usr: libc: Add math.h + musl math impl portexpt

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/lib/libc/src/musl-math/hypotf.c b/lib/libc/src/musl-math/hypotf.c
new file mode 100644
index 0000000..2fc214b
--- /dev/null
+++ b/lib/libc/src/musl-math/hypotf.c
@@ -0,0 +1,35 @@
+#include <math.h>
+#include <stdint.h>
+
+float hypotf(float x, float y)
+{
+	union {float f; uint32_t i;} ux = {x}, uy = {y}, ut;
+	float_t z;
+
+	ux.i &= -1U>>1;
+	uy.i &= -1U>>1;
+	if (ux.i < uy.i) {
+		ut = ux;
+		ux = uy;
+		uy = ut;
+	}
+
+	x = ux.f;
+	y = uy.f;
+	if (uy.i == 0xff<<23)
+		return y;
+	if (ux.i >= 0xff<<23 || uy.i == 0 || ux.i - uy.i >= 25<<23)
+		return x + y;
+
+	z = 1;
+	if (ux.i >= (0x7f+60)<<23) {
+		z = 0x1p90f;
+		x *= 0x1p-90f;
+		y *= 0x1p-90f;
+	} else if (uy.i < (0x7f-60)<<23) {
+		z = 0x1p-90f;
+		x *= 0x1p90f;
+		y *= 0x1p90f;
+	}
+	return z*sqrtf((double)x*x + (double)y*y);
+}