Assemblitor

Assemblitor is a light-weight editor for a simple dialect of Assembly.

Easily write, edit and execute your code in a visual user interface that comes with some quick tools to help you develop.

Requirements

• Python 3.10+
• Pillow 10.0.0+

Getting Started

Open "Assemblitor/Assemblitor.pyw" to start the program.

The Language

This Assembly dialect is a low-level column-oriented programming language that is close to machine code. It is case-insensitive.

The language consists of a sequence of memory cells (MCs) that can store values or commands. Each MC starts with its address and ends with a line break. The MCs have to be in increasing order but empty ones don't have to be displayed. A value has to be stored after the address as an integer. An empty MC will be interpreted as having a value of 0. A command is also stored after the address, with most of them requiring operands to work. Comments can be made with a semicolon. All text between the semicolon and the next line break will be ignored by the computer.

The program orients itself to the architecture of a von Neumann processor. This means it takes usage of the program counter (PC), the accumulator (ACC) and the instruction register (IR). The PC is set to 0 by default. If the program is executed, the command at the address stored in the PC will be loaded into the IR. There the command can be executed. After its execution the PC gets increased by one (excluding jumps and stops) and the next command can be loaded into the IR.

A simple program may look like this:

00 LDA #4 ; load the value 4 into the ACC
01 STA 04 ; store the value of the ACC into the 4th MC
02 STP    ; stop the program

This would be the result after executing the program:

00 LDA #4
01 STA 04
02 STP
04 4      ; a stored value

All accepted commands:

Command	Description
STP	Stops the program
LDA n	Loads the value at MC n into the ACC
LDA #n	Loads the value n into the ACC
LDA (n)	Loads the value of the MC that has the address that is stored in MC n into the ACC
STA n	Stores the value of the ACC into MC n
ADD n	Adds the value at MC n to the value of the ACC and stores the result into the ACC
ADD #n	Adds the value n to the value of the ACC and stores the result into the ACC
ADD (n)	Adds the value of the MC that has the address that is stored in MC n to the value of the ACC and stores the result into the ACC
SUB n	Subtracts the value at MC n from the value of the ACC and stores the result into the ACC
SUB #n	Subtracts the value n from the value of the ACC and stores the result into the ACC
SUB (n)	Subtracts the value of the MC that has the address that is stored in MC n from the value of the ACC and stores the result into the ACC
MUL n	Multiplies the value at MC n by the value of the ACC and stores the result into the ACC
MUL #n	Multiplies the value n by the value of the ACC and stores the result into the ACC
MUL (n)	Multiplies the value of the MC that has the address that is stored in MC n by the value of the ACC and stores the result into the ACC
JMP n	Jumps to MC n by setting the PC to n
JZE n	Jumps to MC n by setting the PC to n if the value of the ACC is equal to zero
JLE n	Jumps to MC n by setting the PC to n if the value of the ACC is less than or equal to zero

The Editor

The editor consists of a menubar, a toolbar and the two code blocks. Write your Assembly program in the left code block and execute it by clicking the green button on the left of the toolbar. You will find your executed code in the right code block. Use the orange button to execute one step at a time. If you want to adjust addresses or operands, you can use the de-/increment tool found right to the execution buttons on the toolbar. Simply select the code you want to change and click the blue buttons. You can adjust the step size through the spinbox and which numbers it should affect with the option menu.

Shortcuts

Shortcut	Description
F5	Run program
Shift + F5	Run single step
Ctrl + Z	Undo change
Ctrl + Shift + Z	Redo change
Ctrl + Y	Redo change
Ctrl + Backspace	Delete whole word
Shift + Enter	Line break without address
Shift + Tab	Switch affected numbers
Shift + Scroll up	Increment affected numbers
Shift + Scroll down	Decrement affected numbers
Ctrl + N	New file
Ctrl + O	Open file
Ctrl + R	Reload file
Ctrl + S	Save file
Ctrl + Shift + S	Save file as

Known Bugs

See "todo.md"

Acknowledgments

The whole project is rooted in and inspired by an old Delphi emulator used by my school at that time. In fact, the Assembly dialect is almost exactly the same, with a few added conveniences and a more open spacing/commenting syntax.

Contributing

Found a bug? Tell me on GitHub. You can also contribute by suggesting features or translating Assemblitor to another language.