Format Of Stack Pointer And Stack Bank Select Register; Data Saved To The Stack Memory (Mk I Mode) - NEC PD750004 User Manual

Figure 4-11. Format of Stack Pointer and Stack Bank Select Register
Address
F80H
F84H
SBS
Note The Mk I mode and Mk II mode can be switched by bit 3 of SBS. The stack bank selection function
can be used in both Mk I mode and Mk II mode. (See Section 4.1 for details.)
Example SP initialization
Specify memory bank 1 as a stack area to start stack operation at address 1FFH.
SEL MB15
MOV A,#1
MOV SBS,A
MOV XA,#00H
MOV SP,XA
Figure 4-12. Data Saved to the Stack Memory (Mk I Mode)
PUSH instruction
Stack
SP – 2
Lower bits of pair register
SP – 1
Upper bits of pair register
SP
Note PC12 and PC13 are 0 in the µPD750004. PC13 is 0 in the µPD750006 and µPD750008.
SP7 SP6 SP5
000H
0FFH
100H
1FFH
; or CLR1 MBE
; Specify memory bank 1 as a stack area
; SP <– 00H
CALL or CALLF instruction
SP – 4
SP – 3
MBE
SP – 2
SP – 1
SP
CHAPTER 4 INTERNAL CPU FUNCTIONS
SP4 SP3 SP2
Note
SBS3 0 SBS1
Memory bank 0
Memory bank 1
Stack
PC11 - PC8
Note Note
RBE PC13 PC12
PC3 - PC0
PC7 - PC4
Symbol
SP1 0 SP
SBS0 SBS
SP
SP
Interrupt
Stack
SP – 6 PC11 - PC8
SP – 5
MBE RBE
SP – 4 PC3 - PC0
SP – 3 PC7 - PC4
SP – 2 IST1 IST0
PSW
SP – 1 CY SK2
SP
Note Note
PC13 PC12
MBE RBE
SK1 SK0
5 9