It was recently brought to my attention that Darren Atkinson has a really good summary of the invalid register exchange and transfer opcodes in the 6809. So good, that I should use the information to make MAME’s 6809 better match … Continue reading
Here is the latest release of GCC6809-CoCo. This is the GNU C compiler targeted for the Color Computer. I have based this work on Brian Dominy’s GCC6809.Current releases:Mac OS X package 20071007CYGWIN/Windows package 20071007Source package 20071007Please report any bugs and … Continue reading
I maintain a little diff patch for MAME and MESS that I call emubrk. This is an opcode that will cause the debugger to pop up when it is encountered in the instruction stream. Attached you’ll find the patches for … Continue reading
What is this? In the first three months of 1979 BYTE magazine published a series of articles describing the brand new microprocessor: the 6809. Written by the co-designers of the 6809, these articles are a fascinating trip down memory lane. … Continue reading
GIME Hardware Cursor Extension Proposal Overview The GIME video system can provide a hardware mouse cursor by adding a small independent cursor overlay. The cursor is not stored in normal CoCo memory and does not require software to modify the … Continue reading
Color Computer Emulator Disk Image Tools RBF-Studio RBF-Studio Website: https://gitlab.com/i440bx/rbf-studio CoCo File Image Utility FIU Project: ? Formats: ? GUI: ? Website: https://drive.google.com/drive/folders/1jBCOk4TgNj5XINNRegEWGye03VK_T4QT Toolshed decb Project: Toolshed Formats: Headerless Disk Sector Dumps GUI: No Website: https://github.com/nitros9project/toolshed cecb Project: Toolshed Formats: … Continue reading
Reverse Engineering the CoCo Speech/Sound Cartridge Sound Activity Circuit The Color Computer Speech/Sound Cartridge (S/SC) was one of the more ambitious peripherals Tandy produced for the CoCo line. It packed a TMS-7040 microcontroller, an SPO256-AL2 speech synthesizer, an AY-3-8913 programmable … Continue reading
I wrote a newish 6809 and 6309 disassembler. https://www.macmess.org/follow9.html. Its just two files, an HTML and JavaScript file. Copy them locally, host them on another site, what ever. There is also a git hub so you can do a pull … Continue reading
An interesting bug appeared on MAME Testers recently. The bug linked here is really simple. OS-9 wont boot on a copy protected disk image. The solution also was simple: properly emulate the delay between issuing a write command, and the … Continue reading
Welcome to Salient Assembly. The show where we deep dive into a very specific 6809 assembly language topic. Today we’re talking about calling subroutines. Subroutines are a very important aspect to programming. When ever you find yourself needing to do … Continue reading