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#include "global.h"
void Overlay_Relocate(void* allocatedVRamAddress, OverlayRelocationSection* overlayInfo, void* vRamStart) {
u32 sections[4];
u32 relocatedValue;
u32 dbg;
u32 relocOffset;
u32 relocData;
uintptr_t unrelocatedAddress;
u32 i;
u32* relocDataP;
u32* luiRefs[32];
u32 luiVals[32];
uintptr_t relocatedAddress;
u32 reloc;
u32* luiInstRef;
uintptr_t allocu32 = (uintptr_t)allocatedVRamAddress;
u32* regValP;
u32 isLoNeg;
s32 pad;
relocOffset = 0;
relocatedValue = 0;
unrelocatedAddress = 0;
relocatedAddress = 0;
if (gOverlayLogSeverity >= 3) {
osSyncPrintf("DoRelocation(%08x, %08x, %08x)\n", allocatedVRamAddress, overlayInfo, vRamStart);
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_SECTION(reloc)] + RELOC_OFFSET(reloc));
relocData = *relocDataP;
switch (RELOC_TYPE_MASK(reloc)) {
case R_MIPS_32 << RELOC_TYPE_SHIFT:
// Handles 32-bit address relocation, used for things such as jump tables and pointers in data.
// Just relocate the full address.
// Check address is valid for relocation
if ((*relocDataP & 0x0F000000) == 0) {
relocOffset = *relocDataP - (uintptr_t)vRamStart;
relocatedValue = relocOffset + allocu32;
relocatedAddress = relocatedValue;
unrelocatedAddress = relocData;
*relocDataP = relocatedAddress;
}
break;
case R_MIPS_26 << RELOC_TYPE_SHIFT:
// Handles 26-bit address relocation, used for jumps and jals.
// Extract the address from the target field of the J-type MIPS instruction.
// Relocate the address and update the instruction.
unrelocatedAddress = PHYS_TO_K0((*relocDataP & 0x03FFFFFF) << 2);
relocOffset = unrelocatedAddress - (uintptr_t)vRamStart;
relocatedValue = (*relocDataP & 0xFC000000) | (((allocu32 + relocOffset) & 0x0FFFFFFF) >> 2);
relocatedAddress = PHYS_TO_K0((relocatedValue & 0x03FFFFFF) << 2);
*relocDataP = relocatedValue;
break;
case R_MIPS_HI16 << RELOC_TYPE_SHIFT:
// Handles relocation for a hi/lo pair, part 1.
// Store the reference to the LUI instruction (hi) using the `rt` register of the instruction.
// This will be updated later in the `R_MIPS_LO16` section.
luiRefs[(*relocDataP >> 0x10) & 0x1F] = relocDataP;
luiVals[(*relocDataP >> 0x10) & 0x1F] = *relocDataP;
break;
case R_MIPS_LO16 << RELOC_TYPE_SHIFT:
// Handles relocation for a hi/lo pair, part 2.
// Grab the stored LUI (hi) from the `R_MIPS_HI16` section using the `rs` register of the instruction.
// The full address is calculated, relocated, and then used to update both the LUI and lo instructions.
// If the lo part is negative, add 1 to the LUI value.
// Note: The lo instruction is assumed to have a signed immediate.
luiInstRef = luiRefs[(*relocDataP >> 0x15) & 0x1F];
regValP = &luiVals[(*relocDataP >> 0x15) & 0x1F];
// Check address is valid for relocation
if ((((*regValP << 0x10) + (s16)*relocDataP) & 0x0F000000) == 0) {
relocOffset = ((*regValP << 0x10) + (s16)*relocDataP) - (uintptr_t)vRamStart;
isLoNeg = (((relocOffset + allocu32) & 0x8000) ? 1 : 0);
unrelocatedAddress = (*luiInstRef << 0x10) + (s16)relocData;
*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_TYPE_MASK(reloc)) {
case R_MIPS_32 << RELOC_TYPE_SHIFT:
dbg = 0x16;
FALLTHROUGH;
case R_MIPS_26 << RELOC_TYPE_SHIFT:
dbg += 0xA;
FALLTHROUGH;
case R_MIPS_LO16 << RELOC_TYPE_SHIFT:
if (gOverlayLogSeverity >= 3) {
osSyncPrintf("%02d %08x %08x %08x ", dbg, relocDataP, relocatedValue, relocatedAddress);
osSyncPrintf(" %08x %08x %08x %08x\n", (uintptr_t)relocDataP + (uintptr_t)vRamStart - allocu32,
relocData, unrelocatedAddress, relocOffset);
}
// Adding a break prevents matching
}
}
}
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