);