This repository is meant to provide a C implementation of a 32-bit assembly instruction encoder for MIPS processors. The program is indeed able to encode in machine code a set of assembly instructions reading the input data from the "input.txt" file and printing the result into the "output.txt" file.
The MIPS instruction subset is described in the following table:
| Instruction | Syntax | Operation | Description |
|---|---|---|---|
| add | add $R1 $R2 $R3 | $R1 = $R2 + $R3 | Addition with overflow |
| sub | sub $R1 $R2 $R3 | $R1 = $R2 - $R3 | Subtraction with overflow |
| and | and $R1 $R2 $R3 | $R1 = $R2 & $R3 | Bitwise and |
| or | or $R1 $R2 $R3 | $R1 = $R2 | $R3 | Bitwise or |
| nor | nor $R1 $R2 $R3 | $R1 = ~($R2 | $R3) | Bitwise nor |
| xor | xor $R1 $R2 $R3 | $R1 = $R2 ^ $R3 | Bitwise xor |
| addi | addi $R1 $R2 i | $R1 = $R2 + SE(i) | Addition immediate with overflow |
| andi | andi $R1 $R2 i | $R1 = $R2 + ZE(i) | Bitwise and immediate |
| ori | ori $R1 $R2 i | $R1 = $R2 + ZE(i) | Bitwise or immediate |
| sll | sll $R1 $R2 a | $R1 = $R2 << a | Shift left logical |
| srl | srl $R1 $R2 a | $R1 = $R2 >> a | Shift right logical |
| slt | slt $R1 $R2 $R3 | $R1 = ($R2 < $R3) | Set if less than |
| slti | slti $R1 $R2 i | $R1 = ($R2 < SE(i)) | Set if less than immediate |
| lw | lw $R1 i $R2 | $R1 = MEM[ $R2 + i]:4 | Load word |
| sw | sw $R1 i $R2 | MEM[ $R2 + i]:4 = $R1 | Store word |
| j | j i | pc += i << 2 | Jump |
| beq | beq $R1 $R2 i | if ($R1 == $R2) pc += i << 2 | Branch equal to |
| bne | bne $R1 $R2 i | if ($R1 != $R2) pc += i << 2 | Branch not equal to |
The command to compile the C source file with GCC is:
$ gcc -Wall -o <output_binary> MIPS32_encoder.cThe compiled executable file will be saved as <output_binary> (e.g., MIPS32_encoder) in your current working directory, then you can run the program as follows:
$ MIPS32_encoder <input_file.ext> <output_file.ext>where the <input_file.ext> contains a sequence of assembly instructions and the <output_file.ext> contains the encoded machine code.
Below you can find an example of an input file containing a few assembly instructions and the resulting conversion in the output file.
input.txt
addi $R1 $R0 30
sw $R1 0 $R0
lw $R3 0 $R0output.txt
-- auto generated
-- addi $R1,$R0,30
0 => "00100000",
1 => "00000001",
2 => "00000000",
3 => "00011110",
-- sw $R1,0($R0)
4 => "10101100",
5 => "00000001",
6 => "00000000",
7 => "00000000",
-- lw $R3,0($R0)
8 => "10001100",
9 => "00000011",
10 => "00000000",
11 => "00000000",
This project is licensed under the MIT License - see the LICENSE file for details.