[fuse-emulator-cvs] SF.net SVN: fuse-emulator:[5162] trunk/libspectrum

[<zu...@us...>]

Revision: 5162
          http://sourceforge.net/p/fuse-emulator/code/5162
Author:   zubzero
Date:     2015-03-16 23:44:35 +0000 (Mon, 16 Mar 2015)
Log Message:
-----------
Store PC-1 for all snapshot formats whilst in the halted state

Modified Paths:
--------------
    trunk/libspectrum/hacking/ChangeLog
    trunk/libspectrum/snapshot.c

Modified: trunk/libspectrum/hacking/ChangeLog
===================================================================
--- trunk/libspectrum/hacking/ChangeLog	2015-03-16 23:42:32 UTC (rev 5161)
+++ trunk/libspectrum/hacking/ChangeLog	2015-03-16 23:44:35 UTC (rev 5162)
@@ -1000,3 +1000,5 @@
 20150316 generate.pl.in,libspectrum.h.in: remove autogeneration warning from
          libspectrum.h.in (Stuart).
 20150316 doc/libspectrum.txt: add missing line break (Stuart).
+20150316 snapshot.c: store PC-1 for all snapshot formats whilst in the halted
+         state (Stuart).

Modified: trunk/libspectrum/snapshot.c
===================================================================
--- trunk/libspectrum/snapshot.c	2015-03-16 23:42:32 UTC (rev 5161)
+++ trunk/libspectrum/snapshot.c	2015-03-16 23:44:35 UTC (rev 5162)
@@ -361,6 +361,13 @@
     return LIBSPECTRUM_ERROR_LOGIC;
   }
 
+  /* Sadly, virtually all emulators handle saving of PC incorrectly when
+   * executing a HALT instruction, so it's easiest to deal with this just
+   * once, so that it affects all snapshot formats. */
+  if( libspectrum_snap_halted( snap ) ) {
+    libspectrum_snap_set_pc( snap, libspectrum_snap_pc( snap ) + 1 );
+  }
+
   libspectrum_free( new_buffer );
   return error;
 }
@@ -373,6 +380,7 @@
 {
   libspectrum_class_t class;
   libspectrum_error error;
+  libspectrum_word orig_pc;
 
   error = libspectrum_identify_class( &class, type );
   if( error ) return error;
@@ -383,17 +391,29 @@
     return LIBSPECTRUM_ERROR_INVALID;
   }
 
+  /* Sadly, virtually all emulators handle saving of PC incorrectly when
+   * executing a HALT instruction, so it's easiest to deal with this just
+   * once, so that it affects all snapshot formats. */
+  orig_pc = libspectrum_snap_pc( snap );
+  if( libspectrum_snap_halted( snap ) ) {
+    libspectrum_snap_set_pc( snap, orig_pc - 1 );
+  }
+
   switch( type ) {
 
   case LIBSPECTRUM_ID_SNAPSHOT_SNA:
-    return libspectrum_sna_write( buffer, length, out_flags, snap, in_flags );
+    error = libspectrum_sna_write( buffer, length, out_flags, snap, in_flags );
+    break;
 
   case LIBSPECTRUM_ID_SNAPSHOT_SZX:
-    return libspectrum_szx_write( buffer, length, out_flags, snap, creator,
-				  in_flags );
+    error = libspectrum_szx_write( buffer, length, out_flags, snap, creator,
+				   in_flags );
+    break;
 
   case LIBSPECTRUM_ID_SNAPSHOT_Z80:
-    return libspectrum_z80_write2( buffer, length, out_flags, snap, in_flags );
+    error = libspectrum_z80_write2( buffer, length, out_flags, snap,
+				    in_flags );
+    break;
 
   default:
     libspectrum_print_error( LIBSPECTRUM_ERROR_UNKNOWN,
@@ -401,6 +421,11 @@
     return LIBSPECTRUM_ERROR_UNKNOWN;
 
   }
+
+  /* Put back the correct value of PC, in case snap is needed again */
+  libspectrum_snap_set_pc( snap, orig_pc );
+
+  return error;
 }
 
 /* Given a 48K memory dump `data', place it into the

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