Lies, Damned Lies and Benchmarks.

Using, learning, programming and modding the Gigatron and anything related.
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bmwtcu
Posts: 111
Joined: 01 Nov 2018, 12:02

Re: Lies, Damned Lies and Benchmarks.

Post by bmwtcu »

Nice! Where do I read about Mode 1975?
at67
Posts: 479
Joined: 14 May 2018, 08:29

Re: Lies, Damned Lies and Benchmarks.

Post by at67 »

bmwtcu wrote: 04 May 2022, 02:45 Nice! Where do I read about Mode 1975?
Search for 1975 in https://github.com/kervinck/gigatron-ro ... ctions.txt

And:

Line 3149: https://github.com/kervinck/gigatron-ro ... dev.asm.py

Code: Select all

xora((1975>>8)^(1975&255))      #26 Poor man\'s 1975 detection
bne(pc()+3)                     #27
bra(pc()+3)                     #28
assert videoZ == 0x0100
st([vReturn])                   #29 DISABLE video/audio/serial/etc
The code detects 1975 as the parameter to sys_SetMode and sets [vReturn] to 0; this effectively switches the bit-banger to no video, no audio, no input, etc: which allows for 521 scanlines x 200 cycles worth of uninterrupted vCPU interpretation per video frame. (which is about double the number of available vCPU cycles compared to mode3, the single scanline mode).

P.S. There are no sync signals in this mode, so your monitor loses sync until you pass -1 back to sys_SetMode.
veekoo
Posts: 78
Joined: 07 Jun 2021, 07:07

Re: Lies, Damned Lies and Benchmarks.

Post by veekoo »

Like in the OpenGL programming. You first calculate graphics in a frame and only after that you draw the frame.
veekoo
Posts: 78
Joined: 07 Jun 2021, 07:07

Re: Lies, Damned Lies and Benchmarks.

Post by veekoo »

This 1975 mode could make Mandelbrot faster. New Mandelbrot draws in 1min 17sek in fast screen mode.
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