ankushbhardwxj / pyarm-assembler

Assembler for ARM7 written in Python

PyARM-Assembler

Assembler for ARM assembly language.

An assembler is just a simple program that is supposed to convert assembly code to machine code(binary).
A linker may be further implemented for execution. Given an ARM7 assembly code to our assembler, we want it to spit binary.
eg:

MOV R3, R9   # assembly
1110 0001 1010 0000 0011 0000 0000 1001  # binary

An assembler has two passes, coz it skips certain lines in first pass.
Read input line, parse the opcode, check for operands, addressing modes etc,
get all 8 bits and write them to a object text file.
This assembler, however, is an one pass assembler.

How to run ?

python assembler.py -f fileName.s 

For debugging, set the debug variable in source equal to 1.

Some material :

• ARM Assembly: ARM assembly doc.
• Assembler Steps
• see page 32
• Working
• A C based assembly parser
• Standard Assembly book
• ARM7 Instruction Set
• A good resource

Future Work

• Make a 8051 version of this, preferably using Chapel Language.

pyarm-assembler's Issues

Add condition feature

TODO: Currently default bits for condition is 0000, we should parse condition in a given line and use its specific binary bits in our binary string.

Complete remaining instructions

MOV, Shift and other complex instructions haven't been completed yet because complex assembly programs were not yet tested. Implement each of them from documentation.