could bootblock guru's look at this?

[Julian Elischer]

John Baldwin wrote:

>On Sunday 12 December 2004 01:00 am, Julian Elischer wrote:
>  
>
>>We need to decide what to do with this PR
>>    
>>
>
>I just don't like loosing the bell but I guess it can go in.  It also needs to 
>be merged into boot0ext.S, but that wouldn't have to lose the bell as that 
>version has more room for code.
>  
>
Peter Edwards has made a reply to kern/66248 that saves enough bytes to 
allow us to keep the bell.
could you look at that?

thanks.

>  
>
>>-------- Original Message --------
>>Subject: Re: kern/66248: [panic] bootloader is confused by booting from USB
>>flash, trashes main drives boot block
>>Date: Mon, 8 Nov 2004 17:20:21 GMT
>>From: Hans Petter Selasky <hselasky at c2i.net>
>>Reply-To: Hans Petter Selasky <hselasky at c2i.net>
>>To: freebsd-usb at freebsd.org
>>
>>The following reply was made to PR kern/66248; it has been noted by GNATS.
>>
>>From: Hans Petter Selasky <hselasky at c2i.net>
>>To: jhb at freebsd.org, freebsd-gnats-submit at freebsd.org, bremner at unb.ca
>>Cc:
>>Subject: Re: kern/66248: [panic] bootloader is confused by booting from USB
>>flash, trashes main drives boot block
>>Date: Mon, 8 Nov 2004 18:24:03 +0100
>>
>>  --SUOF0GtieIMvvwua
>>  Content-Type: text/plain; charset=us-ascii
>>  Content-Disposition: inline
>>
>>  Hi,
>>
>>  Attached patch for /src/sys/boot/i386/boot0/boot0.S closes kern/66248
>>  Apply using: cat boot0.S.diff | patch -N -l
>>
>>
>>  When the boot0 boot-manager is used on a floppy or USB drive, the
>>floppy's or USB's boot-sector gets written to the hdd!
>>
>>  Solution: Only update the boot-sector when there is a valid drive number
>>or the drive number is set manually.
>>
>>  To make the patch fit into the code I had to disable the "beep-signal".
>>
>>  Yours
>>  -HPS
>>
>>
>>  --SUOF0GtieIMvvwua
>>  Content-Type: text/plain; charset=us-ascii
>>  Content-Disposition: attachment; filename="boot0.S.diff"
>>
>>  *** boot0.S.ref	Wed Oct 20 17:24:19 2004
>>  --- boot0.S	Wed Oct 20 17:30:56 2004
>>  ***************
>>  *** 103,112 ****
>>     * Check what flags were loaded with us, specifically, Use a predefined
>>Drive. * If what the bios gives us is bad, use the '0' in the block
>>instead, as well. */
>>  ! 		testb $0x20,_FLAGS(%bp)		# Set number drive?
>>    		jnz main.1			# Yes
>>    		testb %dl,%dl			# Drive number valid?
>>    		js main.2			# Possibly (0x80 set)
>>    main.1:		movb _SETDRV(%bp),%dl		# Drive number to use
>>    /*
>>     * Whatever we decided to use, now store it into the fake
>>  --- 103,117 ----
>>     * Check what flags were loaded with us, specifically, Use a predefined
>>Drive. * If what the bios gives us is bad, use the '0' in the block
>>instead, as well. */
>>  ! 		testb $0x20,_FLAGS(%bp)		# Set drive number?
>>    		jnz main.1			# Yes
>>    		testb %dl,%dl			# Drive number valid?
>>    		js main.2			# Possibly (0x80 set)
>>  + /*
>>  +  * Only update the boot-sector when there is a valid drive number or
>>  +  * the drive number is set manually.
>>  +  */
>>  + 		orb $0x40,_FLAGS(%bp)		# Disable updates
>>    main.1:		movb _SETDRV(%bp),%dl		# Drive number to use
>>    /*
>>     * Whatever we decided to use, now store it into the fake
>>  ***************
>>  *** 203,210 ****
>>    /*
>>     * Start of input loop.  Beep and take note of time
>>     */
>>  ! main.10:	movb $ASCII_BEL,%al		# Signal
>>    		callw putchr			#  beep!
>>    		xorb %ah,%ah			# BIOS: Get
>>    		int $0x1a			#  system time
>>    		movw %dx,%di			# Ticks when
>>  --- 208,218 ----
>>    /*
>>     * Start of input loop.  Beep and take note of time
>>     */
>>  ! main.10:
>>  ! #ifdef BEL
>>  ! 		movb $ASCII_BEL,%al		# Signal
>>    		callw putchr			#  beep!
>>  + #endif
>>    		xorb %ah,%ah			# BIOS: Get
>>    		int $0x1a			#  system time
>>    		movw %dx,%di			# Ticks when
>>
>>  --SUOF0GtieIMvvwua--
>>_______________________________________________
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>>    
>>
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