/// <summary>
/// X86: Indicates whether an argument is to be put in a register using the
/// default IL calling convention. This should be called on each parameter
/// in the order it appears in the call signature. For a non-static meethod,
/// this function should also be called once for the "this" argument, prior
/// to calling it for the "real" arguments. Pass in a typ of ELEMENT_TYPE_CLASS.
/// </summary>
/// <param name="pNumRegistersUsed">
/// keeps track of the number of argument registers assigned previously.
/// The caller should initialize this variable to 0 - then each call will update it.
/// </param>
/// <param name="typ">parameter type</param>
/// <param name="thArgType">Exact type info is used to check struct enregistration</param>
public bool IsArgumentInRegister(ref int pNumRegistersUsed, CorElementType typ, TypeHandle thArgType)
{
Debug.Assert(IsX86);
// LIMITED_METHOD_CONTRACT;
if (pNumRegistersUsed < NumArgumentRegisters)
{
switch (typ)
{
case CorElementType.ELEMENT_TYPE_BOOLEAN:
case CorElementType.ELEMENT_TYPE_CHAR:
case CorElementType.ELEMENT_TYPE_I1:
case CorElementType.ELEMENT_TYPE_U1:
case CorElementType.ELEMENT_TYPE_I2:
case CorElementType.ELEMENT_TYPE_U2:
case CorElementType.ELEMENT_TYPE_I4:
case CorElementType.ELEMENT_TYPE_U4:
case CorElementType.ELEMENT_TYPE_STRING:
case CorElementType.ELEMENT_TYPE_PTR:
case CorElementType.ELEMENT_TYPE_BYREF:
case CorElementType.ELEMENT_TYPE_CLASS:
case CorElementType.ELEMENT_TYPE_ARRAY:
case CorElementType.ELEMENT_TYPE_I:
case CorElementType.ELEMENT_TYPE_U:
case CorElementType.ELEMENT_TYPE_FNPTR:
case CorElementType.ELEMENT_TYPE_OBJECT:
case CorElementType.ELEMENT_TYPE_SZARRAY:
pNumRegistersUsed++;
return(true);
#if PROJECTN
case CorElementType.ELEMENT_TYPE_VALUETYPE:
{
// On ProjectN valuetypes of integral size are passed enregistered
int structSize = TypeHandle.GetElemSize(typ, thArgType);
switch (structSize)
{
case 1:
case 2:
case 4:
pNumRegistersUsed++;
return(true);
}
break;
}
#elif READYTORUN
case CorElementType.ELEMENT_TYPE_VALUETYPE:
if (IsTrivialPointerSizedStruct(thArgType))
{
pNumRegistersUsed++;
return(true);
}
break;
#endif
}
}
return(false);
}