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R01UH0336EJ0102 Rev.1.02
Page 179 of 1538
Jul 17, 2014
V850E2/PG4-L
Section 4 Interrupt Functions
4.4.4
Restore from FE Level Maskable Interrupt (FEINT) Servicing
Restore from FE level maskable interrupt (FEINT) servicing is performed using
the FERET instructions. Execution of the FERET instruction while the PSW.EP
bit status is cleared (0) causes restore processing from the FE level maskable
interrupt (FEINT). 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 FE level maskable interrupts
(FEINT), execute the FERET 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 4-3
Restore from FE Level Maskable Interrupt (FEINT) Servicing
Note
The shaded portions indicate processing which does not branch during
return from servicing of an FE level maskable interrupt (FEINT).
Starts FERET execution
PSW.EP = 0?
Yes
Yes
Yes
Yes
Yes
ICSR.FNE = 1?
ICSR.FIE = 1?
ICSR.EIE = 1?
No
No
No
No
No
ICSR.FIE
0
ICSR.EIE
0
ICSR.FNE
0
PC
FEPC
PSW
FEPSW
The highest currently
set priority level bit
in the ISPR is cleared (to 0).
All bits of ISPR = 0?
Completes FERET
instruction execution