diff options
Diffstat (limited to 'mdk-stage1/dietlibc/libm/ipow.c')
-rw-r--r-- | mdk-stage1/dietlibc/libm/ipow.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/mdk-stage1/dietlibc/libm/ipow.c b/mdk-stage1/dietlibc/libm/ipow.c new file mode 100644 index 000000000..399986ea1 --- /dev/null +++ b/mdk-stage1/dietlibc/libm/ipow.c @@ -0,0 +1,29 @@ +#define _GNU_SOURCE +#include <math.h> +/* + * This is not standard, but often you only need such this function + * which is much shorter than the generic pow() function. + * + * double ipow ( double mant, int expo ); + */ + +double ipow ( double mant, int expo ) +{ + double ret = 1.; + unsigned int e = expo; /* Some attention is necessary for expo = 2^31 */ + + if ( (int)e < 0 ) { + e = -e; + mant = 1./mant; + } + + while (1) { + if ( e & 1 ) + ret *= mant; + if ( (e >>= 1) == 0 ) + break; + mant *= mant; + } + + return ret; +} |