Solving differential equations on a 6502 with Woz's floating point code
1–10 of 14 posts
Re: Solving differential equations on a 6502 with Woz's floating point code
#2Very interesting ... thanks for pointing to py65 as well
Re: Solving differential equations on a 6502 with Woz's floating point code
#3Awesome. I love projects like this.
Re: Solving differential equations on a 6502 with Woz's floating point code
#4Not the floating point, but saw his code for other parts of the 6502 Apple products, he really was a genius. The code is both very clever AND quite understandable.
My understanding is his circuit design was similar. One thing, use a part of the circuit for two different things at different points of the clock cycles, so parts count was reduced.
Re: Solving differential equations on a 6502 with Woz's floating point code
#5I find it funny that people enjoy the nostalgia of things like 6502... I loved my Atari 800XL, but wistfully dreamed that computers might one day be able to handle 320x240 with 256 colours.... boy... that would be good! Meanwhile I was hand assembling 6502 into data sections in basic so I could try and draw a circle... who knew drawing circles was so ridculously difficult and slow?
Having said that, I do like this stuff in hindsight :)
Re: Solving differential equations on a 6502 with Woz's floating point code
#6I find it funny that people enjoy the nostalgia of things like 6502... I loved my Atari 800XL, but wistfully dreamed that computers might one day be able to handle 320x240 with 256 colours.... boy... that would be good! Meanwhile I was hand assembling 6502 into data sections in basic so I could try and draw a circle... who knew drawing circles was so ridculously difficult and slow? Having said that, I do like this st…
Were you using a CORDIC algorithm? Bit shifts and adds, no multiplies required.
Re: Solving differential equations on a 6502 with Woz's floating point code
#7I find it funny that people enjoy the nostalgia of things like 6502... I loved my Atari 800XL, but wistfully dreamed that computers might one day be able to handle 320x240 with 256 colours.... boy... that would be good! Meanwhile I was hand assembling 6502 into data sections in basic so I could try and draw a circle... who knew drawing circles was so ridculously difficult and slow? Having said that, I do like this st…
Were you using a CORDIC algorithm? Bit shifts and adds, no multiplies required.
no, I had hardcoded lookup tables. I was a teen with no real way to find out information about anything and just applied my high school math to the problem :)
Re: Solving differential equations on a 6502 with Woz's floating point code
#8Is that first-order approximation appropriate for iteratively solving the Diff EQ? Or does a higher order method such as Runge-Kutta have to be used? I notice the graphs don't align perfectly...
Re: Solving differential equations on a 6502 with Woz's floating point code
#9Not the floating point, but saw his code for other parts of the 6502 Apple products, he really was a genius. The code is both very clever AND quite understandable. My understanding is his circuit design was similar. One thing, use a part of the circuit for two different things at different points of the clock cycles, so parts count was reduced.
There's also "Sweet 16", Woz's "16-bit virtual machine" that's in the Apple ][ Integer basic ROMs. Another piece of pure genius code.
Re: Solving differential equations on a 6502 with Woz's floating point code
#10I find it funny that people enjoy the nostalgia of things like 6502... I loved my Atari 800XL, but wistfully dreamed that computers might one day be able to handle 320x240 with 256 colours.... boy... that would be good! Meanwhile I was hand assembling 6502 into data sections in basic so I could try and draw a circle... who knew drawing circles was so ridculously difficult and slow? Having said that, I do like this st…
Were you using a CORDIC algorithm? Bit shifts and adds, no multiplies required.
You don't need CORDIC to draw a circle. BTW, I implemented a CORDIC routine in 6502. It would really benefit from a barrel shifter which the 6502 does not have.
https://atariage.com/forums/blogs/entry/3385-atan2-in-6502/
In gist form https://gist.github.com/djmips/29a8fa9099bf92b31a7259da65915...