Nintendo GAME BOY Programming Manual page 103

Examples: When A = E1h, E = 0Fh, (HL) = 1Eh, and CY = 1,
ADC A, E ; A ← F1h, Z ← 0, H ← 1, CY ← 0
ADC A, 3Bh ; A ← 1Dh, Z ← 0, H ← 0, CY ← -1
ADC A, (HL) ; A ← 00h, Z ← 1, H ← 1, CY ← 1
SUB
Subtracts the contents of operand s from the contents of register A and stores the results in register A.
r, n, and (HL) are used for operand s.
Flag Z: Set if result is 0; otherwise reset.
H: Set if there is a borrow from bit 4; otherwise reset.
N: Set
CY: Set if there is a borrow; otherwise reset.
Examples: When A = 3Eh, E = 3Eh, and (HL) = 40h,
SUB E
SUB 0Fh ;
SUB (HL) ;
SBC A,
Subtracts the contents of operand s and CY from the contents of register A and stores the results in
register A.
r, n, and (HL) are used for operand s.
ADC A, r
ADC A, n
ADC A, (HL)
A ← A-s
s
SUB r
SUB n
SUB (HL)
A ← 00h, Z ← 1, H ← 0, N ← 1 CY ← 0
;
A ← 2Fh, Z ← 0, H ← 1, N ← 1 CY← 0
A ← FEh, Z ← 0, H ← 0, N ← 1 CY ← 1
A ← A-s-CY
s
CYCL 7 6 5 4 3 2
1 10 001
2 11 001 110
n
2 10 001 110
CY H
* * 1
CYCL 7 6 5 4 3 2
1 10 010
2 11 010 110
n
10 010 110
2
CY H
* * 1
103
Chapter 4: CPU Instruction Set
1 0
r
N Z CYCL 7 6 5 4 3
* -- --
1 0
r
N Z CYCL 7 6 5 4 3
* -- --
2 1 0
-- --
2 1 0
-- --