Zilog Z08470 User Manual
Page 166
Z80 Instruction Set
UM008007-0715
154
Z80 CPU
User Manual
r identifies registers B, C, D, E, H, L, or A assembled as follows in the object code field:
Description
The s operand, along with the Carry flag (C in the F Register) is subtracted from the con-
tents of the Accumulator, and the result is stored in the Accumulator.
Condition Bits Affected
S is set if result is negative; otherwise, it is reset.
Z is set if result is 0; otherwise, it is reset.
H is set if borrow from bit 4; otherwise, it is reset.
P/V is reset if overflow; otherwise, it is reset.
N is set.
C is set if borrow; otherwise, it is reset.
Example
If the Accumulator contains
16h
, the carry flag is set, the HL register pair contains
3433h
,
and address
3433h
contains
05h
, then upon the execution of an SBC A, (HL) instruction,
the Accumulator contains
10h
.
Register
r
B
000
C
001
D
010
E
011
H
100
L
101
A
111
Instruction
M Cycles
T States
4 MHz E.T.
SBC A, r
1
4
1.00
SBC A, n
2
7(4, 3)
1.75
SBC A, (HL)
2
7 (4, 3)
1.75
SBC A, (IX+d)
5
19 (4, 4, 3, 5, 3)
4.75
SBC A, (lY+d)
5
19 (4, 4, 3, 5, 3)
4.75