DAA

DAA

Decimal Adjust Accumulator

Description

Does cool stuff with binary-coded decimal.

Uses

• Probably useful for BCD arithmetic?

Results

Register/Flag	8-bit
S flag	Set to the 7th bit of the result
Z flag	Set if the result is 0; else reset
H flag	Really complicated
P/V flag	Set if the result has even parity; else reset
N flag	Not affected
C flag	Really complicated

Allowed Instructions

Instruction	Opcode	CC (ADL/non-ADL)	CC (.S)	CC (.L)
daa	$27	1F	X	X

Notes

• When using CP with signed integers, the flags are set as follows:

  • Z means M = N
  • NZ means M ≠ N
  • C means M < N
  • NC means M ≥ N

See Also

ADD, ADC, RLD, RRD, SBC, SUB