+ static void replaceWithJump(void* instructionStart, void* to)
+ {
+ ARMWord* instruction = reinterpret_cast<ARMWord*>(instructionStart);
+ intptr_t difference = reinterpret_cast<intptr_t>(to) - (reinterpret_cast<intptr_t>(instruction) + DefaultPrefetchOffset * sizeof(ARMWord));
+
+ if (!(difference & 1)) {
+ difference >>= 2;
+ if ((difference <= MaximumBranchOffsetDistance && difference >= MinimumBranchOffsetDistance)) {
+ // Direct branch.
+ instruction[0] = B | AL | (difference & BranchOffsetMask);
+ cacheFlush(instruction, sizeof(ARMWord));
+ return;
+ }
+ }
+
+ // Load target.
+ instruction[0] = LoadUint32 | AL | RN(ARMRegisters::pc) | RD(ARMRegisters::pc) | 4;
+ instruction[1] = reinterpret_cast<ARMWord>(to);
+ cacheFlush(instruction, sizeof(ARMWord) * 2);
+ }
+
+ static ptrdiff_t maxJumpReplacementSize()
+ {
+ return sizeof(ARMWord) * 2;
+ }
+
+ static void replaceWithLoad(void* instructionStart)
+ {
+ ARMWord* instruction = reinterpret_cast<ARMWord*>(instructionStart);
+ cacheFlush(instruction, sizeof(ARMWord));
+
+ ASSERT((*instruction & LdrOrAddInstructionMask) == AddImmediateInstruction || (*instruction & LdrOrAddInstructionMask) == LdrImmediateInstruction);
+ if ((*instruction & LdrOrAddInstructionMask) == AddImmediateInstruction) {
+ *instruction = (*instruction & ~LdrOrAddInstructionMask) | LdrImmediateInstruction;
+ cacheFlush(instruction, sizeof(ARMWord));
+ }
+ }
+
+ static void replaceWithAddressComputation(void* instructionStart)
+ {
+ ARMWord* instruction = reinterpret_cast<ARMWord*>(instructionStart);
+ cacheFlush(instruction, sizeof(ARMWord));
+
+ ASSERT((*instruction & LdrOrAddInstructionMask) == AddImmediateInstruction || (*instruction & LdrOrAddInstructionMask) == LdrImmediateInstruction);
+ if ((*instruction & LdrOrAddInstructionMask) == LdrImmediateInstruction) {
+ *instruction = (*instruction & ~LdrOrAddInstructionMask) | AddImmediateInstruction;
+ cacheFlush(instruction, sizeof(ARMWord));
+ }
+ }
+
+ static void revertBranchPtrWithPatch(void* instructionStart, RegisterID rn, ARMWord imm)
+ {
+ ARMWord* instruction = reinterpret_cast<ARMWord*>(instructionStart);
+
+ ASSERT((instruction[2] & LdrPcImmediateInstructionMask) == LdrPcImmediateInstruction);
+ instruction[0] = toARMWord(AL) | ((instruction[2] & 0x0fff0fff) + sizeof(ARMWord)) | RD(ARMRegisters::S1);
+ *getLdrImmAddress(instruction) = imm;
+ instruction[1] = toARMWord(AL) | CMP | SetConditionalCodes | RN(rn) | RM(ARMRegisters::S1);
+ cacheFlush(instruction, 2 * sizeof(ARMWord));
+ }
+