GPU Polyline Over DMA: Difference between revisions
| Revision as of 05:11, 23 October 2026 RemmyLee (Hardware tests: 72 more test pages, listed on the main page by area; RUN.toml no longer published) | Revision as of 05:18, 23 October 2026 RemmyLee (Hardware tests: nine DMA, MDEC and BIOS test pages with part names for titles; join one-sentence paragraphs per voice.md) | ||
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| A polyline command ends at the end word 55555555h. The probes send polylines through DMA2 in list mode with that word missing, misplaced or in a colour slot. An 8 x 4 tile follows in a later node. Each case reports which points were drawn, whether two test pixels at (51,30) and (58,30) and the tile were drawn, and GPUSTAT, CHCR and MADR when DMA hung.[^run2] | A polyline command ends at the end word 55555555h. The probes send polylines through DMA2 in list mode with that word missing, misplaced or in a colour slot. An 8 x 4 tile follows in a later node. Each case reports which points were drawn, whether two test pixels at (51,30) and (58,30) and the tile were drawn, and GPUSTAT, CHCR and MADR when DMA hung.[^run2] | ||
| − | The flat polyline is GP0(48h) with 18 white points. Point i has x equal to i. Its y is 2 for even i and 10 for odd i. SXPRING runs cases 1 and 2, and SXPRING2 runs all four.[^run2] | + | The flat polyline is GP0(48h) with 18 white points. Point i has x equal to i. Its y is 2 for even i and 10 for odd i. SXPRING runs cases 1 and 2, and SXPRING2 runs all four.[^run2] The [GP0 drawing commands](/hardware/gpu/gp0-drawing/) page describes the command and the [DMA](/hardware/dma/) page describes list mode. |
| − | The [GP0 drawing commands](/hardware/gpu/gp0-drawing/) page describes the command and the [DMA](/hardware/dma/) page describes list mode. | ||
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| ## Results | ## Results | ||
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| In case 1 point 2 was not drawn, and both test pixels (51,30) and (58,30) were lit.[^run1][^run2] | In case 1 point 2 was not drawn, and both test pixels (51,30) and (58,30) were lit.[^run1][^run2] | ||
| − | A flat polyline node that ends with no end word leaves GPUSTAT bits 25 to 28 at 0, and DMA2 waits at the next node. GPUSTAT read 40802400h in every hung case.[^run2] | + | A flat polyline node that ends with no end word leaves GPUSTAT bits 25 to 28 at 0, and DMA2 waits at the next node. GPUSTAT read 40802400h in every hung case.[^run2] In a Gouraud polyline, 55555555h in a colour slot is taken as a colour and does not end the line, so case 4 drew its three points and the tile.[^run2] |
| − | In a Gouraud polyline, 55555555h in a colour slot is taken as a colour and does not end the line, so case 4 drew its three points and the tile.[^run2] | ||
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| ## Runs | ## Runs | ||