From 0cf75356a557e94f7919521ff9ad53e4b733ac20 Mon Sep 17 00:00:00 2001
From: glank <tommy.bergman91@gmail.com>
Date: Sat, 21 Mar 2020 03:09:42 +0100
Subject: code_800FCE80 OK

---
 src/code/code_800FCE80.c | 229 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 229 insertions(+)
 create mode 100644 src/code/code_800FCE80.c

(limited to 'src/code/code_800FCE80.c')

diff --git a/src/code/code_800FCE80.c b/src/code/code_800FCE80.c
new file mode 100644
index 000000000..60afd1dfb
--- /dev/null
+++ b/src/code/code_800FCE80.c
@@ -0,0 +1,229 @@
+#include <ultra64.h>
+#include <global.h>
+#include <fp.h>
+
+s32 use_cfrac;
+
+f32 Math_tanf(f32 x)
+{
+    f32 sin = sinf(x);
+    f32 cos = cosf(x);
+    return sin / cos;
+}
+
+f32 Math_floorf(f32 x)
+{
+    return floorf(x);
+}
+
+f32 Math_ceilf(f32 x)
+{
+    return ceilf(x);
+}
+
+f32 Math_roundf(f32 x)
+{
+    return roundf(x);
+}
+
+f32 Math_truncf(f32 x)
+{
+    return truncf(x);
+}
+
+f32 Math_nearbyintf(f32 x)
+{
+    return nearbyintf(x);
+}
+
+/* Arctangent approximation using a Taylor series (one quadrant) */
+f32 Math_atanf_taylor_q(f32 x)
+{
+    static const f32 coeffs[] =
+    {
+        -1.f / 3,
+        +1.f / 5,
+        -1.f / 7,
+        +1.f / 9,
+        -1.f / 11,
+        +1.f / 13,
+        -1.f / 15,
+        +1.f / 17,
+        0.f,
+    };
+
+    f32 poly = x;
+    f32 sq = SQ(x);
+    f32 exp = x * sq;
+    const f32 *c = coeffs;
+    f32 term;
+
+    while (1)
+    {
+        term = *c++ * exp;
+        if (poly + term == poly)
+        {
+            break;
+        }
+        poly = poly + term;
+        exp = exp * sq;
+    }
+
+    return poly;
+}
+
+/* Ditto for two quadrants */
+f32 Math_atanf_taylor(f32 x)
+{
+    f32 t;
+    f32 q;
+
+    if (x > 0.f)
+    {
+        t = x;
+    }
+    else if (x < 0.f)
+    {
+        t = -x;
+    }
+    else if (x == 0.f)
+    {
+        return 0.f;
+    }
+    else
+    {
+        return qNaN0x10000;
+    }
+
+    if (t <= M_SQRT2 - 1.f)
+    {
+        return Math_atanf_taylor_q(x);
+    }
+
+    if (t >= M_SQRT2 + 1.f)
+    {
+        q = M_PI / 2 - Math_atanf_taylor_q(1.f / t);
+    }
+    else
+    {
+        q = M_PI / 4 - Math_atanf_taylor_q((1.f - t) / (1.f + t));
+    }
+
+    if (x > 0.f)
+    {
+        return q;
+    }
+    else
+    {
+        return -q;
+    }
+}
+
+/* Arctangent approximation using a continued fraction */
+f32 Math_atanf_cfrac(f32 x)
+{
+    s32 sector;
+    f32 z;
+    f32 conv;
+    f32 sq;
+    s32 i;
+
+    if (x >= -1.f && x <= 1.f)
+    {
+        sector = 0;
+    }
+    else if (x > 1.f)
+    {
+        sector = 1;
+        x = 1.f / x;
+    }
+    else if (x < -1.f)
+    {
+        sector = -1;
+        x = 1.f / x;
+    }
+    else
+    {
+        return qNaN0x10000;
+    }
+
+    sq = SQ(x);
+    conv = 0.f;
+    z = 8.f;
+    for (i = 8; i != 0; i--)
+    {
+        conv = SQ(z) * sq / (2.f * z + 1.f + conv);
+        z -= 1.f;
+    }
+    conv = x / (1.f + conv);
+
+    if (sector == 0)
+    {
+        return conv;
+    }
+    else if (sector > 0)
+    {
+        return M_PI / 2 - conv;
+    }
+    else
+    {
+        return -M_PI / 2 - conv;
+    }
+}
+
+f32 Math_atanf(f32 x)
+{
+    if (use_cfrac == 0)
+    {
+        return Math_atanf_taylor(x);
+    }
+    else
+    {
+        return Math_atanf_cfrac(x);
+    }
+}
+
+f32 Math_atan2f(f32 y, f32 x)
+{
+    if (x == 0.f)
+    {
+        if (y == 0.f)
+        {
+            return 0.f;
+        }
+        else if (y > 0.f)
+        {
+            return M_PI / 2;
+        }
+        else if (y < 0.f)
+        {
+            return -M_PI / 2;
+        }
+        else
+        {
+            return qNaN0x10000;
+        }
+    }
+    else if (x >= 0.f)
+    {
+        return Math_atanf(y / x);
+    }
+    else if (y < 0.f)
+    {
+        return Math_atanf(y / x) - M_PI;
+    }
+    else
+    {
+        return M_PI - Math_atanf(-(y / x));
+    }
+}
+
+f32 Math_asinf(f32 x)
+{
+    return Math_atan2f(x, sqrtf(1.f - SQ(x)));
+}
+
+f32 Math_acosf(f32 x)
+{
+    return M_PI / 2 - Math_asinf(x);
+}
-- 
cgit v1.2.3