5-72
Z380
™
U
SER
'
S
M
ANUAL
DC-8297-03
Z
ILOG
IND
INPUT AND DECREMENT (BYTE)
IND
Operation:
(HL)
←
(C)
B
←
B – 1
HL
←
HL – 1
This instruction is used for block input of strings of data. During the I/O transaction the 32-
bit BC register is placed on the address bus. Note that the B register contains the loop count
for this instruction so that A15-A8 are not useable as part of a fixed port address.
First the byte of data from the selected peripheral is loaded into the memory location
addressed by the HL register. Then the B register, used as a counter, is decremented by
one. The HL register is then decremented by one, thus moving the pointer to the next
destination for the input.
Flags:
S:
Unaffected
Z:
Set if the result of decrementing B is zero; cleared otherwise
H:
Unaffected
V:
Unaffected
N:
Set
C:
Unaffected
Addressing
Execute
Mode
Syntax
Instruction Format
Time
Note
IND
11101101 10101010
2+i+w