Epson 6200A - Manual (Page 12)

6 EPSON S1C6200/6200A CORE CPU MANUAL
2 MEMORY AND OPERATIONS
2.1.6 PSET instruction
Jump or call instructions must follow PSET immediately in order for PSET to affect the destination address.
When a jump or call is not immediately preceded by PSET, the destination address is within the current
page.
Some examples using PSET are shown in Table 2.1.6.1.
Table 2.1.6.1 PSET examples
Operation
The program jumps to bank 1, page 3, step 8.
The data set by PSET is canceled.
The program jumps to bank 0, page 1, step 9.
C flag is set.
The program jumps to bank 1, page 4, step 7 because C flag = 1.
C flag is reset.
No jump occurs because C flag = 0.
The data set by PSET is canceled, and the program jumps to bank 0, page 1, step 9.
Bank Page Stap Instruction
PSET
JP
PSET
NOP5
JP
SCF
PSET
JP
RFC
PSET
JP
JP
13H
08H
15H
09H
14H
C, 07H
05H
C, 08H
09H
0
0
•
•
0
0
0
•
•
0
0
0
•
•
0
0
0
0
•
•
01H
01H
•
•
01H
01H
01H
•
•
01H
01H
01H
•
•
01H
01H
01H
01H
•
•
10H
11H
•
•
21H
22H
23H
•
•
55H
56H
57H
•
•
60H
61H
62H
63H
•
•
•
•
•
•
•
•
•
•
2.1.7 CALZ instruction
CALZ is a direct subroutine call instruction. It calls a subroutine, in page 0 of the current bank, from any
page without requiring the use of PSET.
If CALZ is executed immediately after PSET, the bank and page set by PSET is canceled. This allows direct
subroutine calls to page 0, minimizing repeated code and unnecessary use of PSET. See Figure 2.1.7.1.
Fig. 2.1.7.1 The use of the CALZ instruction
Bank 0 Page 0
EEE....................
RET
Bank 0 Page 2
PSET
CALZ
LD
Not effect
on destination
of CALZ 0AH
EEE
A,0