From 84b526908292b0ab040e6d91ac9cc0812a7f0ba8 Mon Sep 17 00:00:00 2001 From: aybe Date: Sat, 17 Oct 2020 00:56:18 +0200 Subject: [PATCH] [MIGRATED] Delete .\NOTES-TESTING-LOG\2018-07-02\TEST RESULTS AND FINDINGS.TXT NOTE: file deleted after being migrated with original history --- .../2018-07-02/TEST RESULTS AND FINDINGS.TXT | 146 ------------------ 1 file changed, 146 deletions(-) delete mode 100644 NOTES-TESTING-LOG/2018-07-02/TEST RESULTS AND FINDINGS.TXT diff --git a/NOTES-TESTING-LOG/2018-07-02/TEST RESULTS AND FINDINGS.TXT b/NOTES-TESTING-LOG/2018-07-02/TEST RESULTS AND FINDINGS.TXT deleted file mode 100644 index 8fc225e1b..000000000 --- a/NOTES-TESTING-LOG/2018-07-02/TEST RESULTS AND FINDINGS.TXT +++ /dev/null @@ -1,146 +0,0 @@ -2018/07/02 test results and findings. - -Test units: - -COMP-Compro1997 An old Pentium ? from 1997, with ATI AGP VGA -COMP-IBMPS2-30 An old IBM PS/2 Model 30 (286) with VGA -COMP-P2ISA1997 An old Pentium II from 1997, with S3 VGA -COMP-IBM5150 An old IBM 5150, 8088, with CGA -COMP-Old486y91 An old 486SX 33MHz, with Tseng ET4000 -DOSBox-X-1e6bb8dc469761d46217d44615c06a7ff95f2e49 DOSBox-X, by indicated commit -DOSLIB-848166fcacb6292773253273ef192ddae7942064 DOSLIB, by indicated commit - -Equipment: - - - Composite video capture (PEXHDCAP 1080p60). None of my Happauge USB capture - sticks were willing to capture the CGA composite video output for some reason, - nor would the Happauge WinTV in one of my machines. The PEXHDCAP was able to - but had curious brightness problems as screen contents changed. - - - HDMI video capture (PEXHDCAP 1080p30) - - - VGA to HDMI adapter (one that matches the mode and converts as-is) - - - A mobile phone, pointed at the LCD TV set (second try, IBM 5150 test) - -Software: - - - DOSBox-X build: - git commit 1e6bb8dc469761d46217d44615c06a7ff95f2e49 - - - DOSLIB build: - git commit 848166fcacb6292773253273ef192ddae7942064 - -Findings: - - - On the IBM 5150, The IBM BIOS (I think it dates from 1982) is indeed missing - the "number of rows - 1" value in the BIOS data area. This confirms comments - in TEST-FW\VIDEO\PC\TEST.C about how it may not exist according to the - definitions listed in IBM ROM BIOS source code from 1984, while the 1986 - listing does list it. - - - On the IBM 5150, INT 10h appears to have a bug where all CGA modes work, but - setting mode 7 produces a video mode with horizontal and vertical timing that - is incompatible with NTSC. During that part, neither my capture card nor the - LCD TV set would display anything. - - Perhaps the bug, theoretically, is the application of MDA monitor timing for - INT 10h mode 7 even on CGA. - - - The EGA palette assumed in 16-color modes didn't always match the TEST-FW - video's assumptions, but the differences are not jarring. They're understandable. - - - In the 256-color mode test, three different attribute controller to DAC to - DAC mask behaviors were seen. - - - The most common, seen on all but two, is that the attribute controller appears - to affect both the low nibble and upper bits (high nibble?) of the 8-bit - color palette index. - - When the test program flashes the attribute controller palette #1 for example, - it appears to affect not only every 16th color starting from #1, but also - colors #16-#31. - - Generally, flashing attribute controller palette N affects: - Every 16th color starting at N - Colors (N * 16) to (N * 16 + 15) - - This remapping needs more investigation on how exactly it works. This should - be done as a separate palette test program targeting only the VGA. - - Results so far suggest that both the low nibble and high nibble are translated - through the attribute controller palette registers. - - - On the Tseng ET4000, the attribute controller only affects the low 4 bits. - It does not affect any of the higher bits. - - Flashing attribute color palette N affects only every 16th color starting at N. - - - Finally, perhaps the most erroneous is DOSBox-X (and DOSBox SVN). - - Due to optimizations around lazily updating only part of the color palette, - DOSBox-X only updates ONE color palette entry when the attribute controller - palette is flashing. - - Flashing attribute controller palette N affects: - One color at DAC palette entry N - -Questions to answer in further development: - - For a separate program in TEST-FW\VIDEO\PC, focused on the VGA: - - - How exactly does the attribute controller affect all 8 bits of 256-color pixels? - - The TEST-FW\VIDEO\PC\TEST.C program only shows what happens when flashing the - attribute controller palette entry between it's initial value and 0x3F (if the - initial value is dimmer than neutral gray) or 0x00 (if brigher than gray). - - - How do Attribute Controller registers 0x10 and 0x14 affect this mapping? - - See http://www.osdever.net/FreeVGA/vga/attrreg.htm - - These registers are documented to affect the color palette entry coming from - the attribute controller, bits 4-5 in one case, and bits 6-7 in non-256-color - modes. - - Interesting to check: What happens if register 0x10 bit 6 (8-bit color enable) - is switched off in 256-color mode? - - - How does the DAC mask (3C6h) affect the attribute controller, VGA palette, - various AC bits? - - It's not clear where the DAC mask is applied, though as "Pel mask" it may be - at the final stage before conversion through the VGA palette. Test program - should confirm this. - - Test routine ideas: - - - Interactive mode to fiddle with attribute controller, color palette, and - attribute controller bits, with 256-color palette on screen to show effects. - - - Non-interactive mode to run through combinations of these bits, for capture - and logging purposes. - -Related demoscene capture ideas: - - "Copper" (ftp.scene.org/pub/parties/1992/theparty92/demo/copper.zip) - - - This demo uses VGA palette tricks that only seem to work in DOSBox-X and - are said only to work on Tseng ET4000AX cards. - - Test on ET4000 card vs S3 and ATI to note where it works exactly. - - Noted in the past is that on S3 and Paradise chipsets, the "line fading" - effects (explicitly said and during scrolling credits) show absolutely - nothing on-screen. - - - This demo abuses the horizontal sync pulse in some parts to make the - picture "wobble", which causes modern VGA monitors and LCDS to switch off - instead. Pull out an old VGA CRT or two and see if the effect can be - recorded off the screen. Noted in past test runs, is that the effect - makes an audible though quiet "ringing" sound in the back of the picture - tube as the CRT tries to follow this "wobble" effect. -