Move non-libultra libc functions to src/libc/ (#2055)

* Move non-libultra libc functions to src/libc/

* Add explicit nops in delay slots

* Don't rely on CPP expanding undefined macros to 0

* Delete old Makefile rules

* Fix type of memset()

5 files changed, 111 insertions, 0 deletions

diff --git a/src/libc/absf.s b/src/libc/absf.s
new file mode 100644
index 000000000..9df0c0a38
--- /dev/null
+++ b/src/libc/absf.s
@@ -0,0 +1,15 @@
+#include "ultra64/asm.h"
+
+#if OOT_DEBUG
+.set noreorder
+#endif
+
+.section .text
+
+.balign 16
+
+LEAF(absf)
+    abs.s       $f0, $f12
+    jr          $ra
+     nop
+END(absf)
diff --git a/src/libc/fmodf.c b/src/libc/fmodf.c
new file mode 100644
index 000000000..4ebec43bd
--- /dev/null
+++ b/src/libc/fmodf.c
@@ -0,0 +1,27 @@
+#include "ultra64.h"
+
+/**
+ * Computes one `x` modulo `y` for floats.
+ *
+ * Acts like the standard C fmodf except does not handle Infinity. See https://en.cppreference.com/w/c/numeric/math/fmod
+ * for the details. It summarizes this function as follows:
+ * "The floating-point remainder of the division operation x/y calculated by this function is exactly the value x - n*y,
+ * where n is x/y with its fractional part truncated.
+ *
+ * The returned value has the same sign as x and is less or equal to y in magnitude."
+ *
+ * @param x dividend
+ * @param y modulus
+ *
+ * @return f32 0.0f if y is 0.0f, or x modulo y otherwise
+ */
+f32 fmodf(f32 x, f32 y) {
+    s32 n;
+
+    if (y == 0.0f) {
+        return 0.0f;
+    }
+    n = x / y;
+
+    return x - (n * y);
+}
diff --git a/src/libc/memmove.c b/src/libc/memmove.c
new file mode 100644
index 000000000..8ff5ec5f6
--- /dev/null
+++ b/src/libc/memmove.c
@@ -0,0 +1,33 @@
+#include "global.h"
+
+/**
+ * memmove: copies `len` bytes from memory starting at `src` to memory starting at `dest`.
+ *
+ * Unlike memcpy(), the regions of memory may overlap.
+ *
+ * @param dest address of start of buffer to write to
+ * @param src address of start of buffer to read from
+ * @param len number of bytes to copy.
+ *
+ * @return dest
+ */
+void* memmove(void* dest, const void* src, size_t len) {
+    u8* d = dest;
+    const u8* s = src;
+
+    if (d == s) {
+        return dest;
+    }
+    if (d < s) {
+        while (len--) {
+            *d++ = *s++;
+        }
+    } else {
+        d += len - 1;
+        s += len - 1;
+        while (len--) {
+            *d-- = *s--;
+        }
+    }
+    return dest;
+}
diff --git a/src/libc/memset.c b/src/libc/memset.c
new file mode 100644
index 000000000..ec699c7ce
--- /dev/null
+++ b/src/libc/memset.c
@@ -0,0 +1,21 @@
+#include "global.h"
+
+/**
+ * memset: sets `len` bytes to `val` starting at address `dest`.
+ *
+ * @see There are two other memsets in this codebase, Lib_MemSet(), MemSet()
+ *
+ * @param dest address to start at
+ * @param val value to write (int, but interpreted as u8)
+ * @param len number of bytes to write
+ *
+ * @return dest
+ */
+void* memset(void* dest, int val, size_t len) {
+    u8* ptr = dest;
+
+    while (len--) {
+        *ptr++ = val;
+    }
+    return dest;
+}
diff --git a/src/libc/sqrt.s b/src/libc/sqrt.s
new file mode 100644
index 000000000..b4246ec86
--- /dev/null
+++ b/src/libc/sqrt.s
@@ -0,0 +1,15 @@
+#include "ultra64/asm.h"
+
+#if OOT_DEBUG
+.set noreorder
+#endif
+
+.section .text
+
+.balign 16
+
+LEAF(sqrt)
+    sqrt.d      $f0, $f12
+    jr          $ra
+     nop
+END(sqrt)