R-type

R-Format Instruction Layout

  • opcode: partially specifies what instruction it is

    • Note: This field is equal to 0110011 for all R-format register-register arithmetic instructions

  • funct7 + funct3: combined with opcode, these two fields describe what operation to perform

  • rs1(Source Register #1): specifies register containing first operand

  • rs2: specifies second register operand

  • rd(Destination Register): specifies register which will receive result of computation

Each register field holds a 5-bit unsigned integer (0-31) corresponding to a register number (x0-x31)

R-Format Instructions

Decoding funct7 and funct3 fields to select appropriate ALU functions.

Datapath

Here is our datapath for R-format instructions.

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