Immediate Value Generation Unit
Instructions with immediate values can be categorized into 4 groups and I-Type instructions can be further categorized into 3 sub groups.
- U type Immediate
- J type Immediate
- S type Immediate
- B type Immediate
- I type Immediate with signed Extension (Extend with sign bit)
- I type immediate containing shift amount
- I type immediate with unsigned Extension (Extend with Zero)
Inputs to the immediate value generation unit are,
- INSTRUCTION[31:7]
- IMM_SEL control signal[2:0]
Output of the immediate value generation unit is,
- IMMEDIATE_VALUE[31:0]
Immediate value generation unit will generate the immediate values and sign extends by rerouting the wires. Depending on the IMM_SEL control signal, this unit will output the proper immediate value. Immediate value generation and sign extending of the 7 categories are shown in the figure below.
