The immediate is sign extended, but both rs and the extended immediate are treated as unsigned integers. They can be used in combination with beq and bne and $zero to branch based on the comparison of two registers. These instructions set rd to 1 if their condition is true. Instruction:īranch if rs is less than zero. Instruction:īranch if rs is greater than zero. Instruction:īranch if rs is less than or equal to zero. Instruction:īranch if rs is greater than or equal to zero. Instruction:īranch if rs and rt are not equal. Instruction:īranch if rs and rt are equal.
MIPS IFORMAT PC
Instead of using rt as a destination operand, rs and rt are both used as source operands and the immediate is sign extended and added to the PC to calculate the address of the instruction to jump to if the branch is taken. We can call the subroutine using the following line: jal MySubĪnd we can define MySub as follows to return to the main body of the parent routine: jr $ra Let's say that we have a subroutine that starts with the label MySub. The same as the jr instruction, except that the return address is loaded into a specified register (or $ra if not specified) Like the j instruction, except that the return address is loaded into the $ra register. To return to the main body routine after completion. Jump and Link instructions are similar to the jump instructions, except that they store the address of the next instruction (the one immediately after the jump) in the return address ($ra $31) register.
As such, the jr instruction can be called as such: jr $t0Īssuming the target jump location is located in $t0. The jr instruction loads the PC register with a value stored in a register. This immediate value is either a numeric offset or a label (and the assembler converts the label into an offset). The j instruction loads an immediate value into the PC register. This causes the next instruction read from memory to be retrieved from a new location. The jump instructions load a new value into the PC register, which stores the value of the instruction being executed.
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