MIPS I-Type Instruction

Abstract

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• I because it is Instruction that contains Immediate Value
• 4 parts - Opcode, Source Register, Target Register & Immediate Value
• Meaning: Add the Source Register with the Immediate Value, and store the result to the Target Register

Examples

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andi

• Perform a bitwise AND operation between a register and an immediate value
• Get last 4 significant Bit of $s0,andstoreitinside$t0 - andi $t0, $s0 , 0xF

slti

• Set Less Than Immediate
• If value in Source Register is smaller than Immediate Value, then Target Register is set to 1 else 0
• The mips code - slti $t0, $t0, 100
• The equivalent more high-level code - R[rt] = (R[rs]<SignExtImm) ? 1 : 0

bne

• Branch if Not Equal

Terminologies

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Immediate Value

• Value is 2’s Complement (补码)
• 16-bits, can represent up to +-2^15 Word, 2^17 Memory Address because 4-bytes Word Addressing
• Used for PC-Relative Addressing