The first commit

src/core1/code_1E6E0.c

@@ -0,0 +1,47 @@
+#include <ultra64.h>
+#include "functions.h"
+#include "variables.h"
+
+// transform seed (in mips3 file)
+u32 func_8025C29C(u32 *seed);
+
+void glcrc_calc_checksum(void *start, void *end, u32 checksum[2])
+{
+    u8 *p;
+
+    u32 shift = 0;
+
+    u64 seed = 0x8F809F473108B3C1;
+
+    u32 crc1 = 0;
+    u32 crc2 = 0;
+
+    u32 tmp;
+
+    // CRC1: Iterate forwards over bytes
+    for (p = start; (void *)p < end; p++)
+    {
+        seed += *p << (shift & 15);
+
+        tmp = func_8025C29C(&seed);
+
+        shift += 7;
+
+        crc1 ^= tmp;
+    }
+
+    // CRC2: Iterate backwards over bytes
+    for (p = (u8 *)end - 1; (void *)p >= start; p--)
+    {
+        seed += *p << (shift & 15);
+
+        tmp = func_8025C29C(&seed);
+
+        shift += 3;
+
+        crc2 ^= tmp;
+    }
+
+    checksum[0] = crc1;
+    checksum[1] = crc2;
+}