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CHAPTER 9 REGISTER FILE (RF)
74
Figure 9-3 shows an example of register file operation.
As shown in Figure 9-3, reading and writing of data to and from the control register (address locations 00H to 3FH)
is performed using the "PEEK WR, rf" and "POKE rf, WR" instructions. Data within the control register specified using
rf can be read from and written to the control register, only by using these instructions with the window register.
The fact that the register file overlaps with data memory in addresses 40H to 7FH has the following effect: When
a "PEEK WR, rf" or "POKE rf, WR" instruction is executed, the effect is the same as if they were being executed on
the data memory address (in the current bank) specified by rf.
Addresses 40H to 7FH of the register file can be operated by normal memory manipulation instructions.
Control registers can be manipulated in 1-bit unit by using built-in macro instruction.
Figure 9-3. Accessing the Register File Using the PEEK and POKE Instructions
0
1
2
3
4
5
6
7
0
System register
<6> ST
Column address
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Data memory
<2> LD M030, WR
<3> POKE RF73, WR
<4> PEEK WR, RF70
BANK0
0
1
2
3
Row address
<1> PEEK WR, RF11
<5> POKE RF33, WR
Control register
WR, M032
WR
Register file
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