R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 68

• Manufacturer Part Number: R5F21133DFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES
• Manufacturer: RENESAS [Renesas Technology Corp]

R8C/13 Group
Rev.1.20
REJ09B0111-0120
Figure 10.6 Stack Status Before and After Acceptance of Interrupt Request
Figure 10.7 Operation of Saving Register
Address
• Saving Registers
m – 4
m – 3
m – 2
m – 1
m + 1
Stack status before interrupt request
is acknowledged
Jan 27, 2006
m
In the interrupt sequence, the FLG register and PC are saved to the stack.
At this time, the 4 high-order bits in the PC and the 4 high-order (IPL) and 8 low-order bits in the FLG
register, 16 bits in total, are saved to the stack first. Next, the 16 low-order bits in the PC are saved.
Figure 10.6 shows the stack status before and after an interrupt request is accepted.
The other necessary registers must be saved in a program at the beginning of the interrupt routine.
The PUSHM instruction can save several registers in the register bank being currently used
single instruction .
NOTES:
1. Selectable from registers R0, R1, R2, R3, A0, A1, SB, and FB.
The registers are saved in four steps, 8 bits at a time. Figure 10.7 shows the operation of the saving
registers.
NOTES:
1. When any INT instruction in software numbers 32 to 63 has been executed, this is the SP indi-
MSB
cated by the U flag. Otherwise, it is the ISP.
Content of previous stack
Content of previous stack
Stack
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Address
[ S P ] – 5
[SP] – 4
[ S P ] – 3
[ S P ] – 2
[ S P ] – 1
[ S P ]
N O T E S :
1 . [ S P ] d e n o t e s t h e i n i t i a l v a l u e o f t h e S P w h e n i n t e r r u p t r e q u e s t i s a c k n o w l e d g e d .
A f t e r r e g i s t e r s a r e s a v e d , t h e S P c o n t e n t i s [ S P ] m i n u s 4 .
LSB
[SP]
SPvalue before
interrupt occurs
F L G
H
Stack
F L G
P C
P C
M
L
L
PC
H
Address
m – 4
m – 3
m – 2
m – 1
m
m + 1
Stack status after interrupt request
is acknowledged
MSB
S e q u e n c e i n w h i c h o r d e r
r e g i s t e r s a r e s a v e d
( 3 )
( 4 )
( 1 )
( 2 )
F i n i s h e d s a v i n g r e g i s t e r s
i n f o u r o p e r a t i o n s .
Content of previous stack
Content of previous stack
FLG
Saved, 8 bits at a time
H
Stack
PC
PC
FLG
L
M
L
PC
H
LSB
10.1 Interrupt Overview
[SP]
New SP value
(1)
with a