1 files changed, 113 insertions, 0 deletions
diff --git a/soh/src/code/relocation.c b/soh/src/code/relocation.c
new file mode 100644
index 000000000..a62ba3239
--- /dev/null
+++ b/soh/src/code/relocation.c
@@ -0,0 +1,113 @@
+#include "global.h"
+
+void Overlay_Relocate(void* allocatedVRamAddress, OverlayRelocationSection* overlayInfo, void* vRamAddress) {
+    u32 sections[4];
+    u32 relocatedValue;
+    u32 dbg;
+    u32 relocOffset;
+    u32 relocData;
+    uintptr_t unrelocatedAddress;
+    u32 i;
+    uintptr_t* relocDataP;
+    u32* luiRefs[32];
+    u32 luiVals[32];
+    uintptr_t relocatedAddress;
+    u32 reloc;
+    uintptr_t vaddr;
+    u32* luiInstRef;
+    uintptr_t allocu32 = (uintptr_t)allocatedVRamAddress;
+    u32* regValP;
+    u32 isLoNeg;
+
+    relocOffset = 0;
+    relocatedValue = 0;
+    unrelocatedAddress = 0;
+    relocatedAddress = 0;
+
+    if (gOverlayLogSeverity >= 3) {
+        osSyncPrintf("DoRelocation(%08x, %08x, %08x)\n", allocatedVRamAddress, overlayInfo, vRamAddress);
+        osSyncPrintf("text=%08x, data=%08x, rodata=%08x, bss=%08x\n", overlayInfo->textSize, overlayInfo->dataSize,
+                     overlayInfo->rodataSize, overlayInfo->bssSize);
+    }
+
+    sections[0] = 0;
+    sections[1] = allocu32;
+    sections[2] = allocu32 + overlayInfo->textSize;
+    sections[3] = sections[2] + overlayInfo->dataSize;
+
+    for (i = 0; i < overlayInfo->nRelocations; i++) {
+        reloc = overlayInfo->relocations[i];
+        relocDataP = (u32*)(sections[reloc >> 0x1E] + (reloc & 0xFFFFFF));
+        relocData = *relocDataP;
+        switch (reloc & 0x3F000000) {
+            case 0x2000000:
+                /* R_MIPS_32
+                 * Handles 32-bit address relocation.  Used in things such as
+                 * jump tables.
+                 */
+                if ((*relocDataP & 0xF000000) == 0) {
+                    luiInstRef = vRamAddress;
+                    relocOffset = *relocDataP - (uintptr_t)luiInstRef;
+                    relocatedValue = relocOffset + allocu32;
+                    relocatedAddress = relocatedValue;
+                    unrelocatedAddress = relocData;
+                    *relocDataP = relocatedAddress;
+                }
+                break;
+            case 0x4000000:
+                /* R_MIPS_26
+                 * Handles 26-bit address relocation, used for jumps and jals
+                 */
+                unrelocatedAddress = ((*relocDataP & 0x3FFFFFF) << 2) | 0x80000000;
+                relocOffset = unrelocatedAddress - (uintptr_t)vRamAddress;
+                relocatedValue = (*relocDataP & 0xFC000000) | (((allocu32 + relocOffset) & 0xFFFFFFF) >> 2);
+                relocatedAddress = ((relocatedValue & 0x3FFFFFF) << 2) | 0x80000000;
+                *relocDataP = relocatedValue;
+                break;
+            case 0x5000000:
+                /* R_MIPS_HI16
+                 * Handles relocation for a lui instruciton, store the reference to
+                 * the instruction, and will update it in the R_MIPS_LO16 section.
+                 */
+                luiRefs[(*relocDataP >> 0x10) & 0x1F] = relocDataP;
+                luiVals[(*relocDataP >> 0x10) & 0x1F] = *relocDataP;
+                break;
+            case 0x6000000:
+                /* R_MIPS_LO16
+                 * Updates the LUI instruction to reflect the relocated address.
+                 * The full address is calculated from the LUI and lo parts, and then updated.
+                 * if the lo part is negative, add 1 to the lui.
+                 */
+                regValP = &luiVals[((*relocDataP >> 0x15) & 0x1F)];
+                vaddr = (*regValP << 0x10) + (s16)*relocDataP;
+                luiInstRef = luiRefs[((*relocDataP >> 0x15) & 0x1F)];
+                if ((vaddr & 0xF000000) == 0) {
+                    relocOffset = vaddr - (uintptr_t)vRamAddress;
+                    vaddr = (s16)relocData;
+                    isLoNeg = (((relocOffset + allocu32) & 0x8000) ? 1 : 0);
+                    unrelocatedAddress = (*luiInstRef << 0x10) + vaddr;
+                    *luiInstRef =
+                        (*luiInstRef & 0xFFFF0000) | ((((relocOffset + allocu32) >> 0x10) & 0xFFFF) + isLoNeg);
+                    relocatedValue = (*relocDataP & 0xFFFF0000) | ((relocOffset + allocu32) & 0xFFFF);
+
+                    relocatedAddress = (*luiInstRef << 0x10) + (s16)relocatedValue;
+                    *relocDataP = relocatedValue;
+                }
+                break;
+        }
+
+        dbg = 0x10;
+        switch (reloc & 0x3F000000) {
+            case 0x2000000:
+                dbg = 0x16;
+            case 0x4000000:
+                dbg += 0xA;
+            case 0x6000000:
+                if (gOverlayLogSeverity >= 3) {
+                    osSyncPrintf("%02d %08x %08x %08x ", dbg, relocDataP, relocatedValue, relocatedAddress);
+                    osSyncPrintf(" %08x %08x %08x %08x\n", ((uintptr_t)relocDataP + (uintptr_t)vRamAddress) - allocu32, relocData,
+                                 unrelocatedAddress, relocOffset);
+                }
+        }
+    }
+}