MIPS R-Type Instruction

Abstract

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• Opcode is always 000000
• Operation is decided by the Function Code
• 6 parts - Opcode, Source Register, Target Register, Destination Register, Shift Amount & Function Code

Examples

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srl

• Shift Right Logical
• Source Register is 0
• Shifts the value right by n bits, discarding the lower n bits
• Dividing the value in register $s0 by 16 (2^4) - srl $s0, $s0, 4

Terminologies

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Destination Register

• 5bits
• Labeled rd, mapped to WR
• Register that gets the result of Operation in MIPS R-Type Instruction Instruction

Function Code

• 6 bits
• Give MIPS (2^6-1) + 2^6 = 127 instead of 2^6=64 Instruction
• Dedicated for MIPS R-Type Instruction (if my understanding isn’t wrong)

Shift Amount

• 5bits
• Labeled as shamt