mkinitrd-magellan/isolinux/cpuinit.inc

;; $Id: cpuinit.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
;; -----------------------------------------------------------------------
;;   
;;   Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
;;
;;   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, Inc., 53 Temple Place Ste 330,
;;   Boston MA 02111-1307, USA; either version 2 of the License, or
;;   (at your option) any later version; incorporated herein by reference.
;;
;; -----------------------------------------------------------------------

;;
;; cpuinit.inc
;; 
;; CPU-dependent initialization and related checks.
;;

check_escapes:
		mov ah,02h			; Check keyboard flags
		int 16h
		mov [KbdFlags],al		; Save for boot prompt check
		test al,04h			; Ctrl->skip 386 check
		jnz skip_checks

;
; Now check that there is sufficient low (DOS) memory
;
; NOTE: Linux doesn't use all of real_mode_seg, but we use the same
; segment for COMBOOT images, which can use all 64K
;
dosram_k	equ (real_mode_seg+0x1000) >> 6	; Minimum DOS memory (K)
		int 12h
		cmp ax,dosram_k
		jae enough_ram
		mov si,err_noram
		call writestr
		jmp kaboom
enough_ram:
skip_checks:

;
; Initialize the bcopy32 code in low memory
;
		mov si,section..bcopy32.start
		mov di,__bcopy_start
		mov cx,__bcopy_size >> 2
		rep movsd

;
; Check if we're 386 (as opposed to 486+); if so we need to blank out
; the WBINVD instruction
;
; We check for 486 by setting EFLAGS.AC
;
%if DO_WBINVD
		pushfd				; Save the good flags
		pushfd
		pop eax
		mov ebx,eax
		xor eax,(1 << 18)		; AC bit
		push eax
		popfd
		pushfd
		pop eax
		popfd				; Restore the original flags
		xor eax,ebx
		jnz is_486
;
; 386 - Looks like we better blot out the WBINVD instruction
;
		mov byte [try_wbinvd],0c3h		; Near RET
is_486:
%endif	; DO_WBINVD

1	niro	532	;; $Id: cpuinit.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
2			;; -----------------------------------------------------------------------
3			;;
4			;; Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
5			;;
6			;; This program is free software; you can redistribute it and/or modify
7			;; it under the terms of the GNU General Public License as published by
8			;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9			;; Boston MA 02111-1307, USA; either version 2 of the License, or
10			;; (at your option) any later version; incorporated herein by reference.
11			;;
12			;; -----------------------------------------------------------------------
13
14			;;
15			;; cpuinit.inc
16			;;
17			;; CPU-dependent initialization and related checks.
18			;;
19
20			check_escapes:
21			mov ah,02h ; Check keyboard flags
22			int 16h
23			mov [KbdFlags],al ; Save for boot prompt check
24			test al,04h ; Ctrl->skip 386 check
25			jnz skip_checks
26
27			;
28			; Now check that there is sufficient low (DOS) memory
29			;
30			; NOTE: Linux doesn't use all of real_mode_seg, but we use the same
31			; segment for COMBOOT images, which can use all 64K
32			;
33			dosram_k equ (real_mode_seg+0x1000) >> 6 ; Minimum DOS memory (K)
34			int 12h
35			cmp ax,dosram_k
36			jae enough_ram
37			mov si,err_noram
38			call writestr
39			jmp kaboom
40			enough_ram:
41			skip_checks:
42
43			;
44			; Initialize the bcopy32 code in low memory
45			;
46			mov si,section..bcopy32.start
47			mov di,__bcopy_start
48			mov cx,__bcopy_size >> 2
49			rep movsd
50
51			;
52			; Check if we're 386 (as opposed to 486+); if so we need to blank out
53			; the WBINVD instruction
54			;
55			; We check for 486 by setting EFLAGS.AC
56			;
57			%if DO_WBINVD
58			pushfd ; Save the good flags
59			pushfd
60			pop eax
61			mov ebx,eax
62			xor eax,(1 << 18) ; AC bit
63			push eax
64			popfd
65			pushfd
66			pop eax
67			popfd ; Restore the original flags
68			xor eax,ebx
69			jnz is_486
70			;
71			; 386 - Looks like we better blot out the WBINVD instruction
72			;
73			mov byte [try_wbinvd],0c3h ; Near RET
74			is_486:
75			%endif ; DO_WBINVD
76