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A comment on The DooM-chip: no CPU, no opcodes, no instruction counter. Parent comment

Re:The DooM-chip: no CPU, no opcodes, no instruction counter by sylefeb on Saturday May 09, 2020 @11:36AM (#23125579)
Author here - Thanks! You are absolutely correct there are several state machines (vga, sdram controler, framebuffer, texturing, divider, renderer, etc) and each with an active state index. The renderer is the biggest one with 69 states.

I agree the state index can be seen as an instruction counter, albeit into very specialized instructions: there are no two same instructions in a given module, each is uniquely implementing a precise subpart of the algorithm. Also the states decide the flow and select the next state, there is no list of instructions you could program or re-arrange. So I wanted to capture this idea that the algorithm is completely embedded into the circuit itself, which is not capable of doing anything else.

There is definitely a very interesting trade-off between a general instruction set and an extremely specialized state machine like here - combining both seems promising?

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Re:The DooM-chip: no CPU, no opcodes, no instruction counter by floppy123 on Sunday May 10, 2020 @12:35PM (#23133925)
Question is: How far will you go, fully playable level?
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Re:The DooM-chip: no CPU, no opcodes, no instruction counter by sylefeb on Monday May 11, 2020 @02:48PM (#23145554)
Unsure, I definitely would like to have fully working environments that can be explored interactively (with proper BSP collisions, doors/lifts, blinking lights etc). Everything is stored in BRAM, unsure the sprites would fit (maybe a few, or at lower res, but I did not look into that yet). When this gets released I hope this will also be reused/expanded.

My initial objective was more about creating some non-trivial hardware using the language I am working on, as well as learning how to implement and optimize algorithms in the context of FPGA. Due to my background in graphics / game programming, revisiting the Doom renderer was a perfect test case! Now that I have this first prototype I want to optimize and fine tune it some more, before adding too many features -- especially as this is meant to serve as a tutorial/example for the language.

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