Diff of /trunk/mkinitrd-magellan/isolinux/bootsect.inc

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	revision 1132 by niro, Sat Sep 1 22:45:15 2007 UTC	revision 1133 by niro, Thu Aug 19 09:50:43 2010 UTC
#	Line 1	Line 1
	;; $Id: bootsect.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
1	;; -----------------------------------------------------------------------	;; -----------------------------------------------------------------------
2	;;	;;
3	;;   Copyright 1994-2005 H. Peter Anvin - All Rights Reserved	;;   Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
4		;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
5	;;	;;
6	;;   This program is free software; you can redistribute it and/or modify	;;   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	;;   it under the terms of the GNU General Public License as published by
#	Line 13	Line 13
13
14	;;	;;
15	;; bootsect.inc	;; bootsect.inc
16	;;	;;
17	;; Load a boot sector (or other bootstrap program.)	;; Load a boot sector (or other bootstrap program.)
18	;;	;;
19	;; Unlike previous versions of this software, this doesn't require that	;; Unlike previous versions of this software, this doesn't require that
#	Line 25	Line 25
25	; Load a boot sector	; Load a boot sector
26	;	;
27	is_bootsector:	is_bootsector:
28	%if IS_SYSLINUX || IS_MDSLINUX	%if IS_SYSLINUX
29	; Transfer zero bytes	; Transfer zero bytes
30	mov byte [CopySuper],0	push word 0
31	jmp short load_bootsec	jmp short load_bootsec
32
33	is_bss_sector:	is_bss_sector:
34	; Transfer the superblock	; Transfer the superblock
35	mov byte [CopySuper],superblock_len	SuperSize equ $+1
36		push word superblock_len_fat16
37	%endif	%endif
38	load_bootsec:	load_bootsec:
39	xchg dx,ax	mov edi,100000h
	shl eax,16
	xchg dx,ax ; Now EAX = file length
	mov edi, 100000h
40	mov [trackbuf+4],edi ; Copy from this address	mov [trackbuf+4],edi ; Copy from this address
	push edi ; Save load address
41	xor dx,dx ; No padding	xor dx,dx ; No padding
42		mov bx,abort_check ; Don't print dots, but allow abort
43	call load_high	call load_high
	call crlf
44
45	sub edi,100000h	sub edi,100000h
46	mov [trackbuf+8],edi ; Save length	mov [trackbuf+8],edi ; Save length
47
48	mov eax,7C00h ; Entry point	mov eax,7C00h ; Entry point
49	mov [trackbuf],eax ; Copy to this address	mov [trackbuf],eax ; Copy to this address
	mov [EntryPoint],eax ; Jump to this address when done
50
51	%if IS_SYSLINUX || IS_MDSLINUX	%if IS_SYSLINUX
52	movzx ecx,byte [CopySuper]	xor ecx,ecx
53	jcxz .not_bss	pop cx
54
55	; For a BSS boot sector we have to patch.	; For a BSS boot sector we have to patch.
56	mov esi,superblock	mov esi,superblock
57	mov edi,100000h+(superblock-bootsec)	mov edi,100000h+(superblock-bootsec)
58	call bcopy	call bcopy
	.not_bss:
59	%endif	%endif
60		push eax ; Save entry point
61
62	xor edx,edx	xor edx,edx
63	xor esi,esi	xor esi,esi
64	%if IS_SYSLINUX || IS_MDSLINUX || IS_EXTLINUX	%if IS_SYSLINUX || IS_EXTLINUX
65	; Restore original FDC table	; Restore original FDC table
66	mov eax,[OrigFDCTabPtr]	mov eax,[OrigFDCTabPtr]
67	mov [fdctab],eax	mov [fdctab],eax
#	Line 79  load_bootsec:	Line 74  load_bootsec:
74	xor ax,ax	xor ax,ax
75	rep movsw	rep movsw
76	pop si ; DS:SI points to partition info	pop si ; DS:SI points to partition info
77		xor bx,bx
78	%elif IS_ISOLINUX	%elif IS_ISOLINUX
79	mov dl,[DriveNo]	mov dl,[DriveNumber]
80		xor bx,bx
81	%elif IS_PXELINUX	%elif IS_PXELINUX
82	mov byte [KeepPXE],1 ; Chainloading another NBP	mov byte [KeepPXE],03h ; Chainloading + keep PXE
83	call reset_pxe	call reset_pxe
84		lfs si,[InitStack]
85		; Put restore DS, EDX and ESI to the true initial values
86		mov bx,[fs:si+6]
87		mov edx,[fs:si+28]
88		mov esi,[fs:si+12]
89	%endif	%endif
	xor bx,bx
90
91	;	;
92	; replace_bootstrap for the special case where we have exactly one	; replace_bootstrap for the special case where we have exactly one
93	; descriptor, and it's the first entry in the trackbuf	; descriptor, based in low memory.  We will generate a second descriptor
94		; to clear remaining FBM.
95	;	;
96
97	replace_bootstrap_one:	replace_bootstrap_one:
98	push word trackbuf ; Address of descriptor list	mov eax,[trackbuf] ; Base address
99	push word 1 ; Length of descriptor list	add eax,[trackbuf+8] ; Length
100		movzx ecx,word [BIOS_fbm]
101		shl ecx,10 ; Free Base Memory
102		sub ecx,eax
103		mov [trackbuf+12],eax
104		or dword [trackbuf+16],-1 ; Zero memory
105		mov [trackbuf+20],ecx
106		push word 2 ; Length of descriptor list
107	; Fall through	; Fall through
108
109	;	;
110	; Entrypoint for "shut down and replace bootstrap" -- also invoked by	; Entrypoint for "shut down and replace bootstrap" -- also invoked by
111	; the COMBOOT API.  This routine expects two words on the stack:	; the COMBOOT API.  This routine expects the entry point (CS, IP) and the
112	; address of the copy list (versus DS) and count.  Additionally,	; count of the descriptor sequence on the stack; the shuffle
113	; the values of ESI and EDX are passed on to the new bootstrap;	; descriptors start at the first byte of the trackbuf.
114	; the value of BX becomes the new DS.	;
115	;	; The registers EDX and ESI are passed on to the called program,
116		; and BX is passed on as DS.
117		;
118	replace_bootstrap:	replace_bootstrap:
119	;	;
120	; Prepare for shutting down	; Prepare for shutting down
121	;	;
122	call vgaclearmode	call vgaclearmode
123
124		;
125		; We jump here when loading a kernel image, so that we don't reset
126		; the screen mode in "quiet" mode
127		;
128		replace_bootstrap_noclearmode:
129		call cleanup_hardware
130
131	;	;
132	; Set up initial stack frame (not used by PXE if keeppxe is	; Set up initial stack frame (not used by PXE if keeppxe is
133	; set - we use the PXE stack then.)	; set - we use the PXE stack then.)
	; AFTER THIS POINT ONLY .earlybss IS AVAILABLE, NOT .bss
134	;	;
135	xor ax,ax	xor ax,ax
136	mov ds,ax	mov ds,ax
137	mov es,ax	mov es,ax
138
139	%if IS_PXELINUX	%if IS_PXELINUX
140	test byte [KeepPXE],01h	cmp byte [KeepPXE],0
141	jz .stdstack	je .stdstack
142	les di,[InitStack] ; Reset stack to PXE original	les di,[InitStack] ; Reset stack to PXE original
143	jmp .stackok	jmp .stackok
144	%endif	%endif
#	Line 133  replace_bootstrap:	Line 150  replace_bootstrap:
150	pop di	pop di
151	.stackok:	.stackok:
152
153	mov [es:di+28],edx	mov [es:di+28],edx ; New EDX
154	mov [es:di+12],esi	mov [es:di+12],esi ; New ESI
155	mov [es:di+6],bx	mov [es:di+6],bx ; New DS
156
157		%if IS_PXELINUX == 0
158		; DON'T DO THIS FOR PXELINUX...
159		; For PXE, ES:BX -> PXENV+, and this would corrupt
160		; that use.
161
162		; Restore ES:DI -> $PnP (if we were ourselves called
163		; that way...)
164		mov ax,[OrigESDI]
165		mov bx,[OrigESDI+2]
166
167		mov [es:di+8],ax ; New DI
168		mov [es:di+4],bx ; New ES
169		%endif
170		pop ax ; List length
171
172		push di
173		push es
174
175		push ds
176		pop es
177
178		mov ebx,trackbuf
179		imul di,ax,12
180		add di,bx ; DI <- end of list
181		push di
182
183		; Terminating entry...
184		lea eax,[replace_stub] ; Entrypoint
185		push ax
186		stosd
187		xor ax,ax ; EAX[31:16] == 0 already
188		stosd ; 16-bit mode
189		stosd ; End of list
190
191	pop ax ; Copy list count	; Copy the stub
192	pop bx ; Copy from...	pop di
193		mov si,__replacestub_lma
194		mov cx,__replacestub_dwords
195		rep movsd
196
197		xor ecx,ecx
198		pop cx ; ECX <- length of list
199
200		pop word [replace_stub.ss]
201		pop word [replace_stub.esp]
202		pop dword [replace_stub.csip]
203
204	cli	cli
205	mov cx,es	mov ss,[replace_stub.ss]
206	mov ss,cx	mov esp,[replace_stub.esp]
207	movzx esp,di
208		mov edi,trackbuf
209	jmp shuffle_and_boot	mov esi,edi
210
211	%if IS_SYSLINUX || IS_MDSLINUX	jmp shuffle_and_boot_raw
212	; Nothing
213	%else	; This stub gets run after the shuffle.  It is copied
214	is_bss_sector:	; below 0x7c00 in order to properly handle the case
215	mov si,err_bssimage	; of bootstrap replacement.
216	call cwritestr	section .replacestub
217	jmp enter_command	replace_stub:
218	%endif	mov cr0,eax
219		jmp 0:.next
220		.next:
221		mov ax,strict word 0
222		.ss equ $-2
223		mov ss,ax
224		mov esp,strict dword 0
225		.esp equ $-4
226		pop gs
227		pop fs
228		pop es
229		pop ds
230		popad
231		popfd
232		jmp 0:0
233		.csip equ $-4
234
235		section .text

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