Index: fusl/src/math/exp10.c |
diff --git a/fusl/src/math/exp10.c b/fusl/src/math/exp10.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..9f5e3c2c51ea4afae2c62c10c6a392870cada366 |
--- /dev/null |
+++ b/fusl/src/math/exp10.c |
@@ -0,0 +1,25 @@ |
+#define _GNU_SOURCE |
+#include <math.h> |
+#include <stdint.h> |
+#include "libc.h" |
+ |
+double exp10(double x) |
+{ |
+ static const double p10[] = { |
+ 1e-15, 1e-14, 1e-13, 1e-12, 1e-11, 1e-10, |
+ 1e-9, 1e-8, 1e-7, 1e-6, 1e-5, 1e-4, 1e-3, 1e-2, 1e-1, |
+ 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, |
+ 1e10, 1e11, 1e12, 1e13, 1e14, 1e15 |
+ }; |
+ double n, y = modf(x, &n); |
+ union {double f; uint64_t i;} u = {n}; |
+ /* fabs(n) < 16 without raising invalid on nan */ |
+ if ((u.i>>52 & 0x7ff) < 0x3ff+4) { |
+ if (!y) return p10[(int)n+15]; |
+ y = exp2(3.32192809488736234787031942948939 * y); |
+ return y * p10[(int)n+15]; |
+ } |
+ return pow(10.0, x); |
+} |
+ |
+weak_alias(exp10, pow10); |