/islyd-asm

Simple assembler for the VHDL processor described in https://catedra.ing.unlp.edu.ar/electrotecnia/islyd/seminario_micro.html

Primary LanguagePythonOtherNOASSERTION

islyd-asm

Simple assembler for the VHDL processor described in https://catedra.ing.unlp.edu.ar/electrotecnia/islyd/seminario_micro.html

Installation

On most cases running

$ pip install --user .

from the top level source directory should do.

Usage

$ islyd-asm --help
usage: islyd-asm [-h] [-o OUTPUT] asmfile

positional arguments:
  asmfile               Assembler source file

optional arguments:
  -h, --help            show this help message and exit
  -o OUTPUT, --output OUTPUT
                        Compiled IHEX file name (defaults to asmfile with hex suffix if not provided)

Syntax

  • Labels and definitions are case sensitive

  • Instructions are case insensitive

  • Comments start with a semicolon, can be either alone or after a label/definition/instruction

  • Numeric literals and addresses are all in hexadecimal and prefixed with a dollar sign, like:

    $abcd

  • Labels are just a string of word characters (whatever \w matches in a regular expression) that ends in a colon.

    There should be no space between the label and the terminating colon. It is not necessary to define a label on the first column only but it improves readability

    some_label:     ; Good
some_label :    ; Not good.

  • Definitions take the form of:

    identifier EQU value

    All the occurences of identifier are replaced by the literal value. No further expansion is performed.

Instruction set

  • CLR RX Clears register RX
  • INC RX Increments contents of register RX by 1
  • DEC RX Decrements contents of register RX by 1
  • DEC RX IF NOT ZERO
  • STR RX, address, label or definition
  • LDD RX, address, label or definition
  • LDI RX, address, label or definition
  • LDI IX, address, label or definition
  • LDI RXH PORTB
  • INC IX
  • LDD RX, IX
  • STR RX, IX

Flow control

  • NOP no-op
  • RST Resets processor
  • JMP PC, address, label or definition
  • JMP PC IF Z, address, label or definition
  • JMP PC IF C, address, label or definition
  • BTJC bit number or definition , address, label or definition , PORTB
  • BTJS bit number or definition , address, label or definition , PORTB

Arithmetic

  • NOT
  • SWAP RX
  • SLA RX
  • SRA RX
  • SLL RX
  • SRL RX
  • AND address, label or definition
  • OR address, label or definition
  • XOR address, label or definition
  • NAND address, label or definition
  • NOR address, label or definition
  • XNOR address, label or definition
  • ADD address, label or definition
  • SUB address, label or definition
  • ADDC address, label or definition
  • SUBC address, label or definition

Port manipulation

  • INC PORTA
  • DEC PORTA
  • STR RXL PORTA
  • BIT SET bit number or definition , PORTA
  • BIT CLR bit number or definition , PORTA