Attachment 61349 Details for Bug 140119

[patch] make syslinux detect byte-swapped cpio archives

syslinux-gfxboot-cpio-swab.diff (text/plain), 1.42 KB, created by Colin Watson on 2005-12-19 11:00:06 UTC

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Creator: Colin Watson

Created: 2005-12-19 11:00:06 UTC

Size: 1.42 KB

patch

obsolete

>diff -u syslinux-3.11/gfxboot.inc syslinux-3.11/gfxboot.inc
>--- syslinux-3.11/gfxboot.inc
>+++ syslinux-3.11/gfxboot.inc
>@@ -286,6 +286,7 @@
> ; != 0 -> graphics active
> gfx_ok			db 0
> gfx_cwritestr_old	db 0c3h		; 'ret'
>+gfx_cpio_swab		db 0
> 
> gfx_mem_start_seg	dw 0
> gfx_mem_end_seg		dw 0
>@@ -920,15 +921,26 @@
> 
> 		lin2segofs edi,es,bx
> 		cmp word [es:bx],71c7h
>+		jz find_file_30			; normal cpio record
>+		cmp word [es:bx],0c771h		; maybe byte-swapped?
> 		jnz find_file_90		; no cpio record
>+		mov byte [gfx_cpio_swab],1
> 
>-		movzx esi,word [es:bx+20]	; file name size
>+find_file_30:
>+		mov ax,[es:bx+20]		; file name size
>+		call cpio_swab
>+		movzx esi,ax
> 
> 		inc si
> 		and si,~1			; align
> 
>-		mov ecx,[es:bx+22]		; data size
>-		rol ecx,16			; get word order right
>+		mov ax,[es:bx+22]		; data size, MSW
>+		call cpio_swab
>+		mov cx,ax
>+		shl ecx,16
>+		mov ax,[es:bx+24]		; data size, LSW
>+		call cpio_swab
>+		mov cx,ax
> 
> 		inc ecx
> 		and ecx,byte ~1			; align
>@@ -950,6 +962,23 @@
> 
> ; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> ;
>+; byte-swap cpio data if appropriate
>+;
>+; ax:		word to swap
>+;
>+; return:	ax: swapped if [gfx_cpio_swab], otherwise same as input
>+;
>+cpio_swab:
>+		cmp byte [gfx_cpio_swab],0
>+		jz cpio_swab_90
>+		xchg ah,al
>+
>+cpio_swab_90:
>+		ret
>+
>+
>+; - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>+;
> ;  es:bx	file start
> ;
> ;  return:	eax:	offset to code entry

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Attachments on bug 140119: 61349 | 61350 | 61351