SAB80515 Datasheet, PDF (154/270 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller Family

Instruction Set
Operation:
BCD variables can be incremented or decremented by adding 01H or 99H. If the
accumulator initially holds 30H (representing the digits of 30 decimal), then the
instruction sequence
ADD
DA
A, #99H
A
will leave the carry set and 29H in the accumulator, since 30 + 99 = 129. The low-
order byte of the sum can be interpreted to mean 30 – 1 = 29.
DA
contents of accumulator are BCD
if [[(A3-0) > 9] ∨ [(AC) = 1]]
then (A3-0) ← (A3-0) + 6
and
if [[(A7-4) > 9] ∨ [(C) = 1]]
then (A7-4) ← (A7-4) + 6
Encoding:
Bytes:
Cycles:
1101 0100
1
1
Semiconductor Group
154