TITLE Extended Addition  (extadd.asm)

.686
.MODEL flat, stdcall
.STACK 4096

INCLUDE Irvine32.inc

.data
var1   DWORD    0FFFFFFFFh, 0FFFFFFFFh, 0FFFFFFFFh, 1
var2   DWORD    1, 0, 0, 0

.code
main PROC
    mov EDI, OFFSET var1
    mov ESI, OFFSET var2
    mov ECX, LENGTHOF var1
    call extadd
    exit
main ENDP




; Adds two 64-bit numbers
; Receives: EBX:EAX = first 64-bit number
;           EDX:ECX = second 64-bit number
; Returns:  result is in EBX:EAX
;           arithmetic flags are set

add64 PROC
    add EAX, ECX
    adc EBX, EDX
    ret
add64 ENDP



; Extended multiword addition of arrays of double words
; First array element is the least significant double word
; Last  array element is the most  significant doubleword
; Addition should proceed from the first to the last array element
; Receives: EDI = address of destination operand
;           ESI = address of source operand
;           ECX = count of DWORD in extended integer
; Returns:  Result is stored in destination array

extadd PROC
; Complete the writing of this procedure
extadd ENDP

END main