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psx:gpu [2012/10/23 13:00] amidog created |
psx:gpu [2013/08/25 21:38] (current) amidog |
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| + | ====== GPU Version ====== | ||
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| + | There are atleast two different GPU versions, the old v0 one used in early SCPH-100x models, and the new v2 one used in later models. Here are the differences and/or issues I have observed. | ||
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| + | ^ ^Old ^New ^Note ^ | ||
| + | |Status after reset|<code>0x14800000</code>|<code>0x14802000</code>|-| | ||
| + | |Modulate|<code>((color & 0xf8) * (texel << 3)) >> 7</code>|<code>(color * (texel << 3)) >> 7</code>|In old GPU, the least significant bits are ignored.| | ||
| + | |Drawing area|9-bit (max 511) vertically|10-bit (max 1023) vertically|The new GPU seems to support 2MB VRAM.| | ||
| + | |GPU info|8 possible results, version = 0|16 possible results, version = 2|-| | ||
| + | |Framebuffer rectangle (0x02)|There is an "interesting" bug when <code>(x_pos & 15) == 15</code>|-|Bug has been fixed in new GPU.| | ||
| + | |VRAM move (0x80)|-|Large moves will make the GPU freeze|I haven't observed any VRAM move freezes on the old GPU while I can repeatedly freeze the new GPU by issuing one or two large VRAM moves.| | ||
| + | |Sprite X/Y-flip (mirror)|N/A|Supported|-| | ||
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| ====== Resolution ====== | ====== Resolution ====== | ||
