User's Manual

THE 80286 INSTRUCTION SET
AAD - ASCII Adjust AX Before Division
Opcode
Instruction Clocks
Description
05 OA AAO 14
ASCII adjust AX before division
FLAGS MODIFIED
Sign, zero, parity
FLAGS UNDEFINED
Overflow, auxiliary carry, carry
OPERATION
AAD is used to prepare two unpacked BCD digits (least significant in AL, most significant in AH) for
a division operation which will yield an unpacked result. This
is accomplished by setting AL to AL +
(10 X AH), and then setting AH to O. This leaves AX equal to the binary equivalent of the original
unpacked 2-digit number.
PROTECTED MODE EXCEPTIONS
None
REAL ADDRESS MODE EXCEPTIONS
None
8-16