I’m using this post to gather some of the coding efficiencies I’ve found in moving to the 65816. Most of these relate to porting my 6502-based Forth operating system. I’ve documented many of these findings in my code and I figured it was better to have them here in one place rather than there buried …
Continue reading “65816: Coding Efficiencies (last update: 3/1/2023)”
I often use my blog as a reference of my previous work. Searching it today for VDA/VPA, I realized that I never wrote here about my findings regarding these 65816 pins. But I seem to recall having done so recently. Searching my social media more broadly I found that I had written a bit about …
In my last post I showed that you could run cc65 compiled C-based code on the 65816. The main limitation was that the C-based segments had to be located in Bank 0 (and of course that the standard C-library functions were running with 8-bit registers and none of the 65816 added instructions or address modes). …
Continue reading “65816: Running C-based Code Outside Bank 0 on the 65816”
I’ve been wondering for a while if I could run C-based code on the 65816 using the cc65 toolset. Browsing through the cc65 documentation and C libraries it’s pretty clear that the 65816 isn’t specifically supported. In fact, the C libraries are primarily targeted towards the 6502 with just modest support for the 65C02. The …
I’ve created a project to run Klaus Dormann’s functional tests in my VS Code db65xx debugging extension. Three test builds are available, one for the 6502, one for the 65C02 extended functions, and one testing the decimal mode. Here are some screenshots. Note that the 6502 and decimal mode tests can also be run on …
Continue reading “65C02: Running Functional Tests in the VS Code db65xx Debugging Extension”
I’ve created a GitHub repository with example projects for testing my VS Code db65xx debugging extension. If you already have cc65 installed, you can try out these examples with a few keystrokes. Here are a few screenshots: Basic terminal I/O Example of integrated terminal I/O. Prints “Hello world!” to the terminal and accepts keyboard input …
Continue reading “65816/65C02: Example Projects for VS Code db65xx Debugging Extension”
A reader recently asked me about some troubles he was having getting my 32-bit floating point package up and running. I thought it would be a great test for my new VS Code 65816 debugging extension. With just a few edits to the test program the reader was using, I was up and running in …
In my last post I discussed developing a debugging extension for VS Code for the 65816. It was pretty easy to get something up and going in a couple of days, but polishing it took a bit longer. It’s now available in the Visual Studio Marketplace and for modification at my GitHub, along with an …
Continue reading “65816: VS Code Debugging Extension Available”
I haven’t written much about debugging yet, but tools to help debug my code have been essential to my system development. I started out with the simple Ben Eater 6502 build where debugging consisted of repeating a cycle of write code, assemble and burn it to an EEPROM, and test the system for proper operation, …
As I was working on my 32-bit floating-point package (GitHub) I noticed some opportunities to optimize the code. For example, scale10, used while converting strings into floating-point values, uses the package’s 32-bit routines to multiply and divide by 10. For example, to scale up by 10 we load 10 to the floating-point stack and call …
I wrote in my previous post about testing my 32-bit floating-point package on a Mandelbrot plot. Paying forward Marco’s original 128-bit package contribution, I’ve made my 32-bit package available on my GitHub. It’s still a work in progress with limited functionality. But it’s still enough to handle Mandelbrot which was my original goal. Function Stack …
Continue reading “65816: 32-bit Floating-point Package Available”
I first got interested in the 65816 because of floating=point support. I had just finished porting Cosmic Conquest, an old text-based strategy game, to my 6502 system and was looking for other old games to port. I remembered an old text-based Star Trek game but on tracking it down discovered that it used floating point. …
Continue reading “65816: Floating Point – Finding a Balance Between Speed and Precision”
I haven’t talked much about my 65816 emulator but it’s been essential in porting my 6502 Forth over to my new 65816 build. The slowdown I mentioned in my post 6502: Coding – Just because it works doesn’t mean it’s correct though was becoming annoying. Starting up my Forth operating system in the emulator took …
Continue reading “65816 Emulator: Threading in Python Very Slow”
In a long postscript to 65816: Build 4 – Adding Expanded RAM I discussed some alternatives I tried to achieve the following memory map in my ATF22V10C PLD. There’s nothing magical about this memory map, it’s just something I wanted to try, for reasons I’ll discuss in a operating system post if I ever get …
I’ve mentioned previously having trouble getting WINCUPL to create the following memory map: I figured that since I was expanding ROM, I might as well give myself a full 32k of RAM. WINCUPL didn’t like that though, giving me an error that it didn’t have enough pterms for my ROM_CS pin. I took the easy …