CHAPTER 7 SYSTEM REGISTER (SYSREG)
56
Example 2. Indirect data transfer using the general register
Assume that the general register is row address 0.
R005
MEM
0.05H
M034
MEM
0.34H
MOV
IXL, #0001B
;
IX
←
00000000001B
MOV
IXM, #0000B
;
MOV
IXH, #0000B
;
MPE
←
0
OR
PSW, #.DF.IXE AND 0FH ;
IXE
←
1
MOV
R005, #8
;
R005
←
8
MOV
@R005, M034
;
Indirect data transfer using the
register
As shown in Figure 7-12, when the above instructions are executed, the contents of data
memory address 35H is transferred to data memory location 38H.
When the MOV @r, m instruction is executed when IXE=1, the data memory address
specified by m (direct address) is modified using the contents of the index register. The bank
and row address of the indirect address specified by @r are also modified using the index
register.
The bank, row address, and column address specified by m (direct address) are all modified,
and the bank and row address specified by @r (indirect address) are modified. Therefore,
in the above example the direct address is 35H and the indirect address is 38H. This example
is different from
Example 3
in
7.5.3
when IXE=0 for the following reasons: In this example,
the bank, row address and column address of the direct address specified by m are modified
using the index register. The general register is transferred to the address specified by the
column address of the modified data memory address and the same row address. (In
Example 3
in
7.5.3
the direct address is not modified.)
Summary of Contents for mPD17120 Subseries
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