1 files changed, 64 insertions, 0 deletions
diff --git a/src/libultra_code_O2/cosf.c b/src/libultra_code_O2/cosf.c
new file mode 100644
index 000000000..56ef995c7
--- /dev/null
+++ b/src/libultra_code_O2/cosf.c
@@ -0,0 +1,64 @@
+#include "ultra64.h"
+#include "global.h"
+
+static const du P[] = {
+    { 0x3FF00000, 0x00000000 }, { 0xBFC55554, 0xBC83656D }, { 0x3F8110ED, 0x3804C2A0 },
+    { 0xBF29f6FF, 0xEEA56814 }, { 0x3EC5DBDF, 0x0E314BFE },
+};
+
+static const du rpi = { 0x3FD45F30, 0x6DC9C883 };
+
+static const du pihi = { 0x400921FB, 0x50000000 };
+
+static const du pilo = { 0x3E6110B4, 0x611A6263 };
+
+static const fu zero = { 0x00000000 };
+
+f32 cosf(f32 x) {
+    f32 absx;
+    f64 dx;
+    f64 xSq;
+    f64 polyApprox;
+    f64 dn;
+    s32 n;
+    f64 result;
+    s32 ix, xpt;
+
+    ix = *(s32*)&x;
+    xpt = (ix >> 22);
+    xpt &= 0x1FF;
+
+    if (xpt < 0x136) {
+
+        absx = (x > 0) ? x : -x;
+
+        dx = absx;
+
+        dn = dx * rpi.d + 0.5;
+        n = ROUND(dn);
+        dn = n;
+
+        dn -= 0.5;
+
+        dx -= dn * pihi.d;
+        dx -= dn * pilo.d;
+
+        xSq = SQ(dx);
+
+        polyApprox = ((P[4].d * xSq + P[3].d) * xSq + P[2].d) * xSq + P[1].d;
+
+        result = dx + (dx * xSq) * polyApprox;
+
+        if (!(n & 1)) {
+            return (f32)result;
+        }
+
+        return -(f32)result;
+    }
+
+    if (x != x) {
+        return __libm_qnan_f;
+    }
+
+    return zero.f;
+}