Index: fusl/src/math/remquo.c |
diff --git a/fusl/src/math/remquo.c b/fusl/src/math/remquo.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..59d5ad57e54dfc8399b3994c88faf3dc15b8c0d0 |
--- /dev/null |
+++ b/fusl/src/math/remquo.c |
@@ -0,0 +1,82 @@ |
+#include <math.h> |
+#include <stdint.h> |
+ |
+double remquo(double x, double y, int *quo) |
+{ |
+ union {double f; uint64_t i;} ux = {x}, uy = {y}; |
+ int ex = ux.i>>52 & 0x7ff; |
+ int ey = uy.i>>52 & 0x7ff; |
+ int sx = ux.i>>63; |
+ int sy = uy.i>>63; |
+ uint32_t q; |
+ uint64_t i; |
+ uint64_t uxi = ux.i; |
+ |
+ *quo = 0; |
+ if (uy.i<<1 == 0 || isnan(y) || ex == 0x7ff) |
+ return (x*y)/(x*y); |
+ if (ux.i<<1 == 0) |
+ return x; |
+ |
+ /* normalize x and y */ |
+ if (!ex) { |
+ for (i = uxi<<12; i>>63 == 0; ex--, i <<= 1); |
+ uxi <<= -ex + 1; |
+ } else { |
+ uxi &= -1ULL >> 12; |
+ uxi |= 1ULL << 52; |
+ } |
+ if (!ey) { |
+ for (i = uy.i<<12; i>>63 == 0; ey--, i <<= 1); |
+ uy.i <<= -ey + 1; |
+ } else { |
+ uy.i &= -1ULL >> 12; |
+ uy.i |= 1ULL << 52; |
+ } |
+ |
+ q = 0; |
+ if (ex < ey) { |
+ if (ex+1 == ey) |
+ goto end; |
+ return x; |
+ } |
+ |
+ /* x mod y */ |
+ for (; ex > ey; ex--) { |
+ i = uxi - uy.i; |
+ if (i >> 63 == 0) { |
+ uxi = i; |
+ q++; |
+ } |
+ uxi <<= 1; |
+ q <<= 1; |
+ } |
+ i = uxi - uy.i; |
+ if (i >> 63 == 0) { |
+ uxi = i; |
+ q++; |
+ } |
+ if (uxi == 0) |
+ ex = -60; |
+ else |
+ for (; uxi>>52 == 0; uxi <<= 1, ex--); |
+end: |
+ /* scale result and decide between |x| and |x|-|y| */ |
+ if (ex > 0) { |
+ uxi -= 1ULL << 52; |
+ uxi |= (uint64_t)ex << 52; |
+ } else { |
+ uxi >>= -ex + 1; |
+ } |
+ ux.i = uxi; |
+ x = ux.f; |
+ if (sy) |
+ y = -y; |
+ if (ex == ey || (ex+1 == ey && (2*x > y || (2*x == y && q%2)))) { |
+ x -= y; |
+ q++; |
+ } |
+ q &= 0x7fffffff; |
+ *quo = sx^sy ? -(int)q : (int)q; |
+ return sx ? -x : x; |
+} |