public override Reg CGenValue(CGenState state) {
// %eax is the address of the struct/union
if (this.Expr.CGenValue(state) != Reg.EAX) {
throw new InvalidProgramException();
}
if (this.Expr.Type.Kind != ExprTypeKind.STRUCT_OR_UNION) {
throw new InvalidProgramException();
}
// size of the struct or union
Int32 struct_size = this.Expr.Type.SizeOf;
// offset inside the pack
Int32 attrib_offset = ((StructOrUnionType)this.Expr.Type)
.Attribs
.First(_ => _.name == this.Name)
.offset;
// can't be a function designator.
switch (this.Type.Kind) {
case ExprTypeKind.ARRAY:
case ExprTypeKind.STRUCT_OR_UNION:
state.ADDL(attrib_offset, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.CHAR:
state.MOVSBL(attrib_offset, Reg.EAX, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.UCHAR:
state.MOVZBL(attrib_offset, Reg.EAX, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.SHORT:
state.MOVSWL(attrib_offset, Reg.EAX, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.USHORT:
state.MOVZWL(attrib_offset, Reg.EAX, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.LONG:
case ExprTypeKind.ULONG:
case ExprTypeKind.POINTER:
state.MOVL(attrib_offset, Reg.EAX, Reg.EAX);
return Reg.EAX;
case ExprTypeKind.FLOAT:
state.FLDS(attrib_offset, Reg.EAX);
return Reg.ST0;
case ExprTypeKind.DOUBLE:
state.FLDL(attrib_offset, Reg.EAX);
return Reg.ST0;
default:
throw new InvalidProgramException();
}
}
