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R01UH0336EJ0102 Rev.1.02
Page 182 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 4 Interrupt Functions
4.4.6
Restore from EI Level Maskable Interrupt (EIINT)
Restore from EI level maskable interrupt (EIINT) is performed using the EIRET
instruction. Execution of the EIRET instruction while the PSW.EP bit status is
cleared (0) causes restore processing from the interrupt. Completely restoring
from interrupt servicing when the PSW.EP bit is "1" is not possible (clearing of
the ICSR, ISPR, and other registers is not performed). For return from EI level
maskable interrupt, execute the EIRET instruction with the PSW.EP bit always
cleared (0).
Caution
Although this CPU core incorporates an RETI instruction, this is only provided
for backward compatibility with the V850E1 and V850E2 architectures and its
use is, in principle, prohibited.
Replace all RETI instructions other than existing programs that cannot be
modified with EIRET or FERET instructions.
Figure 4-5
Restore from EI Level Maskable Interrupt (EIINT)
Note
The shaded portions indicate processing which does not branch during
return from servicing of an EI level maskable interrupt (EIINT).
Starts EIRET execution
Completes EIRET
instruction execution
No
Yes
No
Yes
No
Yes
No
No
Yes
Yes
PSW.EP = 0?
ICSR.EIE
0
ICSR.FNE 0
ICSR.FIE
0
The highest currently
set priority level bit in
the ISPR is cleared (to 0)
ICSR.FNE = 1?
ICSR.FIE = 1?
ICSR.EIE = 1?
All bits of ISPR = 0?
PC
PSW
EIPC
EIPSW