An instruction-level assembler/simulator for the LC-3b ISA.
The LC-3b is a toy instruction set architecture developed by Yale Patt and Sanjay Patel for their book, "Introduction to Computing Systems: From Bits and Gates to C and Beyond" (McGraw-Hill, 2003). The book actually uses a version of the ISA called LC-3, which is word-addressable. The LC-3b is the byte-addressable variant.
LC-3b is a 16-bit architecture; all the registers are 2 bytes wide. The full specification lives here.
This project consists of a simple assembler and simulator for the LC-3b written in Haskell. I did it just for the sake of doing it, but hopefully it's useful to somebody.
This is a Haskell project with a few dependencies, all of which are on hackage. I use stack to build it. If you have stack installed, you should be able to run
stack build
Alternatively, you can run
cabal build
I also recommend running
stack test
which assembles and simulates all the test programs, and checks the final register state to make sure the thing ran correctly. You can actually write your own tests and insert them into the tests/ directory in the same format as the other tests that are already in there.
This project compiles two executables, lc3b-asm and lc3b-sim. lc3b-asm takes a single assembly file as a command line argument, assembles it, and outputs a file with a .out extension right next to the input file. There are no command line switches or anything. Same goes for lc3b-sim -- essentially, you feed that program the assembled .out file, and it will simulate it, outputting the final state of the PC and register file upon completion. If you want to see the state of the memory, you are out of luck unless you are willing to hack on the sim/Main.hs code yourself. You can also give lc3b-sim multiple input files; it is assumed the first one is the program and the other ones are just data.
Might be fun to write a C compiler that targets LC-3b assembly.
- TODO: Improve test suite; add more complex tests that require several object files.
- TODO: Make a disassembler tool