Zilog Z86193 - Manual (Page 16)

Z8
®
CPU
User Manual
UM001604-0108 Address Space
9
Figure 4. Working Register Addressing Examples
*Note: The full register file is shown. Refer to the selected device product specification for actual file
size.
Figure 5. Register Pointer
0 1 1 1 0 1 1 0
Register Pointer (FDh), Standard Register File 0 1 1 1 0 0 0 0
1 1 0 1 1 1 1 1 INC R6 (instruction, short format)
Actual register address (76h)
FF
F0
R7 R6 R5 R4 R3 R2 R1 R0
Specified Working Register Group
R253
I/O Ports
Working Register Group 1
Working Register Group 0
Working Register Group F
EF
80
7F
70
6F
60
5F
50
4F
40
3F
30
2F
20
1F
10
0F
00
The lower nibble
of the register
file address
(provided by the
instruction) points
to the specified
register.
The upper nibble of the register file address,
provided by the register pointer, specifies
the active working-register group.
(Register Pointer)
R15 to R0
R15 to R4
R3 to R0