en:docs:bios:api:int10:00

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Note: This IBM PC BIOS API call is for DOS/Win16 personality only. Use Family API for portability.

Note: osFree Macro Library provides macros for most of functions

2022/03/13 05:41 · prokushev · 0 Comments

Int 10H, AH=00H

Version

IBM 5150 and higher

Brief

Specify the display mode for the currently active display adapter

Macro

Family API

Input

  • AH = 00h
  • AL = Mode

Return

  • AL = video mode flag (Phoenix, AMI BIOS)
    • 20h mode > 7
    • 30h modes 0-5 and 7
    • 3Fh mode 6
  • AL = CRT controller mode byte (Phoenix 386 BIOS v1.10)

Notes

  • Install check/adapter detect:
    • for Ahead adapters, the signature “AHEAD” at C000h:0025h
    • for Paradise adapters, the signature “VGA=” at C000h:007Dh
    • for Oak Tech OTI-037/057/067/077 chipsets, the signature “OAK VGA” at C000h:0008h
    • for ATI adapters, the signature “761295520” at C000h:0031h; the byte
      • at C000h:0043h indicates the chipset revision:
        • 31h for 18800
        • 32h for 18800-1
        • 33h for 18800-2
        • 34h for 18800-4
        • 35h for 18800-5
        • 62h for 68800AX (Mach32) (see also #00732)
      • the two bytes at C000h:0040h indicate the adapter type
        • “22” EGA Wonder
        • “31” VGA Wonder
        • “32” EGA Wonder800+
      • the byte at C000h:0042h contains feature flags
        • bit 1: mouse port present
        • bit 4: programmable video clock
      • the byte at C000h:0044h contains additional feature flags if chipset
        • byte > 30h (see #00009)
    • for Genoa video adapters, the signature 77h XXh 99h 66h at C000h:NNNNh, where NNNNh is stored at C000h:0037h and XXh is
      • 00h for Genoa 6200/6300
      • 11h for Genoa 6400/6600
      • 22h for Genoa 6100
      • 33h for Genoa 5100/5200
      • 55h for Genoa 5300/5400
    • for SuperEGA BIOS v2.41+, C000h:0057h contains the product level
    • for Genoa SuperEGA BIOS v3.0+, C000h:0070h contains the signature “EXTMODE”, indicating support for extended modes
  • IBM standard modes do not clear the screen if the high bit of AL is set (EGA or higher only)
  • the Tseng ET4000 chipset is used by the Orchid Prodesigner II, Diamond SpeedSTAR VGA, Groundhog Graphics Shadow VGA, Boca Super X VGA, Everex EV-673, etc.
  • intercepted by GRAFTABL from Novell DOS 7 and Caldera OpenDOS 7.01.

Note