"move.w (%%a0),%%d0             \n\t"
		"move.b (%%a1),%%d2             \n\t"
		"add.l  %%d2,%%d0               \n\t"
		"cmp.l   #255,%%d0              \n\t"  /* overflow? */
        "bls.b   1f          			\n\t"  /* no: return value */
        "spl.b   %%d0					\n\t"  /* yes: set low byte to appropriate boundary */
    	"1	:                    		\n\t"
		"move.b %%d0,(%%a1)			    \n\t"