1 files changed, 85 insertions, 7 deletions
diff --git a/src/code/sys_math.c b/src/code/sys_math.c
index 4142cd598..9b274c7e2 100644
--- a/src/code/sys_math.c
+++ b/src/code/sys_math.c
@@ -1,15 +1,93 @@
+/**
+ * Maths library: two factorials, integer power, wrappers for libultra's sins and coss (the main ones used), and some
+ * random functions moved from OoT's z_actor
+ */
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/func_80179300.s")
+static f32 sFactorialTbl[] = { 1.0f,    1.0f,     2.0f,      6.0f,       24.0f,       120.0f,      720.0f,
+                               5040.0f, 40320.0f, 362880.0f, 3628800.0f, 39916800.0f, 479001600.0f };
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/func_80179400.s")
+// Rename to Math_FactorialF
+/**
+ * Takes a float, returns the factorial of it(s trunctation), iteratively
+ * Unused
+ */
+f32 func_80179300(f32 n) {
+    f32 ret = 1.0f;
+    s32 i;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/pow_int.s")
+    //! @bug No check for negative argument. Will return 1.0f if the argument truncates to a negative int.
+    for (i = n; i > 1; i--) {
+        ret *= i;
+    }
+    return ret;
+}
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/sin_rad.s")
+// Rename to Math_Factorial
+/**
+ * Takes an int and returns its factorial as a float. Uses the lookup table for n <= 12.
+ * Unused
+ */
+f32 func_80179400(s32 n) {
+    f32 ret;
+    s32 i;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/cos_rad.s")
+    //! @bug No check for negative argument. Will read the array out-of-bounds if the argument is negative.
+    //! (The OoT version does an unsigned check instead, which will return sFactorialTbl[12] for a negative argument.)
+    if (n > 12) {
+        ret = sFactorialTbl[12];
+        for (i = 13; i <= n; i++) {
+            ret *= i;
+        }
+    } else {
+        ret = sFactorialTbl[n];
+    }
+    return ret;
+}
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/Rand_ZeroFloat.s")
+// Rename to Math_PowF
+/**
+ * Returns base^{exp} if exp is nonnegative and 1.0f otherwise.
+ * Unused
+ */
+f32 pow_int(f32 base, s32 exp) {
+    f32 ret = 1.0f;
 
-#pragma GLOBAL_ASM("asm/non_matchings/code/sys_math/randPlusMinusPoint5Scaled.s")
+    while (exp > 0) {
+        exp--;
+        ret *= base;
+    }
+
+    return ret;
+}
+
+// Rename to Math_SinF
+/**
+ * Takes an angle in radians and returns the sine.
+ */
+f32 sin_rad(f32 rad) {
+    return sins(RADF_TO_BINANG(rad)) * SHT_MINV;
+}
+
+// Rename to Math_CosF
+/**
+ * Takes an angle in radians and returns the cosine.
+ */
+f32 cos_rad(f32 rad) {
+    return coss(RADF_TO_BINANG(rad)) * SHT_MINV;
+}
+
+/**
+ * Returns a pseudo-random floating-point number between 0.0f and scale. Originally in z_actor in OoT.
+ */
+f32 Rand_ZeroFloat(f32 scale) {
+    return Rand_ZeroOne() * scale;
+}
+
+// Rename to Rand_CenteredFloat
+/**
+ * Returns a pseudo-random floating-point number between (- scale / 2) and (scale / 2). Originally in z_actor in OoT.
+ */
+f32 randPlusMinusPoint5Scaled(f32 scale) {
+    return Rand_Centered() * scale;
+}