Register Convention
Under the register convention, up to three parameters are passed in CPU registers, and the rest (if any) are passed
on the stack. The parameters are passed in order of declaration (as with the pascal convention), and the first three
parameters that qualify are passed in the EAX, EDX, and ECX registers, in that order. Real, method-pointer, variant,
Int64, and structured types do not qualify as register parameters, but all other parameters do. If more than three
parameters qualify as register parameters, the first three are passed in EAX, EDX, and ECX, and the remaining
parameters are pushed onto the stack in order of declaration. For example, given the declaration
procedure Test(A: Integer; var B: Char; C: Double; const D: string; E: Pointer);
a call to Test passes A in EAX as a 32-bit integer, B in EDX as a pointer to a Char, and D in ECX as a pointer to a
long-string memory block; C and E are pushed onto the stack as two double-words and a 32-bit pointer, in that order.
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