INT 1A - PCI BIOS(Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly. v2.0c+ - READ CONFIGURATION DWORDDoubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address. (VLSI devices) AX = B10Ah subfn 1004h BH = bus number BL = device/function number (bits 7-3 device, bits 2-0 function) DI = register number (0000h-00FFh) (see #00878) Return: CF clear if successful ECX = dword read CF set on error AH = status (00h,87h) (see #00729) EAX, EBX, ECX, and EDX may be modified all other flags (except IF) may be modified Notes: this function may require up to 1024 byte of stack; it will not enable interrupts if they were disabled before making the call the meanings of BL and BH on entry were exchanged between the initial drafts of the specification and final implementation SeeAlso: AX=B10Ah,AX=B10Ah/SF=8086h Format of PCI Configuration Data for VLSI VL82C591 Host/PCI bridge: Offset Size Description (Table 00919) 00h 64 BYTEs header (see #00878) (vendor ID 1004h, device ID 0005h) 40h BYTE bus number 41h BYTE subordinate bus number 42h WORD reserved 44h 4 DWORDs reserved 54h 2 BYTEs device-specific configuration registers 56h WORD reserved 58h 2 BYTEs device-specific configuration registers 5Ah WORD reserved 5Ch 5 BYTEs device-specific configuration registers ... FFh BYTE device-specific configuration register SeeAlso: #00878,#00732,#00920 Format of PCI Configuration data for VLSI VL82C593 PCI/ISA(Industry-Standard Architecture) The expansion bus used by the IBMInternational Busiuness Machines PCIBM PC/ATIBM PC AT. See also EISA. bridge: Offset Size Description (Table 00920) 00h 64 BYTEs header (see #00878) (vendor ID 1004, device ID 0006h) 40h 4 DWORDs reserved 50h 11 BYTEs device-specific configuration registers 5Bh BYTE reserved 5Ch 25 BYTEs device-specific configuration registers 75h 138 BYTEs reserved FFh BYTE device-specific configuration register SeeAlso: #00878,#00919