debugx: save/restore exc 0d/0e on entry/exit debugger

Author: Baron-von-Riedesel

DEBUG.TXT

@@ -794,10 +794,15 @@
  Sometimes Q may not work to exit protected-mode, then one can try
  to forcably terminate the debuggee with the command variant QQ.
 
- If a second video adapter is available, DEBUGX may be told to display
+  If a second video adapter is available, DEBUGX may be told to display
  its output to that device via the /2 cmdline option. This gives DEBUGX
  the ability to debug graphics applications.
 
+  The HX PE loader DPMILD32 may set pages of code sections to readonly
+ if certain conditions are met. This reliably prevents DEBUGX from setting
+ its breakpoints. There should exist an option to make DPMILD32 not modify
+ those page attributes - see the docs supplied with DPMILD32 for details.
+
 
  9. Installing and Initializing DebugB
  -------------------------------------

HISTORY.TXT

@@ -261,7 +261,7 @@
          intercepted protected-mode int 21h and refuses to quit.
        - another variant - DEBUGXV - may be created. It allows to flip video
          screen between debugger and debuggee.
-    2.00 [30 November 2022]
+    2.00 [3 December 2022]
        - ensure the correct video page is used when debugger has to display
          something if the InDOS flag is set AND page swapping is active.
        - DEBUGX: hook into protected-mode debug interface Int 41h and make
@@ -292,3 +292,4 @@
          converted to selectors during initial switch to protected-mode.
        - DEBUGX fix, m cmd: '$' qualifier for the source address segment was
          rejected.
+       - DEBUGX: exceptions 0dh/0eh are set/reset on debugger entry/exit.