
118 THE x86 MICROPROCESSORS
INC BX ;second word of the sum
LOOP REPEA ;go back if CX is not 0
MOV DL, 0 ;make DL = 00
ADC DL, 0 ;add the carry to DL
MOV SUMC, DL ;move the carry to SUMC
.EXIT
END
ere are a number of notable features for this program. Let us list out these features.
e double words are stored in two DD locations named LONGNUM1 and LONGNUM2. i)
ey will be stored in the little endian format.
e sum of two double words can be more than a double word. is can be accommodated ii)
as a carry, added to a register, and can be stored in memory as the uppermost byte of the
sum. ree registers are used as pointers ...