This slide shows how the datapath controlling the R- and I- type ALU instruction execution. The R-type instruction format and example are listed again as follows:
add $t1, $t2, $t3 # $t1 = $t2 + $t3 # rd = rs + rt |
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The following figure shows how to control R-type ALU instructions. The active part of datapath is shown in green.
For R-type ALU instructions, RegDst is ‘1’ to select rd on RW and ALUSrc is ‘0’ to select BusB as the second ALU input.
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The I-type instruction format and example are listed again as follows:
addi $10, $8, 9 # $10 = $8 + 9 # rt = rs + imm16 |
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The following figure shows how to control I-type ALU instructions.
For I-type ALU instructions, RegDst is ‘0’ to select rt on RW and ALUSrc is ‘1’ to select extended immediate as the second ALU input.
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