Add emulation methods for "RSC (immediate)" and "RSC (register)" operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@126267 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp b/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
index 2c090c0..216c7b3 100644
--- a/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
+++ b/source/Plugins/Instruction/ARM/EmulateInstructionARM.cpp
@@ -5080,7 +5080,7 @@
addr_t address;
// offset = Shift(R[m], shift_t, shift_n, APSR.C); -- Note "The APSR is an application level alias for the CPSR".
- addr_t offset = Shift (Rm, shift_t, shift_n, Bit32 (m_inst_cpsr, CPSR_C));
+ addr_t offset = Shift (Rm, shift_t, shift_n, Bit32 (m_inst_cpsr, APSR_C));
// offset_addr = if add then (R[n] + offset) else (R[n] - offset);
if (add)
@@ -6032,6 +6032,139 @@
return true;
}
+// Reverse Subtract with Carry (immediate) subtracts a register value and the value of NOT (Carry flag) from
+// an immediate value, and writes the result to the destination register. It can optionally update the condition
+// flags based on the result.
+bool
+EmulateInstructionARM::EmulateRSCImm (ARMEncoding encoding)
+{
+#if 0
+ // ARM pseudo code...
+ if ConditionPassed() then
+ EncodingSpecificOperations();
+ (result, carry, overflow) = AddWithCarry(NOT(R[n]), imm32, APSR.C);
+ if d == 15 then
+ ALUWritePC(result); // setflags is always FALSE here
+ else
+ R[d] = result;
+ if setflags then
+ APSR.N = result<31>;
+ APSR.Z = IsZeroBit(result);
+ APSR.C = carry;
+ APSR.V = overflow;
+#endif
+
+ bool success = false;
+ const uint32_t opcode = OpcodeAsUnsigned (&success);
+ if (!success)
+ return false;
+
+ uint32_t Rd; // the destination register
+ uint32_t Rn; // the first operand
+ bool setflags;
+ uint32_t imm32; // the immediate value to be added to the value obtained from Rn
+ switch (encoding) {
+ case eEncodingA1:
+ Rd = Bits32(opcode, 15, 12);
+ Rn = Bits32(opcode, 19, 16);
+ setflags = BitIsSet(opcode, 20);
+ imm32 = ARMExpandImm(opcode); // imm32 = ARMExpandImm(imm12)
+ // if Rd == '1111' && S == '1' then SEE SUBS PC, LR and related instructions;
+ // TODO: Emulate SUBS PC, LR and related instructions.
+ if (Rd == 15 && setflags)
+ return false;
+ break;
+ default:
+ return false;
+ }
+ // Read the register value from the operand register Rn.
+ uint32_t reg_val = ReadCoreReg(Rn, &success);
+ if (!success)
+ return false;
+
+ AddWithCarryResult res = AddWithCarry(~reg_val, imm32, APSR_C);
+
+ EmulateInstruction::Context context;
+ context.type = EmulateInstruction::eContextImmediate;
+ context.SetNoArgs ();
+
+ if (!WriteCoreRegOptionalFlags(context, res.result, Rd, setflags, res.carry_out, res.overflow))
+ return false;
+
+ return true;
+}
+
+// Reverse Subtract with Carry (register) subtracts a register value and the value of NOT (Carry flag) from an
+// optionally-shifted register value, and writes the result to the destination register. It can optionally update the
+// condition flags based on the result.
+bool
+EmulateInstructionARM::EmulateRSCReg (ARMEncoding encoding)
+{
+#if 0
+ // ARM pseudo code...
+ if ConditionPassed() then
+ EncodingSpecificOperations();
+ shifted = Shift(R[m], shift_t, shift_n, APSR.C);
+ (result, carry, overflow) = AddWithCarry(NOT(R[n]), shifted, APSR.C);
+ if d == 15 then
+ ALUWritePC(result); // setflags is always FALSE here
+ else
+ R[d] = result;
+ if setflags then
+ APSR.N = result<31>;
+ APSR.Z = IsZeroBit(result);
+ APSR.C = carry;
+ APSR.V = overflow;
+#endif
+
+ bool success = false;
+ const uint32_t opcode = OpcodeAsUnsigned (&success);
+ if (!success)
+ return false;
+
+ uint32_t Rd; // the destination register
+ uint32_t Rn; // the first operand
+ uint32_t Rm; // the second operand
+ bool setflags;
+ ARM_ShifterType shift_t;
+ uint32_t shift_n; // the shift applied to the value read from Rm
+ switch (encoding) {
+ case eEncodingA1:
+ Rd = Bits32(opcode, 15, 12);
+ Rn = Bits32(opcode, 19, 16);
+ Rm = Bits32(opcode, 3, 0);
+ setflags = BitIsSet(opcode, 20);
+ shift_n = DecodeImmShiftARM(opcode, shift_t);
+ // if Rd == '1111' && S == '1' then SEE SUBS PC, LR and related instructions;
+ // TODO: Emulate SUBS PC, LR and related instructions.
+ if (Rd == 15 && setflags)
+ return false;
+ break;
+ default:
+ return false;
+ }
+ // Read the register value from register Rn.
+ uint32_t val1 = ReadCoreReg(Rn, &success);
+ if (!success)
+ return false;
+
+ // Read the register value from register Rm.
+ uint32_t val2 = ReadCoreReg(Rm, &success);
+ if (!success)
+ return false;
+
+ uint32_t shifted = Shift(val2, shift_t, shift_n, APSR_C);
+ AddWithCarryResult res = AddWithCarry(~val1, shifted, APSR_C);
+
+ EmulateInstruction::Context context;
+ context.type = EmulateInstruction::eContextImmediate;
+ context.SetNoArgs();
+ if (!WriteCoreRegOptionalFlags(context, res.result, Rd, setflags, res.carry_out, res.overflow))
+ return false;
+
+ return true;
+}
+
// Test Equivalence (immediate) performs a bitwise exclusive OR operation on a register value and an
// immediate value. It updates the condition flags based on the result, and discards the result.
bool
@@ -6380,6 +6513,10 @@
{ 0x0fe00000, 0x02600000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateRSBImm, "rsb{s}<c> <Rd>, <Rn>, #<const>"},
// rsb (register)
{ 0x0fe00010, 0x00600000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateRSBReg, "rsb{s}<c> <Rd>, <Rn>, <Rm> {,<shift>}"},
+ // rsc (immediate)
+ { 0x0fe00000, 0x02e00000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateRSCImm, "rsc{s}<c> <Rd>, <Rn>, #<const>"},
+ // rsc (register)
+ { 0x0fe00010, 0x00e00000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateRSCReg, "rsc{s}<c> <Rd>, <Rn>, <Rm> {,<shift>}"},
// teq (immediate)
{ 0x0ff0f000, 0x03300000, ARMvAll, eEncodingA1, eSize32, &EmulateInstructionARM::EmulateTEQImm, "teq<c> <Rn>, #const"},
// teq (register)
diff --git a/source/Plugins/Instruction/ARM/EmulateInstructionARM.h b/source/Plugins/Instruction/ARM/EmulateInstructionARM.h
index 01ccdff..ec7c9d9 100644
--- a/source/Plugins/Instruction/ARM/EmulateInstructionARM.h
+++ b/source/Plugins/Instruction/ARM/EmulateInstructionARM.h
@@ -653,21 +653,21 @@
bool
EmulatePLIRegister (ARMEncoding encoding);
- // A8.6.141 RSB (immediate) - Encoding T1, A1
+ // A8.6.141 RSB (immediate)
bool
EmulateRSBImm (ARMEncoding encoding);
- // A8.6.142 RSB (register) - Encoding A1
+ // A8.6.142 RSB (register)
bool
EmulateRSBReg (ARMEncoding encoding);
- // A8.6.144 RSC (immediate) - Encoding A1
+ // A8.6.144 RSC (immediate)
bool
- EmulateRSCImmediate (ARMEncoding encoding);
+ EmulateRSCImm (ARMEncoding encoding);
- // A8.6.145 RSC (register) - Encoding A1
+ // A8.6.145 RSC (register)
bool
- EmulateRSCRegister (ARMEncoding encoding);
+ EmulateRSCReg (ARMEncoding encoding);
// A8.6.150 SBC (immediate) - Encoding A1
bool