From: sandmann AT clio DOT rice DOT edu (Charles Sandmann)
Message-Id: <10109050440.AA12292@clio.rice.edu>
Subject: Re: Win2K breakpoints
To: djgpp-workers AT delorie DOT com
Date: Tue, 4 Sep 2001 23:40:12 -0500 (CDT)
In-Reply-To: <10109050334.AA20161@clio.rice.edu> from "Charles Sandmann" at Sep 04, 2001 10:34:16 PM
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Enclosed is WIP diff on dbgcom.c.  This is diffed from last week's dbgcom.c,
not latest cvs updates with Eli's volatile fixes.  It contains debug printf
statements.  I removed the assembly block and replaced it with our libc
dpmi call to allocate a breakpoint (the dbgcom.c code pre-dates the dpmi
calls being written in standard form :-)

I've added the Win2K workaround code, and edebug seems to work on Win2K.
Theoretically if I rebuilt the other debuggers they would behave better
also, but no time.

For your comments and amusement, since I may not get back to it this week.

*** dbgcom.c_	Fri Jul 13 12:50:10 2001
--- dbgcom3.c	Tue Sep  4 23:32:02 2001
*************** void load_npx (void)
*** 206,236 ****
    asm ("frstor %0" : "=m" (npx));
  }
  
- static int _DPMIsetBreak(unsigned short sizetype, unsigned vaddr)
- {
- 	int handle;
- 
- 	asm volatile(						       "\n\
- 	    movw   %1,%%dx						\n\
- 	    movl   %2,%%ecx						\n\
- 	    movl   %%ecx,%%ebx						\n\
- 	    shrl   $16,%%ebx						\n\
- 	    movw   $0x0b00,%%ax						\n\
- 	    int    $0x31						\n\
- 	    jnc    3f							\n\
- 	    xorl   %%ebx,%%ebx						\n\
- 	    decl   %%ebx						\n\
- 	    jmp    1f							\n\
- 3:          movzwl %%bx,%%ebx						\n\
- 1:	    movl   %%ebx,%0						\n\
- 	    "
- 	    : "=g" (handle)			/* outputs */
- 	    : "g" (sizetype), "g"  (vaddr)	/* inputs */
- 	    : "ax", "bx", "cx", "dx"		/* regs used */
- 	);
- 	return handle;
- }
- 
  static int _DPMIcancelBreak(int handle)
  {
  	unsigned state;
--- 206,211 ----
*************** static int _DPMIcancelBreak(int handle)
*** 251,256 ****
--- 226,232 ----
  	    : "g"  (handle)			/* inputs */
  	    : "ax", "bx"			/* regs used */
  	);
+ 	printf("CancelBreak han=%d returns state=%d\n",handle,state);
  	return state;
  }
  
*************** static int _DPMIcancelBreak(int handle)
*** 258,267 ****
  void _set_break_DPMI(void);
  void _set_break_DPMI(void)
  {
!   int i;
    unsigned extract;
!   unsigned short sizetype;
    unsigned long vbase;
    
    if(__dpmi_get_segment_base_address(app_ds, &vbase) == -1)
      return;
--- 234,244 ----
  void _set_break_DPMI(void);
  void _set_break_DPMI(void)
  {
!   int i,rv;
    unsigned extract;
!   unsigned char brtype;
    unsigned long vbase;
+   __dpmi_meminfo bpinfo;
    
    if(__dpmi_get_segment_base_address(app_ds, &vbase) == -1)
      return;
*************** void _set_break_DPMI(void)
*** 271,284 ****
  
    for(i=0;i<4;i++)
      if( (edi.dr[7] >> (i*2))&3 ) {		/* enabled? */
!       sizetype = (extract >> (i*4)) & 3;    /* extract the type */
!       if(sizetype == 3) sizetype = 2;       /* convert for DPMI brain damage */
!       sizetype = (sizetype << 8) + ((extract >> (i*4+2)) & 3) + 1; /* & size */
!       breakhandle[i] = _DPMIsetBreak(sizetype, edi.dr[i]+vbase);
!       if(breakhandle[i] == -1)
!         printf("Error allocating DPMI breakpoint at address 0x%08lx\n",edi.dr[i]);
!       else
          nset++;
      } else
        breakhandle[i] = -1;
    return;
--- 248,271 ----
  
    for(i=0;i<4;i++)
      if( (edi.dr[7] >> (i*2))&3 ) {		/* enabled? */
!       brtype = (extract >> (i*4)) & 3;    /* extract the type */
!       if(brtype == 3) brtype = 2;       /* convert for DPMI brain damage */
! 
!       bpinfo.handle = -1;
!       bpinfo.size = ((extract >> (i*4+2)) & 3) + 1; /* size */
!       bpinfo.address = edi.dr[i]+vbase;
!       printf("SetBreak typ=%d siz=%d at 0x%x ",brtype,(int)bpinfo.size,(unsigned)bpinfo.address);
!       rv = __dpmi_set_debug_watchpoint(&bpinfo, brtype );
!       if(rv != -1) {
!         breakhandle[i] = bpinfo.handle;
!         if(breakhandle[i] == (bpinfo.address >> 16) ) /* Win 2K bug */
!           breakhandle[i] = nset;
          nset++;
+         printf("returns han=%d\n",breakhandle[i]);
+       } else {
+         printf("Error allocating DPMI breakpoint at address 0x%08lx\n",edi.dr[i]);
+         breakhandle[i] = -1;
+       }
      } else
        breakhandle[i] = -1;
    return;