diff options
Diffstat (limited to 'lib/mlibc/options/ansi/musl-generic-math/fmodf.c')
-rw-r--r-- | lib/mlibc/options/ansi/musl-generic-math/fmodf.c | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/mlibc/options/ansi/musl-generic-math/fmodf.c b/lib/mlibc/options/ansi/musl-generic-math/fmodf.c new file mode 100644 index 0000000..ff58f93 --- /dev/null +++ b/lib/mlibc/options/ansi/musl-generic-math/fmodf.c @@ -0,0 +1,65 @@ +#include <math.h> +#include <stdint.h> + +float fmodf(float x, float y) +{ + union {float f; uint32_t i;} ux = {x}, uy = {y}; + int ex = ux.i>>23 & 0xff; + int ey = uy.i>>23 & 0xff; + uint32_t sx = ux.i & 0x80000000; + uint32_t i; + uint32_t uxi = ux.i; + + if (uy.i<<1 == 0 || isnan(y) || ex == 0xff) + return (x*y)/(x*y); + if (uxi<<1 <= uy.i<<1) { + if (uxi<<1 == uy.i<<1) + return 0*x; + return x; + } + + /* normalize x and y */ + if (!ex) { + for (i = uxi<<9; i>>31 == 0; ex--, i <<= 1); + uxi <<= -ex + 1; + } else { + uxi &= -1U >> 9; + uxi |= 1U << 23; + } + if (!ey) { + for (i = uy.i<<9; i>>31 == 0; ey--, i <<= 1); + uy.i <<= -ey + 1; + } else { + uy.i &= -1U >> 9; + uy.i |= 1U << 23; + } + + /* x mod y */ + for (; ex > ey; ex--) { + i = uxi - uy.i; + if (i >> 31 == 0) { + if (i == 0) + return 0*x; + uxi = i; + } + uxi <<= 1; + } + i = uxi - uy.i; + if (i >> 31 == 0) { + if (i == 0) + return 0*x; + uxi = i; + } + for (; uxi>>23 == 0; uxi <<= 1, ex--); + + /* scale result up */ + if (ex > 0) { + uxi -= 1U << 23; + uxi |= (uint32_t)ex << 23; + } else { + uxi >>= -ex + 1; + } + uxi |= sx; + ux.i = uxi; + return ux.f; +} |