Daa - Hitachi H8/300H Series Programming Manual

2.2.23 DAA

DAA (Decimal Adjust Add)
Operation
Rd (decimal adjust) → Rd
Assembly-Language Format
DAA Rd
Operand Size
Byte
Description
Given that the result of an addition operation performed by an ADD.B or ADDX instruction on
4-bit BCD data is contained in an 8-bit register Rd (destination register) and the carry and half-
carry flags, the DAA instruction adjusts the general register contents by adding H'00, H'06, H'60,
or H'66 according to the table below.
C Flag Upper 4 Bits
before before
Adjustment Adjustment
0
0
0
0 A to F
0 9 to F
0 A to F
1
1
1
H Flag
before
Adjustment
0 to 9 0
0 to 8 0
0 to 9 1
0
0
1
1 to 2 0
1 to 2 0
1 to 3 1
Condition Code
I UI H
— — *
H: Undetermined (no guaranteed value).
N: Set to 1 if the adjusted result is negative;
otherwise cleared to 0.
Z: Set to 1 if the adjusted result is zero;
otherwise cleared to 0.
V: Undetermined (no guaranteed value).
C: Set to 1 if there is a carry at bit 7;
otherwise left unchanged.
Lower 4 Bits
Value Added
before
(hexadecimal)
Adjustment
0 to 9
A to F
0 to 3
0 to 9
A to F
0 to 3
0 to 9
A to F
0 to 3
75
Decimal Adjust
U N Z V C
— *
C Flag
after
Adjustment
00 0
06 0
06 0
60 1
66 1
66 1
60 1
66 1
66 1