; naive solution AREA myadd, CODE, READONLY EXPORT add_64 add_64 ; get low words LDR a4,[a2,#0] LDR ip,[a3,#0] ; add low words + set carry ADDS a4,a4,ip ; store low word result STR a4,[a1,#0] ; get high words LDR a2,[a2,#4] LDR a3,[a3,#4] ; add with carry adcs a2,a2,a3 ; store result STR a2,[a1,#4] ; return state of carry flag MOV a1, #0 adc a1, a1, #0 MOV pc,lr END