/assembler

a utility to create binary from asm.

Primary LanguagePythonMIT LicenseMIT

assembler

a utility to create binary from asm.

  • One instruction or label per line.
  • Blank lines are ignored.
  • Case insensitive
  • Comments start with a '*' as the first character and all subsequent characters on the line are ignored.
  • Spaces and commas delimit instruction elements.
  • All immediate values are to be specified using '#' character, optionally format can also be specified. Valid formats are binary(b), hex(h), decimal(d). By default decimal is assumed.
    python3 asm.py -h

gives:

usage: assembler [-h] [-o O] inputfile

create binary from asm

positional arguments:
  inputfile   input file path

optional arguments:
  -h, --help  show this help message and exit
  -o O        output file name,defaults to a.txt

primarily made to be used for vhdl projects

an example,

python3 asm.py sample.txt -o out.txt

creates out.txt in the same directory.

Language definition:

ADD RC RA RB  - execute RC <= RA + RB
ADC RC RA RB  - execute RC <= RA + RB if carry
ADZ RC RA RB  - execute RC <= RA + RB if Zero
ADL RC RA RB  - execute RC <= RA + RB(shift left by 1) 

ADI RC RA I6  - execute RC <= RA + I6(sign extended)

NDU RC RA RB  - execute RC <= RA nand RB bitwise
NDC RC RA RB  - execute RC <= RA nand RB bitwise if carry
NDZ RC RA RB  - execute RC <= RA nand RB bitwise if Zero

LHI RA I9     - execute RA <= I9(shift left by 7)

LW  RA RB I6  - execute RA <= M[RB+I6]
SW  RA RB I6  - execute M[RB+I6] <= RA
LM  RA I9     - see below
SM  RA I9     - see below

BEQ RA RB I6  - branch to PC+I6 if RA == RB
JAL RA I9     - RA <= PC+1, branch to PC+I9
JLR RA RB     - RA <= PC+1,branch to addr in RB
JRI RA I9     - branch to RA+I6

LM/SM: Load(Store) multiple registers whose address is given in the immediate field (one bit per register, R0 to R7) in order from right to left, i.e, registers from R0 to R7 if corresponding bit is set. Memory address is given in reg A. Registers are loaded from (are stored to) consecutive addresses.

Note assember can detect quite a few syntax errors but they aren't guaranteed to be exhaustive.

Potential Upgrades:

  • Right now it's a very messy code. We want to clean it up and remove redundancies
  • support for labels
  • include a command line flag to get various output formats