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205 lines
7.0 KiB
HTML
<html><head>
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<meta http-equiv="content-type" content="text/html; charset=windows-1252">
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<title>video information</title>
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<style>@media print {#ghostery-purple-box {display:none !important}}</style></head>
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<body><pre></pre>
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<h2 align="Center">Video Information Tables</h2>
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<pre>
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<b> BIOS Data Area Fields</b>
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<b> Address Size Description</b>
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40:49 byte Current video mode (see <a href="http://stanislavs.org/helppc/int_10-0.html">VIDEO MODE</a>)
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40:4A word Number of screen columns
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40:4C word Size of video regen buffer in bytes
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40:4E word Starting address in video regen buffer (offset)
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40:50 8 words Cursor position of pages 1-8, high order
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byte=row, low order byte=column
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40:60 byte Ending (bottom) scan line for cursor
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40:61 byte Starting (top) scan line for cursor
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40:62 byte Active display page number
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40:63 word Base port address for active <a href="http://stanislavs.org/helppc/6845.html">6845</a> CRT controller
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3B4h = mono, 3D4h = color
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40:65 byte 6845 CRT mode control register value (port 3x8h)
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EGA/VGA values emulate those of the MDA/CGA
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40:66 byte CGA current color palette setting (port 3d9h)
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EGA and VGA values emulate the CGA
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40:84 byte Rows on the screen (less 1, EGA+)
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40:85 word Point height of character matrix (EGA+)
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40:87 byte Video mode options (EGA+)
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|7|6|5|4|3|2|1|0| Video mode options (EGA+)
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| | | | | | | `-- 1=alphanumeric cursor emulation enabled
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| | | | | | `--- 1=video subsystem attached to monochrome
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| | | | | `---- reserved
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| | | | `----- 1=video subsystem is inactive
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| | | `------ reserved
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| `--------- video RAM 00-64K 10-192K 01-128K 11-256K
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`---------- video mode number passed to <a href="http://stanislavs.org/helppc/int_10.html">INT 10</a>, function 0
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40:88 byte EGA feature bit switches, emulated on VGA
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|7|6|5|4|3|2|1|0| EGA feature bit switches (EGA+)
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| | | | | | | `-- EGA SW1 config (1=off)
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| | | | | | `--- EGA SW2 config (1=off)
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| | | | | `---- EGA SW3 config (1=off)
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| | | | `----- EGA SW4 config (1=off)
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| | | `------ Input FEAT0 (ISR0 bit 5) after output on FCR0
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| | `------- Input FEAT0 (ISR0 bit 6) after output on FCR0
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| `-------- Input FEAT1 (ISR0 bit 5) after output on FCR1
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`--------- Input FEAT1 (ISR0 bit 6) after output on FCR1
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40:89 byte Video display data area (MCGA and VGA)
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|7|6|5|4|3|2|1|0| Video display data area (MCGA and VGA)
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| | | | | | | `-- 1=VGA is active
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| | | | | | `--- 1=gray scale is enabled
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| | | | | `---- 1=using monochrome monitor
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| | | | `----- 1=default palette loading is disabled
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| | | `------ see table below
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| | `------- reserved
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| `-------- 1=display switching enabled
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`--------- alphanumeric scan lines (see table below)
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<b> Bit7 Bit4 Scan Line information</b>
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0 0 350 line mode
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0 1 400 line mode
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1 0 200 line mode
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1 1 reserved
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40:8A byte Display Combination Code (DCC) table index (EGA+)
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40:A8 dword BIOS Video Save/Override Pointer Table address
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</pre>
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<h2 align="Center">EGA / VGA Related Tables</h2>
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<pre>
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<b> Video Save/Override Pointer Table (pointer at 40:A8):</b>
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00 dword Video Parameter Table pointer
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04 dword Dynamic Parameter Save Area pointer (EGA, VGA)
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08 dword Alphanumeric Character Set Override pointer
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0C dword Graphics Character Set Override pointer
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10 dword Secondary Save Pointer Table pointer (VGA)
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14 dword reserved, set to 0000:0000
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18 dword reserved, set to 0000:0000
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<b> Video Parameter Table</b>
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00 byte number of displayed character columns
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01 byte number of displayed screen rows minus 1
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02 byte character matrix height in points
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03 word video buffer size in bytes
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05 dword contents of sequencer registers 1-4
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09 byte misc. output register values
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0A 25bytes contents of CRTC registers 0-18h
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23 20bytes contents of attribute controller regs 0-13h
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37 9 bytes contents of graphics controller regs 0-8
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<b> Dynamic Parameter Save Area</b>
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00 16bytes contents of graphics controller pallette regs
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10 byte contents of graphics controller overscan reg
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11 239bytes reserved
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<b> Alphanumeric Character Set Override</b>
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00 byte length of each character definition in bytes
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01 byte character generator RAM bank
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02 word count of characters defined
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04 word first character code in table
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06 dword pointer to character font definition table
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0A byte number of character rows displayed
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0B nbytes array of applicable video modes
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0B+n byte FFh end of mode list marker
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<b> Graphics Character Set Override</b>
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00 byte count of displayed character rows
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01 word length of each character definition in bytes
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03 dword pointer to character font definition table
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07 nbytes array of applicable video modes
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07+n byte FFh end of mode list marker
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<b> Secondary Save Pointer Table</b>
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00 word length of table in bytes
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02 dword pointer to display combination code table
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06 dword pointer to secondary alphanumeric char set override
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0A dword pointer to user palette profile table (VGA)
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0E dword reserved
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12 dword reserved
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16 dword reserved
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<b> Display Combination Code Table</b>
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00 byte number of table entries
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01 byte DCC table version number
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02 byte maximum display type code
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03 byte reserved
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04 n words array valid display combinations:
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0,0 entry 0 no display
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0,1 entry 1 MDPA
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0,2 entry 2 CGA
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2,1 entry 3 MDPA + CGA
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0,4 entry 4 EGA
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4,1 entry 5 EGA + MDPA
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0,5 entry 6 MEGA
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2,5 entry 7 MEGA + CGA
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0,6 entry 8 PGC
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1,6 entry 9 PGC + MDPA
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5,6 entry 10 PGC + MEGA
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0,8 entry 11 CVGA
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1,8 entry 12 CVGA + MDPA
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0,7 entry 13 MVGA
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2,7 entry 14 MVGA + CGA
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2,6 entry 15 MVGA + PGC
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<b> Secondary Alpha Mode Auxillary Character Generator Table</b>
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00 byte bytes per character
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01 byte block to load
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02 byte reserved
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03 dword font table pointer
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07 nbytes array of mode values for this font
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07+n byte FFh end of mode list marker
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<b> Palette Profile Table (VGA only)</b>
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00 byte 1 - enable underlining in all alphanumeric modes
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0 - enable underlining in monochrome alpha modes
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-1 - disable underlining in all alpha modes
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01 byte reserved
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02 word reserved
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04 word count of attribute controller regs in table
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06 word first attribute controller register number
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08 dword pointer to attribute controller reg table
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0C word count of video DAC color registers in table
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0E word first video DAC color register number
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10 dword video DAC color register table pointer
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14 nbytes array of applicable video modes for this font
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14+n byte FFh end of video mode list marker
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- see also <a href="http://stanislavs.org/helppc/bios_data_area.html">BIOS Data Area</a>
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- see <a href="http://stanislavs.org/helppc/int_10-1b.html">INT 10,1B</a> for Dynamic Video State Table and Video Static
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Functionality Table
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</pre>
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