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Unified Diff: fusl/src/math/tanhf.c

Issue 1573973002: Add a "fork" of musl as //fusl. (Closed) Base URL: https://github.com/domokit/mojo.git@master
Patch Set: Created 4 years, 11 months ago
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Index: fusl/src/math/tanhf.c
diff --git a/fusl/src/math/tanhf.c b/fusl/src/math/tanhf.c
new file mode 100644
index 0000000000000000000000000000000000000000..10636fbd7be6c21d1c58326eba2bf7179b0dea8f
--- /dev/null
+++ b/fusl/src/math/tanhf.c
@@ -0,0 +1,39 @@
+#include "libm.h"
+
+float tanhf(float x)
+{
+ union {float f; uint32_t i;} u = {.f = x};
+ uint32_t w;
+ int sign;
+ float t;
+
+ /* x = |x| */
+ sign = u.i >> 31;
+ u.i &= 0x7fffffff;
+ x = u.f;
+ w = u.i;
+
+ if (w > 0x3f0c9f54) {
+ /* |x| > log(3)/2 ~= 0.5493 or nan */
+ if (w > 0x41200000) {
+ /* |x| > 10 */
+ t = 1 + 0/x;
+ } else {
+ t = expm1f(2*x);
+ t = 1 - 2/(t+2);
+ }
+ } else if (w > 0x3e82c578) {
+ /* |x| > log(5/3)/2 ~= 0.2554 */
+ t = expm1f(2*x);
+ t = t/(t+2);
+ } else if (w >= 0x00800000) {
+ /* |x| >= 0x1p-126 */
+ t = expm1f(-2*x);
+ t = -t/(t+2);
+ } else {
+ /* |x| is subnormal */
+ FORCE_EVAL(x*x);
+ t = x;
+ }
+ return sign ? -t : t;
+}
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