mkinitrd-magellan/isolinux/bootsect.inc

;; $Id: bootsect.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
;; -----------------------------------------------------------------------
;;   
;;   Copyright 1994-2005 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.
;;
;; -----------------------------------------------------------------------

;;
;; bootsect.inc
;; 
;; Load a boot sector (or other bootstrap program.)
;;
;; Unlike previous versions of this software, this doesn't require that
;; the length is 512 bytes.  This allows PXE bootstraps and WinNT
;; "CD boot sectors" to be invoked.
;;

;
; Load a boot sector
;
is_bootsector:
%if IS_SYSLINUX || IS_MDSLINUX
		; Transfer zero bytes
		mov byte [CopySuper],0
		jmp short load_bootsec

is_bss_sector:
		; Transfer the superblock
		mov byte [CopySuper],superblock_len
%endif
load_bootsec:
		xchg dx,ax
		shl eax,16
		xchg dx,ax		; Now EAX = file length
		mov edi, 100000h
		mov [trackbuf+4],edi	; Copy from this address
		push edi		; Save load address
		xor dx,dx		; No padding
		call load_high
		call crlf

		sub edi,100000h
		mov [trackbuf+8],edi	; Save length

		mov eax,7C00h		; Entry point
		mov [trackbuf],eax	; Copy to this address
		mov [EntryPoint],eax	; Jump to this address when done

%if IS_SYSLINUX || IS_MDSLINUX
		movzx ecx,byte [CopySuper]
		jcxz .not_bss

		; For a BSS boot sector we have to patch.
		mov esi,superblock
		mov edi,100000h+(superblock-bootsec)
		call bcopy

.not_bss:
%endif

		xor edx,edx
		xor esi,esi
%if IS_SYSLINUX || IS_MDSLINUX || IS_EXTLINUX
		; Restore original FDC table
		mov eax,[OrigFDCTabPtr]
		mov [fdctab],eax

		mov dl,[DriveNumber]
		mov si,PartInfo		; Partition info buffer
		mov di,800h-18		; Put partition info here
		push di
		mov cx,8		; 16 bytes
		xor ax,ax
		rep movsw
		pop si			; DS:SI points to partition info
%elif IS_ISOLINUX
		mov dl,[DriveNo]
%elif IS_PXELINUX
		mov byte [KeepPXE],1	; Chainloading another NBP
		call reset_pxe
%endif
		xor bx,bx

;
; replace_bootstrap for the special case where we have exactly one
; descriptor, and it's the first entry in the trackbuf
;

replace_bootstrap_one:
		push word trackbuf		; Address of descriptor list
		push word 1			; Length of descriptor list
		; Fall through

; 
; Entrypoint for "shut down and replace bootstrap" -- also invoked by
; the COMBOOT API.  This routine expects two words on the stack:
; address of the copy list (versus DS) and count.  Additionally,
; the values of ESI and EDX are passed on to the new bootstrap;
; the value of BX becomes the new DS.
; 
replace_bootstrap:
		;
		; Prepare for shutting down
		;
		call vgaclearmode

		;
		; Set up initial stack frame (not used by PXE if keeppxe is
		; set - we use the PXE stack then.)
		; AFTER THIS POINT ONLY .earlybss IS AVAILABLE, NOT .bss
		;
		xor ax,ax
		mov ds,ax
		mov es,ax		

%if IS_PXELINUX
		test byte [KeepPXE],01h
		jz .stdstack
		les di,[InitStack]	; Reset stack to PXE original
		jmp .stackok
%endif
.stdstack:
		mov di,7C00h-44
		push di
		mov cx,22		; 44 bytes
		rep stosw
		pop di
.stackok:

		mov [es:di+28],edx
		mov [es:di+12],esi
		mov [es:di+6],bx

		pop ax			; Copy list count
		pop bx			; Copy from...

		cli
		mov cx,es
		mov ss,cx
		movzx esp,di

		jmp shuffle_and_boot

%if IS_SYSLINUX || IS_MDSLINUX
		; Nothing
%else
is_bss_sector:
		mov si,err_bssimage
		call cwritestr
		jmp enter_command
%endif
1	niro	532	;; $Id: bootsect.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
2			;; -----------------------------------------------------------------------
3			;;
4			;; Copyright 1994-2005 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			;; bootsect.inc
16			;;
17			;; Load a boot sector (or other bootstrap program.)
18			;;
19			;; Unlike previous versions of this software, this doesn't require that
20			;; the length is 512 bytes. This allows PXE bootstraps and WinNT
21			;; "CD boot sectors" to be invoked.
22			;;
23
24			;
25			; Load a boot sector
26			;
27			is_bootsector:
28			%if IS_SYSLINUX \|\| IS_MDSLINUX
29			; Transfer zero bytes
30			mov byte [CopySuper],0
31			jmp short load_bootsec
32
33			is_bss_sector:
34			; Transfer the superblock
35			mov byte [CopySuper],superblock_len
36			%endif
37			load_bootsec:
38			xchg dx,ax
39			shl eax,16
40			xchg dx,ax ; Now EAX = file length
41			mov edi, 100000h
42			mov [trackbuf+4],edi ; Copy from this address
43			push edi ; Save load address
44			xor dx,dx ; No padding
45			call load_high
46			call crlf
47
48			sub edi,100000h
49			mov [trackbuf+8],edi ; Save length
50
51			mov eax,7C00h ; Entry point
52			mov [trackbuf],eax ; Copy to this address
53			mov [EntryPoint],eax ; Jump to this address when done
54
55			%if IS_SYSLINUX \|\| IS_MDSLINUX
56			movzx ecx,byte [CopySuper]
57			jcxz .not_bss
58
59			; For a BSS boot sector we have to patch.
60			mov esi,superblock
61			mov edi,100000h+(superblock-bootsec)
62			call bcopy
63
64			.not_bss:
65			%endif
66
67			xor edx,edx
68			xor esi,esi
69			%if IS_SYSLINUX \|\| IS_MDSLINUX \|\| IS_EXTLINUX
70			; Restore original FDC table
71			mov eax,[OrigFDCTabPtr]
72			mov [fdctab],eax
73
74			mov dl,[DriveNumber]
75			mov si,PartInfo ; Partition info buffer
76			mov di,800h-18 ; Put partition info here
77			push di
78			mov cx,8 ; 16 bytes
79			xor ax,ax
80			rep movsw
81			pop si ; DS:SI points to partition info
82			%elif IS_ISOLINUX
83			mov dl,[DriveNo]
84			%elif IS_PXELINUX
85			mov byte [KeepPXE],1 ; Chainloading another NBP
86			call reset_pxe
87			%endif
88			xor bx,bx
89
90			;
91			; replace_bootstrap for the special case where we have exactly one
92			; descriptor, and it's the first entry in the trackbuf
93			;
94
95			replace_bootstrap_one:
96			push word trackbuf ; Address of descriptor list
97			push word 1 ; Length of descriptor list
98			; Fall through
99
100			;
101			; Entrypoint for "shut down and replace bootstrap" -- also invoked by
102			; the COMBOOT API. This routine expects two words on the stack:
103			; address of the copy list (versus DS) and count. Additionally,
104			; the values of ESI and EDX are passed on to the new bootstrap;
105			; the value of BX becomes the new DS.
106			;
107			replace_bootstrap:
108			;
109			; Prepare for shutting down
110			;
111			call vgaclearmode
112
113			;
114			; Set up initial stack frame (not used by PXE if keeppxe is
115			; set - we use the PXE stack then.)
116			; AFTER THIS POINT ONLY .earlybss IS AVAILABLE, NOT .bss
117			;
118			xor ax,ax
119			mov ds,ax
120			mov es,ax
121
122			%if IS_PXELINUX
123			test byte [KeepPXE],01h
124			jz .stdstack
125			les di,[InitStack] ; Reset stack to PXE original
126			jmp .stackok
127			%endif
128			.stdstack:
129			mov di,7C00h-44
130			push di
131			mov cx,22 ; 44 bytes
132			rep stosw
133			pop di
134			.stackok:
135
136			mov [es:di+28],edx
137			mov [es:di+12],esi
138			mov [es:di+6],bx
139
140			pop ax ; Copy list count
141			pop bx ; Copy from...
142
143			cli
144			mov cx,es
145			mov ss,cx
146			movzx esp,di
147
148			jmp shuffle_and_boot
149
150			%if IS_SYSLINUX \|\| IS_MDSLINUX
151			; Nothing
152			%else
153			is_bss_sector:
154			mov si,err_bssimage
155			call cwritestr
156			jmp enter_command
157			%endif