Returning a struct from a function is not working as expected

[zu2]

Returning a struct from a function is not working as expected. I thought that if the return value is 4 bytes or less, it would be returned as an int or long, but only 2 bytes are being returned.

struct complex {
    int r;
    int i;
};

struct complex sub() {
    struct complex com_1;

    com_1.r = 1234;
    com_1.i = 5678;

    return com_1;
}

_sub:
	des
	des
	des
	des
	ldab #$D2
	ldaa #$04
	jsr storetos
	ldab #$2E
	ldaa #$16
	staa $02,x
	stab $02+1,x
	ldaa $00,x
	ldab $00+1,x
L00DA:
	ins
	ins
	ins
	ins
	rts