Zilog Z80380 - Manual (Page 107)

5-73
Z380 ™
U SER ' S M ANUAL Z ILOG
DC-8297-03
INDW
INPUT AND DECREMENT (WORD)
INDW
Operation: (HL)
←
(DE)
BC(15-0)
←
BC(15-0) – 1
HL
←
HL – 2
This instruction is used for block input of strings of data. During the I/O transaction the 32-
bit DE register is placed on the address bus.
First the word of data from the selected peripheral is loaded into the memory location
addressed by the HL register. Then the BC register, used as a counter, is decremented by
one. The HL register is then decremented by two, thus moving the pointer to the next
destination for the input.
Flags: S: Unaffected
Z: Set if the result of decrementing BC is zero; cleared otherwise
H: Unaffected
V: Unaffected
N: Set
C: Unaffected
Addressing Execute
Mode Syntax Instruction Format Time Note
INDW 11101101 11101010 2+i+w