pci16.inc

MenuetOS是一个用汇编开发的32/64位PC操作系统

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;;                                                           ;;
;;  PCI16.INC                                                ;;
;;                                                           ;;
;;  16 bit PCI driver code                                   ;;
;;  Version 0.2  December 21st, 2002                         ;;
;;  Author: Victor Prodan, [e-mail]            ;;
;;                                                           ;;
;;  See file COPYING for details                             ;;
;;                                                           ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

init_pci_16:

    pushad

    xor ax,ax
    mov es,ax
    mov byte [es:0x9020],1 ;default mechanism:1
    mov ax,0xb101
    int 0x1a
    or ah,ah
    jnz pci16skip

    mov [es:0x9021],cl ;last PCI bus in system
    mov [es:0x9022],bx
    mov [es:0x9024],edi

; we have a PCI BIOS, so check which configuration mechanism(s)
; it supports
; AL = PCI hardware characteristics (bit0 => mechanism1, bit1 => mechanism2)

    test al,1
    jnz pci16skip
    test al,2
    jz pci16skip
    mov byte [es:0x9020],2 ; if (al&3)==2 => mechanism 2

pci16skip:

    mov ax,0x1000
    mov es,ax

    popad