ViTi95
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viti95.bsky.social
ViTi95
@viti95.bsky.social
Retro stuff and random things. FastDoom developer.
Reposted by ViTi95
Also, here's a glimpse at my rotoscoping process... #LUNARK #pixelart
December 1, 2025 at 5:16 PM
The MOVD (MMX register to general purpose register) instruction is really slow in the Cyrix FPU/MMX unit, which is why I think it's much slower than it should be.
December 3, 2025 at 1:22 PM
More tests! This one hurts: the IBM/Cyrix 6x86MX PR333 (tested at 225 MHz, 3.0×75):
- Cyrix 6x86 code path: 66.147 fps
- MMX code path: 46.160 fps (-30%)
Ouch.
December 2, 2025 at 10:47 PM
Another CPU that benefits from the MMX code: the Rise mP6. Running the exact same test:
- 486 code path: 37.432 fps
- MMX code path: 49.634 fps (+32.5%)
December 2, 2025 at 10:03 PM
Optimized it a bit further, and now we're at 57.120 fps (that's a 16% gain!). It's a shame it's not possible to use MMX registers for memory addressing, and also that MOVD can't transfer the high 32 bits of an MMX register to a general purpose register.
December 2, 2025 at 6:50 PM
I've also tested the IBM 6x86MX at 225 MHz (75×3). It really doesn't like the new MMX column renderer:

Unrolled non-MMX code: 57.460 fps
Rolled 2-pixels-per-loop MMX code: 45.096 fps (-21.5%)

Yikes.
November 27, 2025 at 8:30 PM
Reposted by ViTi95
I HAVE DECODED BURGER KING. I HAVE THE RAW HIGH QUALITY MODELS.

AHAHAHAHAHA
November 26, 2025 at 11:33 AM