Memstuff (#1164)

* Un-fake a couple of matches in memory manip functions

* Document fmodf

* Un-fake a couple of matches in memory manip functions

* Document fmodf

* Rename functions and files

* Document memmove, memsets, memcpys

* Format

* Sort out some missing sizeofs

* Name fmodf

* Rename local variables

* size_t

* Use COBRA_SHADOW_TEX_SIZE

* Review

* Tweak the Doxyfile to remove @brief requirement

* Roman's review

* Fix a bug comment

* Change fmodf

src/code/code_80069420.c

@@ -1,23 +1,47 @@
 #include "global.h"
 
-void* MemCopy(void* dest, void* src, s32 size) {
-    u8* destu = (u8*)dest;
-    u8* srcu = (u8*)src;
+/**
+ * memcpy: copies `len` bytes from memory starting at `src` to memory starting at `dest`. Expects the memory
+ * specified by `src` and `dest` to not overlap.
+ *
+ * @see libultra also has a memcpy().
+ *
+ * @param dest address of start of buffer writing to
+ * @param src address of start of buffer to read from
+ * @param len number of bytes to copy. (`s32` rather than the standard `size_t`)
+ *
+ * @return dest
+ */
+void* MemCpy(void* dest, const void* src, s32 len) {
+    u8* d = dest;
+    const u8* s = src;
 
-    while (size > 0) {
-        *destu++ = *srcu++;
-        size--;
+    while (len > 0) {
+        *d++ = *s++;
+        len--;
     }
 
     return dest;
 }
 
-void* MemSet(void* dest, s32 val, s32 size) {
-    u8* destu = (u8*)dest;
-    s32 s = size;
+/**
+ * memset: sets `len` bytes to `val` starting at address `dest`.
+ *
+ * @see There are two other memsets in this codebase, Lib_MemSet(), __osMemset().
+ * This one is unused.
+ *
+ * @param dest address to start at
+ * @param val value to write (`s32`, but interpreted as `u8`)
+ * @param len number of bytes to write. (`s32` rather than the standard `size_t`)
+ *
+ * @return dest
+ */
+void* MemSet(void* dest, s32 val, s32 len) {
+    u8* d = dest;
+    s32 s = len;
 
     while (s > 0) {
-        *destu++ = val;
+        *d++ = val;
         s--;
     }