PORTIBM PC Portable (uses same BIOS as XT) 42E8 - 8514/A and hardware-compatible video cards Note: supported by S3 chipsets when PORTIBM PC Portable (uses same BIOS as XT) 03D4h register 40h bit 0 is set 42E8w R- Misc. control: Subsystem Status (see #P1018) 42E8w -W Misc. control: Subsystem Control (see #P1019) Bitfields for 8514/A Subsystem Status register: Bit(s) Description (Table P1018) 15-8 (8514/A) reserved 13 (S3) ??? 12-8 (S3) ??? 7 pixel length (0 = four bits, 1 = eight bits) 6-4 reserved 3 FIFO empty (interrupt generated if enabled) 2 FIFO overflow (interrupt generated if enabled) 1 Graphics Engine busy (interrupt generated if enabled) 0 vertical sync (interrupt generated if enabled) SeeAlso: #P1019 Bitfields for 8514/A Subsystem Control Register: Bit(s) Description (Table P1019) 15-14 GP_RESET W 00 no change 01 normal operation 10 reset graphics processor and FIFO 11 reserved 13-12 reserved 11 W enable interrupt when graphics processor idle 10 W enable interrupt on invalid I/O (FIFO overlow) 9 W enable interrupt if inside scissors region 8 W enable vertical blanking interval interrupt 6-4 R monitor ID (8514/A) 7-4 reserved (S3) 3 acknowledge idle interrupt (and clear) 2 acknowledge invalid I/O interrupt (and clear) 1 acknowledge inside-scissors interrupt (and clear) 0 acknowledge vertical blanking interrupt (and clear) SeeAlso: #P1018