From: muta...@gmail.com   
      
   Note that the actual problem while running this code   
   (as opposed to "in this code") is that it doesn't hit the   
   bits where it says "doesn't get here".   
      
   And I have determined that the problem is an incorrect   
   relocation - bbdd (bbfd in the executable after the 32   
   bytes of header) is using an offset that goes over the   
   x'e8' call.   
      
   Just by chance, the load point of the executable (x'010700')   
   converted that x'e8' into x'e9', so I believe I got a jmp instead   
   of a call.   
      
   comp5w.bat in sourceforge will reproduce an equivalent   
   broken executable - just that call won't be there at all, so   
   something else gets clobbered.   
      
   BFN. Paul.   
      
      
   C:\devel\pdos\src\xxx2>doit   
      
   C:\devel\pdos\src\xxx2>del pdos.exe   
      
   C:\devel\pdos\src\xxx2>ld86 -Map map.txt -N -s -e start -o pdos.exe strt32.o   
   pdos.o os.a pdos.a   
      
   C:\devel\pdos\src\xxx2>hexdump pdos.exe 0xbbf0 50   
   00BBF0  F10FB682 D1100200 0FB69A00 000D21E8  ..............!.   
   00BC00  F8500000 C1E00809 C30FB682 D2100200  .P..............   
   00BC10  89D1C1E0 108A92D3 10020009 C389D0C1  ................   
   00BC20  E018                                 ..   
      
   C:\devel\pdos\src\xxx2>od386 -x pdos.exe   | grep bbd   
   0000bbd4 32                *ABS*   
   0000bbdd 32                *ABS*   
      
      
      
   _fatNuke:   
   	pushl	%ebp   
   	movl	%esp, %ebp   
   	pushl	%edi   
   	pushl	%esi   
   	pushl	%ebx   
   	subl	$28, %esp   
   	movl	12(%ebp), %ebx   # second parameter is cluster number, now in ebx   
   	testl	%ebx, %ebx   
   	movl	8(%ebp), %edi   # first parameter is FAT *, now in edi   
   	movl	$0, -16(%ebp)   
   	movl	$0, -24(%ebp)   
   	je	L663   
   	.p2align 2   
   L665:   
   	subl	$8, %esp   
   	pushl	%ebx   
   	pushl	%edi   
   	call	_fatEndCluster   
   	addl	$16, %esp   
   	testl	%eax, %eax   
   	jne	L689   
   	movl	92(%edi), %eax   
   	cmpl	$16, %eax   
   	je	L690   
   	cmpl	$12, %eax   
   	je	L691   
   L671:   
   	cmpl	$32, %eax   
   	jne	L665   
           # fatSector = fat->fatstart + (cluster * 4) / fat->sector_size#   
   	xorl	%edx, %edx   
   	leal	0(,%ebx,4), %eax   # cluster number in ebx multiplied by 4   
   	movl	16(%edi), %ecx   # sector_size is at offset 16 in FAT   
   	divl	%ecx    # i think edx contains remainder and is ignored, eax contains   
   extra sectors   
   	movl	%eax, %esi   
   	addl	48(%edi), %esi   # offset 48 is fatstart, now added to extra sectors,   
   result in esi   
   	cmpl	%esi, -16(%ebp)  # stack variable at -16 is "buffered" variable   
           # if (buffered != fatSector)   
   	je	L681        # if we're still doing the same sector number, then jump   
   	movl	-16(%ebp), %eax   
   	testl	%eax, %eax   
   	jne	L692   
   L682:   
   	pushl	%eax   
   	pushl	$_buf.8   
   	pushl	%esi   
   	pushl	%edi   
   	call	_fatReadLogical   
   	movl	%esi, -16(%ebp)   
   	addl	$16, %esp   
   	movl	16(%edi), %ecx   
   L681:   
           # gets here   
   	leal	0(,%ebx,4), %eax  # cluster number in ebx multiplied by 4, and stored in   
   eax   
   	xorl	%edx, %edx   
   	divl	%ecx   # repeat the division, and now using the remainder we have the   
   offset in the sector buffer of interest in edx   
   	movzbl	_buf.8+1(%edx), %eax  # al has one value   
   	movzbl	_buf.8(%edx), %ebx   # bl has one value   
           # gets here   
           call    ___brkpoint   
   	sall	$8, %eax   
           # doesn't get here   
   	orl	%eax, %ebx   # bx has combination of 2 values   
           # doesn't get here   
   	movzbl	_buf.8+2(%edx), %eax   # al has one value   
   	movl	%edx, %ecx   # copy of the offset for later use   
   	sall	$16, %eax  # get al into position   
           # doesn't get here   
   	movb	_buf.8+3(%edx), %dl  # dl has one value - rest of edx hasn't been zeroed   
   	orl	%eax, %ebx  # al above is now in right position of ebx   
   	movl	%edx, %eax  # al has the last (4th) value now (copied from dl)   
   	sall	$24, %eax   # al into right position   
           # doesn't get here   
   	orl	%eax, %ebx  # ebx now complete (cluster number)   
           # & 0x0fffffff#   
   	andl	$-16, %edx  # only want high 4 bits of dl   
           # buf[offset + 3] = buf[offset + 3] & 0xf0#   
   	andl	$268435455, %ebx   # cluster number now masked with 0f ff ff ff   
           # cluster number in ebx is now correct and undisturbed for use as   
   original   
           # now using ecx as offset   
   	movb	$0, _buf.8(%ecx)   
           # doesn't get here   
   	movb	$0, _buf.8+1(%ecx)   
   	movb	$0, _buf.8+2(%ecx)   
   	movb	%dl, _buf.8+3(%ecx)   # those high 4 bits now available for insert   
           # deletedclusters++#   
   	incl	-24(%ebp)   
           # doesn't get here   
   	jmp	L665   
   L692:   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)