Z8 Microcontrollers
Instruction Descriptions and Formats ZiLOG
12-44 UM001601-0803
LDEI
LOAD EXTERNAL DATA AUTO-INCREMENT
LDEI
Load External Data Auto-increment
LDEI dst, src
Instruction Format:
Operation:
dst <— src
r <— r + 1
rr <— rr + 1
This instruction is used for block transfers of data between external data memory and the Register File. The address
of the external data memory location is specified by a Working Register Pair, and the address of the Register File
location is specified by a Working Register. The contents of the source location are loaded into the destination
location. Both addresses in the Working Registers are then incremented automatically. The contents of the source
are not affected.
Example:
If Working Register Pair R6 and R7 contains 404AH, external data memory location 404AH and 404BH contain
ABH and C3H respectively, and Working Register R2 contains 22H, the statement:
LDEI @R2, @RR6
Op Code: 83 26
loads the value ABH into Register 22H. Working Register Pair RR6 is incremented to 404BH and Working Register
R2 is incremented to 23H. A second
LDEI @R2, @RR6
Op Code: 83 26
loads the value C3H into Register 23H. Working Register Pair RR6 is incremented to 404CH and Working Register
R2 is incremented to 24H.
Cycles
OPC
Address Mode
(Hex)
dst src
18 93 Irr Ir
18 83 Ir Irr
OPC
OPC
dst src
src dst
Flags: C: Unaffected
Z: Unaffected
S: Unaffected
V: Unaffected
D: Unaffected
H: Unaffected
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