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)”
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 …
Try out the completed N-Queens project discussed in this post You may have noticed from my last few posts that I’ve been adding support for the C programming language to my db65xx debugging extension for VS Code. When I first started with cc65, the added complexities needed to program in C kept me firmly in …
Continue reading “C Coding: Tripped Up by a Carraige Return”
I’ve added the capability to view local variables in C functions to the db65xx VS Code extension. I plan to write a bit more about this, but for now, here are a few screenshots. You can try it out with my Sieve of Eratosthenes project.
12/17/2022 Update: db65xx now handles normal debug stepping within C files. I successfully ran my C-based Hello World example project in my VS Code db65xx Debugging Extension but needed a more rigorous test of C-based debugging. I often go to Rosetta Code to look for code samples to test on my various builds and find …
I’ve added some support for C-based debugging in the VS Code db65xx Debugging Extension. Try it and other example projects out in my db65xx projects repository.
I like trying out new programs on things I build and doing so on my VS Code db65xx debugging extension is no exception. I found a fun little chess program by Oscar Toledo that was easy to port to cc65 and needed only a few I/O modifications to get running on db65xx. It doesn’t play …
Continue reading “6502: Playing Chess on the VS Code db65xx Debugging Extension”
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 added support for the 6502 and 65C02 microprocessors to my db65xx VS Code debugging extension. Here is an image of me debugging my 65C02-based Forth operating system.
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, …
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 …
Build 4 – Current Specification As of 7/15/2022, Build 4 has tested successfully with: Both 65C02 and 65C816 up to 10 MHz where I started to get display glitches 524k memory. Current configuration: ~457k RAM ($0000-$F7FF, $20000-$7FFFF), 55 ns ~67k ROM ($F800-$1FEFF), 70 ns 256 bytes I/O ($1FF00-$1FFFF) 65C22 VIA ($1FF10, shift register dedicated to …
Continue reading “65816: Build 4 – Current Status – 7/15/2022”
Off and on throughout my Build 4 troubleshooting journey I kept wondering if the PLD was the underlying issue. While a PLD is handy for making after the fact changes to your build’s memory map, it also has a handy feature I hadn’t thought of before. Since the PLD brings control input and output signals …
Continue reading “65816: Build 4 – Troubleshooting 4 – Testing a Different Address Decoder”
I left Build 4 successfully running with the 65816 and 55 ns RAM. But it failed with memory corruption when I used 12 ns RAM. The problem was that occasionally during RAM writes, some address signals would change about 2 ns before the write enable signal would rise. This would result in a write to …
Continue reading “65816: Troubleshooting 3 – Revisiting the Build 4 Layout”