diff --git a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp index 6e861cb10fb6..e99c2b42f030 100644 --- a/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp +++ b/lldb/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp @@ -6024,6 +6024,117 @@ EmulateInstructionARM::EmulateLDRHImmediate (ARMEncoding encoding) return true; } +// LDRH (literal) caculates an address from the PC value and an immediate offset, loads a halfword from memory, +// zero-extends it to form a 32-bit word, and writes it to a register. +bool +EmulateInstructionARM::EmulateLDRHLiteral (ARMEncoding encoding) +{ +#if 0 + if ConditionPassed() then + EncodingSpecificOperations(); NullCheckIfThumbEE(15); + base = Align(PC,4); + address = if add then (base + imm32) else (base - imm32); + data = MemU[address,2]; + if UnalignedSupport() || address<0> = ’0’ then + R[t] = ZeroExtend(data, 32); + else // Can only apply before ARMv7 + R[t] = bits(32) UNKNOWN; +#endif + + + bool success = false; + const uint32_t opcode = OpcodeAsUnsigned (&success); + if (!success) + return false; + + if (ConditionPassed()) + { + uint32_t t; + uint32_t imm32; + bool add; + + // EncodingSpecificOperations(); NullCheckIfThumbEE(15); + switch (encoding) + { + case eEncodingT1: + // if Rt == ’1111’ then SEE "Unallocated memory hints"; + // t = UInt(Rt); imm32 = ZeroExtend(imm12, 32); add = (U == ’1’); + t = Bits32 (opcode, 15, 12); + imm32 = Bits32 (opcode, 11, 0); + add = BitIsSet (opcode, 23); + + // if t == 13 then UNPREDICTABLE; + if (t == 13) + return false; + + break; + + case eEncodingA1: + { + uint32_t imm4H = Bits32 (opcode, 11, 8); + uint32_t imm4L = Bits32 (opcode, 3, 0); + + // t == UInt(Rt); imm32 = ZeroExtend(imm4H:imm4L, 32); add = (U == ’1’); + t = Bits32 (opcode, 15, 12); + imm32 = (imm4H << 4) & imm4L; + add = BitIsSet (opcode, 23); + + // if t == 15 then UNPREDICTABLE; + if (t == 15) + return false; + break; + } + + default: + return false; + } + + // base = Align(PC,4); + uint64_t pc_value = ReadRegisterUnsigned (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, 0, &success); + if (!success) + return false; + + addr_t base = AlignPC (pc_value); + addr_t address; + + // address = if add then (base + imm32) else (base - imm32); + if (add) + address = base + imm32; + else + address = base - imm32; + + // data = MemU[address,2]; + Register base_reg; + base_reg.SetRegister (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC); + + EmulateInstruction::Context context; + context.type = eContextRegisterLoad; + context.SetRegisterPlusOffset (base_reg, address - base); + + uint64_t data = MemURead (context, address, 2, 0, &success); + if (!success) + return false; + + + // if UnalignedSupport() || address<0> = ’0’ then + if (UnalignedSupport () || BitIsClear (address, 0)) + { + // R[t] = ZeroExtend(data, 32); + context.type = eContextRegisterLoad; + context.SetRegisterPlusOffset (base_reg, address - base); + if (!WriteRegisterUnsigned (context, eRegisterKindDWARF, dwarf_r0 + t, data)) + return false; + + } + else // Can only apply before ARMv7 + { + // R[t] = bits(32) UNKNOWN; + WriteBits32Unknown (t); + } + } + return true; +} + // Bitwise Exclusive OR (immediate) performs a bitwise exclusive OR of a register value and an immediate value, // and writes the result to the destination register. It can optionally update the condition flags based on // the result. @@ -7396,6 +7507,7 @@ EmulateInstructionARM::GetARMOpcodeForInstruction (const uint32_t opcode) { 0x0e500010, 0x06100000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDRRegister, "ldr [ +/- {}] {!}" }, { 0x0e5f0000, 0x045f0000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDRBLiteral, "ldrb , [...]"}, { 0xfe500010, 0x06500000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDRBRegister, "ldrb , [,+/-{, }]{!}" }, + { 0x0e5f00f0, 0x005f00b0, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateLDRHLiteral, "ldrh ,