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|
;; -----------------------------------------------------------------------
;;
;; 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
|
