Zilog Z80380 - Manual (Page 135)

5-101
Z380 ™
U SER ' S M ANUAL Z ILOG
DC-8297-03
LDIW
LOAD AND INCREMENT (WORD)
LDIW
Operation: if (LW) then begin
(DE)
←
(HL)
(DE+1)
←
(HL+1)
(DE+2)
←
(HL+2)
(DE+3)
←
(HL+3)
DE
←
DE + 4
HL
←
HL + 4
BC(15-0)
←
BC(15-0) – 4
end
else begin
(DE)
←
(HL)
(DE+1)
←
(HL+1)
DE
←
DE + 2
HL
←
HL + 2
BC(15-0)
←
BC(15-0) – 2
end
This instruction is used for block transfers of words of data. The word of data at the location
addressed by the HL register is loaded into the location addressed by the DE register. Both
the DE and HL registers are then incremented by two or four, thus moving the pointers to
the succeeding words in the array. The BC register, used as a byte counter, is then
decremented by two or four.
Both DE and HL should be even, to allow word transfers on the bus. BC must be even,
transferring an even number of bytes, or the operation is undefined.
Flags: S: Unaffected
Z: Unaffected
H: Cleared
V: Set if the result of decrementing BC is not equal to zero; cleared otherwise
N: Cleared
C: Unaffected
Addressing Execute
Mode Syntax Instruction Format Time Note
LDIW 11101101 11100000 3+r+w L