riscv-disassembler

What is a disassembler?

A disassembler is a computer program that translates machine language into assembly language—the inverse operation to that of an assembler. Here are some sample RISC-V Instructions represented in assembly and machine language.

Assembly Language	Machine Language	Instruction Description
`lui a2, 44`	`00000000000000101100011000110111`	Loads the 20 upper-bits of 44 into register a2.
`blt a4, a5, 8`	`00000000111101110100010001100011`	Skips the next instruction if R[a4] < R[a5].
`addi sp, sp, -4`	`11111111110000010000000100010011`	Decrements the stack pointer by one word (4 bytes).
`sw s0, 0(sp)`	`00000000100000010010000000100011`	Stores the value at R[s0] into the stack.
`jalr x0, ra, 0`	`00000000000000001000000001100111`	Jumps to the address specified in R[ra].

Output

Run the executable on a file containing machine language to dissassemble and return all instructions in the input file as assembly language.

$ cat sample_input.txt
11111011011101111100111011100011
00000011001010110001100010100011
00000000000000101100011000110111
00000000000100000000000001110011
00000000000000000000000001110011
00000000111101110100010001100011
00000000000000001000000001100111
11111111110000010000000100010011
$ ./r5dis sample_input.txt
0:      blt a5, s7, -68
4:      sh s2, 49(s6)
8:      lui a2, 44
c:      ebreak 
10:     ecall 
14:     blt a4, a5, 8
18:     jalr x0, ra, 0
1c:     addi sp, sp, -4
20:     sw s0, 0(sp)

If run with no arguments, the executable will accept user input and return the disassembled instruction.

$ ./r5dis
Please enter a 32-bit binary string:
11111111111100101000010000010011
addi s0, t0, -1

Build Instructions

Just run make in order to build the executable!

$ make

orenazad/riscv-disassembler

riscv-disassembler

What is a disassembler?

Output

Build Instructions