TSK3000A Core Instruction - JALR

Instruction:

Jump And Link Register

Assembler Format:

jalr rA

Example:

jalr $4
jalr $30, $4

Description:

Description: Causes the program to jump unconditionally to the address in GPR rA after a delay of one instruction cycle. The address of the instruction following the delay slot is put in GPR rC as the return address from the jump. If rC is omitted from the assembly language instruction, the address stored in general purpose register r31 is used as the default value.
rA and rC must not be equal, since such an instruction would not have the same result if re-executed. This error is not trapped, however the result is undefined.

Since instructions must be aligned on a word boundary, the two low-order bits of the value in target register rA must be 00.

Operation:

rC <-- PC + 8
PC <-- rA

Instruction Type:

R-Type

Instruction Fields:

rA = Index of register containing jump address

rC = Index of register containing return address