NEC uPD98502 User Manual page 501

JR
31 26 25
SPECIAL
0 0 0 0 0 0
6
Format:
JR rs
Description:
The program unconditionally jumps to the address contained in general register rs , with a delay of one instruction.
When a MIPS16 instruction can be executed, the program unconditionally jumps with a delay of one instruction to
the address indicated by the value of clearing the least significant bit of the general register rs to 0. Then, the
content of the least significant bit of the general register rs is set to the ISA mode bit (internal).
Since 32-bit length instructions must be word-aligned, a JR instruction must specify a target register ( rs ) that
contains an address whose two low-order bits are zero when a MIPS16 instruction can be executed. If these low-
order bits are not zero, an address error exception will occur when the jump target instruction is subsequently
fetched.
Operation:
temp ← GPR [rs]
32, 64 T:
T+1:
If MIPS16EN = 1 then
PC ← temp
ISA MODE ← temp
else
PC ← temp
endif
Exceptions:
None
APPENDIX A MIPS III INSTRUCTION SET DETAILS
Jump Register
21 20
rs
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
5
|| 0
63..1
0
Preliminary User's Manual S15543EJ1V0UM
6 5
0
15
JR
0
JR
0 0 1 0 0 0
6
501