Category Archives: Uncategorized

Optimizing 6809 Assembly Code: Part 3 – Stack Blasting and Self Modifying Code

Table of Contents (click on a link to jump to that web page) Part 1 – Quick and Easy Changes to Speedup Your Code Part 2 – Speedup Storing Data – Unrolling Loops Part 3 – Stack Blasting and Self Modifying Code … Continue reading

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Sprite Compiler for the TRS-80 Color Computer 3

What are sprites anyways? Sprites are little blocks of data that you move around the computer screen.  Usually used to move the characters around the screen in games such as Mario or the barrels moving around in Donkey Kong, they … Continue reading

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How to make PMODE 4 CSM video files for the CoCo (TRS-80 Color Computer)

Hi All, Using some awesome free tools a bash script and a little C program I wrote it’s possible to make PMODE 4 colour videos that playback at 23.3 fps with sound and have four colours – black, white,  and … Continue reading

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Zilog z80 to Motorola 6809 Transcode – Part 025 – My z80 to 6809 program

To end this series on transcoding the z80 code to the 6809 I thought I should include my c program called z80_to_6809_15_Pacman.c it is what I used to help with the transcode.  It takes a z80 disassembly as input and … Continue reading

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Zilog z80 to Motorola 6809 Transcode – Part 024 – PAC MAN is finally complete, if you have a CoCo 3 with 512k give it a try…

Hello, well I’ve finally completed my translation from the z80 arcade version of PAC MAN to the 6809 for the CoCo 3.  If you want to play it download version 1.01 here (Update – this version no longer includes any executable … Continue reading

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Zilog z80 to Motorola 6809 Transcode – Part 023 – Optimized sprite rendering, combining Compiled sprites with Stack Blasting

Talking with other CoCo users about optimizing the sprite rendering on the CoCo I’ve figured out the best way to render the sprites for Pac Man on the CoCo3.  This article will summarize what I’ve learned and then explain what … Continue reading

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Zilog z80 to Motorola 6809 Transcode – Part 019 – You can try it, if you want…

Hello, First things first, just so I don’t get anyone telling me.  At this point Pac Man is slow about 1/3rd the speed of the original arcade machine.  The cutscenes need to be fixed and there is no sound…  Other … Continue reading

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