Beeb VSC
A Visual Studio Code Extension to support code development for the Acorn BBC Micro/Master range of 6502 based micro computers from the 1980's.
Visual Studio Code is free and really good for general retro/6502 development, so this extension was created to enhance the experience by providing syntax colouring for 6502 opcodes, labels, and BBC BASIC commands & functions supported by BeebAsm as well as various types of VS Code functionality.
See the CHANGELOG for full release history.
Features
Syntax Highlighting:
- All 6502 op-codes (no 65C02 op codes yet)
- .label style labels
- $ or & style hex constants
- All BBC BASIC style keywords (such as
TAN, RND, MOD, DIV etc.)
- All BeebAsm directives (such as
ORG, GUARD, SKIP etc.)
- BeebAsm functions (
RND, CHR$, LO etc.)
- BeebAsm directives (
SAVE, EQUB, ORG etc.)
- Op-code information (description, bytecode, cycles etc.)
- Symbols and labels show the line of code where they are declared
- Can also show cycle count as inlay hints
References:
The various types of reference navigation options available within VS Code via the context menu (right-click on a symbol or label).
- Go to definition
- Find all references
- Peek definition/references
- Links added to files referenced via
INCLUDE, PUTBASIC or PUTTEXT
- The rename refactoring functionality is also included
Diagnostics:
The extension parses your code to try and identify the errors that would be reported by BeebAsm when compiling your code. Lines with issues will be underlined and reported in the Problems tab of VS Code. Dozens of issues are detected including:
- BeebAsm function and directive syntax errors
- Assembly errors (e.g. branch out of bounds, invalid addressing modes)
Completions:
Provides a list of potential matches as you start to type.
- BeebAsm functions
- BeebAsm directives
- Symbols and labels
Supported Filetypes:
- Assemble & test 6502 projects all within Visual Studio Code
- Assembly errors are parsed and sent to VSC's built-in error navigation view
- Uses Visual Studio Code tasks for building & testing
- Easily create new build targets (supports multiple targets within a project folder)
- Easily select 'default' build targets
- Run build targets in the emulator of your choice
Integrated BBC Micro Emulator
- Preview your projects directly within VSCode using an integrated JSBeeb emulator
- Even debug your projects by setting breakpoints in your code, steping through and monitoring how values change (using named symbols and labels).
Quick Setup
1. Install the extension
Press CTRL+Shift+X in VS Code, search for 'beeb vsc' or 'beebasm', click install.
2. Install Assembler and Emulator
By default, BeebVSC configures BeebAsm.exe as the default assembler, and BeebEm.exe as the default emulator, and assumes that these executables are can be located on the system path. If not, simply add paths to them in your global Windows environment variables.
3. Load your project
Open your project folder in VSC. Syntax colouring will automatically activate when .6502, .asm, or .s files are opened in the editor.
4. Create a new build target
Press F10 and the extension will provide a drop down list of compatible source files it has found in the current workspace.
Select the one that you wish to assemble with BeebAsm, and a new build target will be created in your workspace.
A tasks.json file will be created in a .vscode folder in your workspace containing the required tasks to build or run your targets. A settings.json file will also be created in the same location and is used for identifying the target source file(s) so we can parse the files in a suitable order even when viewing a different source file.
5. Build the target
Press F7 or Ctrl+Shift+B and Visual Studio Code will build(assemble) the source file you selected and output a disk image <sourcefile>.ssd.
Any errors output by the assembler will be captured in Visual Studio Code's Problems view.
6. Run the target
Press F9 or Ctrl+Shift+T and Visual Studio Code will run your disk image with the currently configured emulator (BeebEm by default).
Alternatively, right-click on your disk image and select BeebVSC: Open Emulator to open with the built-in copy of JSBeeb.
7. Debug (experimental)
Step 1 - Create source map
With your assembly file in focus, open the command palette and select BeebVSC: Create source map. If your file is called build.asm, it will create build.asm.map with information about labels, symbols, and the addresses at which instructions are run.
Step 2 - Run debugger
Right-click your disk image and select BeebVSC: Debug to open the JSBeeb emulator in debug mode. You can now set breakpoints in your code, add watch points and step through the code. See below debugging section for more details.
That's it! Have fun!
Advanced Usage
Changing Assembler and/or Emulator configuration
If you wish to change your Assembler or Emulator configuration, go to File->Preferences->User Settings in Visual Studio Code, the editor will present current user preferences. Scroll to the bottom of the configuration until you see the BeebVSC settings. Copy the settings "beebvsc.assembler" and "beebvsc.emulator" across to your user settings and modify accordingly. Note that although full paths to executables can be included here, we do not recommend this since they are not portable if your project source is shared.
Managing multiple build targets
You can run the add build target command multiple times to add additional source files to the list of build targets in the tasks.json file.
Switching between build targets
It is possible to switch between build targets as follows:
Press F6 and the extension will provide a drop down list of build targets currently in the tasks.json file.
The selection you make will become the new default 'build' and 'test' target, which can then be built as normal by pressing F7 or Ctrl+Shift+B, or similarly, pressing F9 or Ctrl+Shift+T to run in the emulator.
NOTE: It is not possible to add duplicate targets, also note that only one target can be built at once.
Listing commands
Press Ctrl+Shift+P to open the command palette. In here you will see the BeebVSC commands listed for reference/convenience.
Running specific tasks
BeebVSC takes advantage of standard Visual Studio Code 'tasks', which are just a list of named shell commands stored in the .vscode/tasks.json file. Each task is 'runnable' in its own right, so another useful shortcut is Ctrl+Shift+R to list all of the current tasks, which you can then manually select.
Adding custom tasks
The BeebVSC extension is careful to preserve the contents of the tasks.json file. Therefore once targets(tasks) have been added, is very easy to manually configure or override them by simply making modifications to the tasks.json file directly:
- You can rename targets if you wish, there is no logic dependent on this
- You can modify commandline arguments if you wish
- You can your own additional commandline tasks if you like (eg. for compiling other data etc.)
- You can manually remove tasks if you wish
The only property that is managed by the extension is Group -> Kind, so this is subject to modification.
Note also that the commandline argument for the test task is managed by the extension, and updates whenever a new build target is selected.
Directly managing target source files
If you don't want to use BeebVSC's functionality to add build targets, some functionality will be limited because the extension will not know what order INCLUDE files are processed. In this case, it is necessary to add the target file(s) to the settings.json file. For example, if the targets build.asm and loader.asm are run through BeebAsm then the settings file would look like:
{
"beebvsc": {
"sourceFile": [
"/Users/Games/Test/build.asm",
"/Users/Games/Test/loader.asm"
],
"targetName": "main.ssd"
}
}
The easiest way to set this up is adding the build targets in a normal way and they removing the tasks.json entries if those are not wanted.
Debugging
Debugging is enabled through a two-stage process. Whenever the code is changed, a new source map must be generated through the BeebVSC: Create source map command. This uses the built-in logic from BeebAsm to create a map from each opcode in your code to the address at which it will be run. Eventually it would be better to have this file generated by BeebAsm itself but while the feature is experimental, this gives us more control.
Then the built-in copy of JSBeeb needs to be launched in debug mode. This can be done in two ways.
- Just right-click on the disk image and select
BeebVSC: Debug
- Set up a
launch.json file so that you can just press F5 to start debugging with a specific disk image and named source map file(s). A template for this is included, so you can go to the Run and Debug panel in VS Code and click create a launch.json file to get an initial template, then update the diskImage and sourceMapFiles fields.
Example launch.json
{
"version": "0.2.0",
"configurations": [
{
"type": "jsbeebdebugger",
"request": "launch",
"name": "Debug in built-in jsbeeb emulator",
"diskImage": "${workspaceFolder}/mygame.ssd",
"sourceMapFiles": [
"build.asm.map"
]
}
]
}
Watches can be set for symbols and labels from your code (assuming they relate to 16 bit addresses).
- Add prefix of
$ or & for hex display, % for binary display, leave blank for decimal
- add suffix of
.w for 16 bit (little endian) reference or .d for 32 bit. Defaults to 8 bit value
Examples:
Inlay hints for cycle count
The cycle count for each assembly instruction can be shown inline by enabling the setting "beebvsc.enableInlayHints". The precise behaviour is controlled from the standard VS Code setting "editor.inlayHints.enabled".
Linux/Mac support
The installation is for Windows by default, but its quite feasible to get it working for Linux and MacOS. Primarily this is done by changing the settings for "beebvsc.assembler" and "beebvsc.emulator".
Possible further features to add
- Support for BBC BASIC text files (can be compiled to SSD via BeebAsm) and full syntax colouring
- Support 'remove target' feature
- Support different 6502 assemblers
- Support more debug targets e.g. B2
Contributors & Kudos
Many thanks to the following people who have contributed directly & indirectly to this project:
More information here about developing the extension.
Emulators
BBC Micro/6502 Resources:
