Filter
Top Products
Architecture
171
RFE Restore From Exception RFE
31 26 25 24 6 5 0
COP0
010000
CO
1
0
000 0000 0000 0000 0000
RFE
010000
6 1 19 6
Format :
RFE
Description :
Copies the Status register bits for previous interrupt mask mode and previous kernel/user mode
(IEp and KUp) to the current mode bits (IEc and KUc), and copies the old mode bits (IEo and KUo)
to the previous mode bits (IEp and KUp). The old mode bits remain unchanged.
Similarly, it copies the Cache register bits for previous data cache auto-lock mode and previous
instruction cache auto-lock mode (DALp and IALp) to the current mode bits (DALc and IALc), and
copies the old mode bits (DALo and IALo) to the previous mode bits (DALp and IALp). The old
mode bits remain unchanged.
Normally an RFE instruction is placed in the delay slot after a JR instruction in order to restore the
PC.
Operation :
T:
Status ← Status
31..4
|| Status
5..2
Cache ← 0
8
|| Cache
13..12
|| Cache
13..0
|| 0
8
Exceptions :
Coprocessor Unusable exception