Int1Ah AX = B108h(在PCI表面配置空間上，讀取Byte) -- BIOS Int1Ah

READ CONFIGURATION BYTE


Input:
AX = B108h
BH = bus number
BL = device/function number (bits 7-3 device, bits 2-0 function)
DI = register number (0000h-00FFh) (see PCI Configuration Data Format)
Return: 
        CF clear if successful
   CL = byte read
CF set on error
AH = status (00h,87h) (see PCI BIOS v2.0 status codes)
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

BUG:

the Award BIOS 4.51PG (dated 05/24/96) incorrectly returns FFh for register 00h if the PCI function number is nonzero