Z8 Register Addressing (R) - ZiLOG Z8 User Manual

Z8 Microcontrollers
Addressing Modes

11.2 Z8 REGISTER ADDRESSING (R)

In 8-bit Register Addressing mode, the operand value is equiva-
lent to the contents of the specified register or register pair.
8-Bit Register
File Address
One Operand
Instruction
(Example)
In 4-bit Register Addressing (Figure 11-2), the destination
and/or source addresses point to the Working Register within the
current Working Register Group. This 4-bit address is combined
4-Bit Working
Registers
Two Operand
Instruction
(Example)
11-2
Program Memory
dst
OpCode
Figure 11-1. 8-Bit Register Addressing
Program Memory
dst src
Points to
One Register
Op Code
in the
Register
File
Figure 11-2. 4-Bit Register Addressing
In the Register Addressing (Figure 11-1), the destination and/or
source address specified corresponds to the actual register in the
register file.
Register File
Operand
Points to
One Register
in the
Register
File
with the upper four bits of the Register Pointer to form the actual
8-bit address of the affected register.
Register File
RP
Operand
Operand
ZiLOG
Points to
Origin of
Working
Register
Group
UM001601-0803