The X 86 Microprocessors: Architecture, Programming and Interfacing (8086 to Pentium) 2nd Edition by Pearson

3-26

THE

x86 MICROPROCESSORS

ADC DL, 0 ;add the carry to DL

MOV SUMC, DL ;move the carry to SUMC

.EXIT

END

There are a number of notable features for this program. Let us list out these features.

i) The double words are stored in two DD locations named LONGNUM1 and

LONGNUM2. They will be stored in the little endian format.

ii) The sum of two double words can be more than a double word. This can be accom-

modated as a carry, added to a register and can be stored in memory as the upper-

most byte of the sum. Three registers are used as pointers to each double word.

However, addition can be done only as words, as the maximum size of an operand ...