PORTIBM PC Portable (uses same BIOS as XT) 4AE8-4AE9 - 8514/A and compatible - CRT CONTROL Notes: supported by ATI Mach8 and Mach32 chipsets supported by S3 chipsets when PORTIBM PC Portable (uses same BIOS as XT) 03D4h register 40h bit 0 is set SeeAlso: #P0749 4AE8w -W CRT control: Advanced function control (see also #P1022) (02h = VGAVideo Graphics Array(Video Graphics Array) The video adapter introduced with the IBMInternational Busiuness Machines PS/2IBM PS/2, any model series of computers. mode, 03h = 480-line mode, 07h = 768-line mode) Bitfields for S3 8514/A-compatible Advanced Function Control register: Bit(s) Description (Table P1022) 15-7 reserved 6 (928 only) enable Write Posting 5 (928+) enable memory-mapped I/O 4 (928+) enable linear addressing (see also #P0741) 3 reserved 2 (911-928) screen size (1 = 800x600 or 1024x768, 0=640x480) (Trio32/Trio64) enhanced modes pixel length (0 = 8+ bpp, 1 = 4 bpp) 1 reserved (1) 0 enable enhanced functions Note: bit 4 is ORed with CR58 bit 4; bit 5 is ORed with CR53 bit 4