PDS-style source editor
A source editor aimed specifically at 6502 assembly, with the sort of keyboard-driven workflow old PDS users would expect.
IN DEVELOPMENT
RETRO PROJECT / PDS6502.COM
PDS 6502.
In a browser.
This is a retro-computing project to build a web-based PDS6502 assembler/compiler environment for the Commodore 64. The idea is simple: edit 6502 source in the browser, assemble it, inspect what came out and run it on a C64.
READY.
38911 BASIC BYTES FREE
38911 BASIC BYTES FREE
$0801
LOAD ADDRESS
LOAD ADDRESS
THE TARGET MACHINE / 1982
6502 ASSEMBLY◆PDS HERITAGE◆C64 DEVELOPMENT◆BROWSER TOOLCHAIN◆6502 ASSEMBLY◆PDS HERITAGE◆C64 DEVELOPMENT◆BROWSER TOOLCHAIN
01
THE PROJECT
What this site
is about.
PDS was a professional cross-development system. You wrote and assembled the code on the host machine, then sent it to the target and debugged it there. For 6502 work that meant fast edit / assemble / test cycles without having to develop entirely on the 8-bit machine.
PDS6502.com is an attempt to recreate that sort of workflow in a browser for the C64. It is not intended to hide the hardware. Addresses, bytes, symbols, load locations and the generated machine code should all remain visible.
PDS HERITAGE
PC host.
C64 target.
The original idea was straightforward: use a more capable machine for editing, assembling and debugging, while the 6502 machine remained the target. Here, the browser takes the place of the host side and the Commodore 64 remains the machine we are interested in.
+ Edit. Assemble. Load. Run. Debug.
; PDS6502.COM — WEB CROSS DEVELOPMENT
ORG $0801
START SEI
LDA #$00
STA $D020
STA $D021
CLI
LOOP INC $D020
JMP LOOP
BUILD $0801 - $0811 17 BYTES
OK 0 ERRORS / 0 WARNINGS
█
02
CURRENT JOB LIST
Things that need
to work.
6502 assembler core
6502 opcodes, labels, symbols, expressions, PDS-compatible directives where practical, and predictable machine-code output.
PLANNED
PRG output
Produce C64 PRG files with the correct load address so a build can be dropped straight into an emulator or transferred to real hardware.
PLANNED
Symbols & diagnostics
Listings, symbol tables and errors that show exactly where the assembler got upset and what bytes were generated.
PLANNED
Memory & monitor tools
Inspect memory, addresses, registers, assembled output and symbols without turning it into a modern IDE debugger.
PLANNED
C64 integration
Assemble, load and run on an embedded C64 emulator first, with real-machine transfer options considered later.
PLANNED
6502
There are only
so many opcodes.
The useful part of 6502 programming is that very little is hidden. A, X and Y are right there. Zero page matters. Page crossings matter. The stack is tiny. PDS6502 will keep those details in view instead of pretending the target is something it is not.
AXYSPPCP
PDS / 6502
PDS
6502
Assembler
& Monitor
manual
A9 00 8D 20 D0
4C 06 08
4C 06 08
THE ORIGINAL MANUAL
The original
manual.
A scan of the PDS 6502 Assembler & Monitor manual survives online. It is useful reference material for the assembler syntax, expressions, directives and monitor commands, and it will help guide compatibility work on this project.
Open the surviving manual ↗ Cover shown here is a visual recreation, not a scan of the original manual.
CURRENT TARGET
C64
CPU 6510 / 6502 code
LOAD $0801 and wherever you tell it
OUTPUT PRG + symbols + listing
HOST your browser
No cloud build farm. No framework. Just source in, bytes out.
PDS6502.COM
Work in progress.
There is nothing to download yet. The assembler, editor and C64 workflow are being built now. This page will turn into the actual tool as the useful parts come online.
↑