`Common Language Runtime detected an invalid program` error generating simple dynamic method

I'm working on a JIT compiler for MIPS machine emulation to translate MIPS to CLI. I'm working on getting a nearly hard-coded Shift method, but whenever I try to execute the operation instruction on a value loaded from memory it fails.

This is the code that fails giving the Common Language Runtime detected an invalid program exception message:

private unsafe bool Shift(ILGenerator il, MipsInstruction inst, OpCode ilOpCode) { long baseAddress = (long)_cpu.RegisterFile.Regs; long regAddress = baseAddress + ((int)inst.RT * sizeof(T)); // Push Address if (IntPtr.Size == 4) il.Emit(OpCodes.Ldc_I4, (int)regAddress); else il.Emit(OpCodes.Ldc_I8, regAddress); il.Emit(OpCodes.Conv_I); // Load the value from memory il.Emit(OpCodes.Ldind_U4); // Load shift amount il.Emit(OpCodes.Ldc_I4, inst.ShiftAmount); // Apply shift il.Emit(ilOpCode); // Pop value (not even trying to store yet) il.Emit(OpCodes.Pop); return false; }

_cpu.RegisterFile.Regs is a T* where T is either a uint or a ulong depending on if the configurated MIPS version is 32 or 64 bit. In my testing I've been using MIPS32R2, so it's a uint.

For additional info, the following two methods do not give the exception:

private unsafe bool Shift(ILGenerator il, MipsInstruction inst, OpCode ilOpCode) { il.Emit(OpCodes.Ldc_I4, inst.ShiftAmount); il.Emit(OpCodes.Ldc_I4, inst.ShiftAmount); il.Emit(ilOpCode); il.Emit(OpCodes.Pop); return false; } private unsafe bool Shift(ILGenerator il, MipsInstruction inst, OpCode ilOpCode) { long baseAddress = (long)_cpu.RegisterFile.Regs; long regAddress = baseAddress + ((int)inst.RT * sizeof(T)); // Push Address if (IntPtr.Size == 4) il.Emit(OpCodes.Ldc_I4, (int)regAddress); else il.Emit(OpCodes.Ldc_I8, regAddress); il.Emit(OpCodes.Conv_I); // Load the value from memory il.Emit(OpCodes.Ldind_U4); il.Emit(OpCodes.Pop); return false; }

Finally, here is a permalink to a still broken version, which contains the surrounding code: permalink