;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; RDOS operating system
; Copyright (C) 1988-2000, Leif Ekblad
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version. The only exception to this rule
; is for commercial usage in embedded systems. For information on
; usage in commercial embedded systems, contact embedded@rdos.net
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, write to the Free Software
; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
;
; The author of this program may be contacted at leif@rdos.net
;
; ACPIBASE.ASM
; Basic ACPI support functions not available from RDOS device-driver interface
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

INCLUDE ..\..\kernel\user.def
INCLUDE ..\..\kernel\os.def
INCLUDE ..\..\kernel\os.inc
INCLUDE ..\..\kernel\user.inc
INCLUDE ..\..\kernel\driver.def
INCLUDE ..\..\kernel\os\system.def

    .386p

_TEXT    SEGMENT byte public 'CODE'

    assume cs:_TEXT

      
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;       
;
;           NAME:           CheckRsdp
;
;           DESCRIPTION:    Check for an RSDP
;
;       PARAMETERS:     DS:SI       Base address to check
;
;       RETURNS:    NC      OK
;               EAX     Physical address
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

rsd1 DB 'RSD '
rsd2 DB 'PTR '

CheckRsdp   Proc near
    mov eax,dword ptr cs:rsd1
    cmp eax,[si]
    jne check_rsdp_fail
;
    mov eax,dword ptr cs:rsd2
    cmp eax,[si+4]
    jne check_rsdp_fail
;
    push cx
    push si
;    
    xor al,al    
    mov cx,20

check_rsdp_loop:
    add al,[si]
    inc si
    loop check_rsdp_loop
;
    pop si
    pop cx    
;
    or al,al
    jnz check_rsdp_fail
;
    clc
    jmp check_rsdp_done

check_rsdp_fail:
    stc

check_rsdp_done:    
    ret
CheckRsdp   Endp
      
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;       
;
;       NAME:           GetRsdp
;
;       DESCRIPTION:    Get the RSDP
;
;       RETURNS:        EAX     Physical address or 0
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

    public AcpiOsGetRootPointer_
    
AcpiOsGetRootPointer_ Proc near
    push ds
    push es
    push ebx
    push ecx
    push edx
    push esi
    push edi
    push bp
;
    mov eax,1000h
    AllocateBigLinear
    AllocateGdt
    mov ecx,1000h
    CreateDataSelector16
    mov eax,7h
    SetPhysicalPage
    mov ds,bx    
;    
    mov esi,40Eh
    mov si,[si]
    movzx esi,si
    shl esi,4
;
    mov eax,esi
    and ax,0F000h
    or al,7
    SetPhysicalPage
    and si,0FFFh
;    
    mov cx,40h

get_rsdp_bda:
    call CheckRsdp
    jnc get_rsdp_ok
;
    add si,10h
    loop get_rsdp_bda
;     
    mov edi,0E0000h
    mov bp,20h

get_rsdp_bios:
    mov eax,edi
    and ax,0F000h
    or al,7
    SetPhysicalPage
;
    mov esi,edi
    and si,0FFFh
;
    mov cx,100h

get_rsdp_bios_page:
    call CheckRsdp
    jnc get_rsdp_ok
;    
    add si,10h
    loop get_rsdp_bios_page
;
    add edi,1000h
    sub bp,1
    jnz get_rsdp_bios
;
    xor eax,eax
    jmp get_rsdp_done

get_rsdp_ok:
    GetPhysicalPage
    and ax,0F000h
    or ax,si

get_rsdp_done:  
    push eax
    xor eax,eax
    mov ds,ax
    SetPhysicalPage
    mov ecx,1000h
    FreeLinear
    FreeGdt    
    pop eax
;    
    pop bp
    pop edi
    pop esi
    pop edx
    pop ecx
    pop ebx
    pop es
    pop ds
    ret
AcpiOsGetRootPointer_ Endp

_TEXT    ENDS

    END