Nintendo Ultra64 Programmer's Manual page 175

JALR
31 26 25
SPECIAL
0 0 0 0 0 0
6
Format:
jalr rs 
jalr rd, rs
Description:
The program unconditionally jumps to the address contained in general register
one instruction. The address of the instruction after the delay slot is placed in general register
The default value of
Register specifiers
effect when re-executed. However, an attempt to execute this instruction is
result of executing such an instruction is undefined.
Since instructions must be word-aligned, a Jump and Link Register instruction must specify a
target register (
Since the RSP program counter is only 12 bits, only 12 bits of the calculated address are used.
Operation:
T:
T+1:
Exceptions:
None
Revision 1.0
Jump And Link Register
21 20
rs 0
0 0 0 0 0
5 5
rd
, if omitted in the assembly language instruction, is 31.
rs rd
and may not be equal, because such an instruction does not have the same
rs
) whose two low-order bits are zero.
tempGPR [rs]
GPR[rd]  PC + 8
 temp
PC
11...0 11...0
16 15 11 10
rd 0
0 0 0 0 0
5 5
JALR
6 5 0
JALR
0 0 1 0 0 1
6
rs
, with a delay of
not
trapped, and the
rd
.
175