public static void Stm(ArmEmitterContext context)
{
IOpCode32MemMult op = (IOpCode32MemMult)context.CurrOp;
Operand n = context.Copy(GetIntA32(context, op.Rn));
Operand baseAddress = context.Add(n, Const(op.Offset));
int mask = op.RegisterMask;
int offset = 0;
for (int register = 0; mask != 0; mask >>= 1, register++)
{
if ((mask & 1) != 0)
{
Operand address = context.Add(baseAddress, Const(offset));
EmitStore(context, address, register, WordSizeLog2);
// Note: If Rn is also specified on the register list,
// and Rn is the first register on this list, then the
// value that is written to memory is the unmodified value,
// before the write back. If it is on the list, but it's
// not the first one, then the value written to memory
// varies between CPUs.
if (offset == 0 && op.PostOffset != 0)
{
// Emit write back after the first write.
SetIntA32(context, op.Rn, context.Add(n, Const(op.PostOffset)));
}
offset += 4;
}
}
}
public static void Ldm(ArmEmitterContext context)
{
IOpCode32MemMult op = (IOpCode32MemMult)context.CurrOp;
Operand n = GetIntA32(context, op.Rn);
Operand baseAddress = context.Add(n, Const(op.Offset));
bool writesToPc = (op.RegisterMask & (1 << RegisterAlias.Aarch32Pc)) != 0;
bool writeBack = op.PostOffset != 0 && (op.Rn != RegisterAlias.Aarch32Pc || !writesToPc);
if (writeBack)
{
SetIntA32(context, op.Rn, context.Add(n, Const(op.PostOffset)));
}
int mask = op.RegisterMask;
int offset = 0;
for (int register = 0; mask != 0; mask >>= 1, register++)
{
if ((mask & 1) != 0)
{
Operand address = context.Add(baseAddress, Const(offset));
EmitLoadZx(context, address, register, WordSizeLog2);
offset += 4;
}
}
}
