[fuse-emulator-cvs] SF.net SVN: fuse-emulator:[5724] trunk/libspectrum

[<fr...@us...>]

Revision: 5724
          http://sourceforge.net/p/fuse-emulator/code/5724
Author:   fredm
Date:     2016-08-10 12:03:21 +0000 (Wed, 10 Aug 2016)
Log Message:
-----------
TZX spec says that 0 duration pauses should have no effect on the current level.

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

Modified: trunk/libspectrum/hacking/ChangeLog
===================================================================
--- trunk/libspectrum/hacking/ChangeLog	2016-08-07 22:07:22 UTC (rev 5723)
+++ trunk/libspectrum/hacking/ChangeLog	2016-08-10 12:03:21 UTC (rev 5724)
@@ -1100,3 +1100,5 @@
 20160801 zip.c: activate the const-enabled zlib API (Sergio).
 20160802 zip.c: avoid mixing declarations and code for C89 compilers (Sergio).
 20160802 zip.c: minor tweaks to make things a bit more idiomatic (Fred).
+20160810 tape.c: TZX spec says that 0 duration pauses should have no effect on
+         the current level (Fred).

Modified: trunk/libspectrum/tape.c
===================================================================
--- trunk/libspectrum/tape.c	2016-08-07 22:07:22 UTC (rev 5723)
+++ trunk/libspectrum/tape.c	2016-08-10 12:03:21 UTC (rev 5724)
@@ -528,6 +528,21 @@
                                                   &(tape->state) );
 }
 
+/* TZX pauses should have no edge if there is no duration, from the spec:
+   A 'Pause' block of zero duration is completely ignored, so the 'current pulse
+   level' will NOT change in this case. This also applies to 'Data' blocks that
+   have some pause duration included in them. */
+static void
+do_tail_pause( libspectrum_dword *tstates,
+               int *end_of_block, int *flags )
+{
+  *end_of_block = 1;
+  if( *tstates == 0 ) {
+    /* The tail pause is optional - if there is no tail, there is no edge */
+    *flags |= LIBSPECTRUM_TAPE_FLAGS_NO_EDGE;
+  }
+}
+
 static libspectrum_error
 rom_edge( libspectrum_tape_rom_block *block,
           libspectrum_tape_rom_block_state *state,
@@ -579,7 +594,7 @@
   case LIBSPECTRUM_TAPE_STATE_PAUSE:
     /* The pause at the end of the block */
     *tstates = block->pause_tstates;
-    *end_of_block = 1;
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:
@@ -676,7 +691,7 @@
   case LIBSPECTRUM_TAPE_STATE_PAUSE:
     /* The pause at the end of the block */
     *tstates = block->pause_tstates;
-    *end_of_block = 1;
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:
@@ -784,7 +799,7 @@
   case LIBSPECTRUM_TAPE_STATE_PAUSE:
     /* The pause at the end of the block */
     *tstates = block->pause_tstates;
-    *end_of_block = 1;
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:
@@ -857,7 +872,7 @@
   case LIBSPECTRUM_TAPE_STATE_PAUSE:
     /* The pause at the end of the block */
     *tstates = block->pause_tstates;
-    *end_of_block = 1;
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:
@@ -1017,7 +1032,7 @@
   case LIBSPECTRUM_TAPE_STATE_PAUSE:
     /* The pause at the end of the block */
     *tstates = block->pause_tstates;
-    *end_of_block = 1;
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:
@@ -1185,11 +1200,7 @@
   case LIBSPECTRUM_TAPE_STATE_TAIL:
     /* The pulse at the end of the block */
     *tstates = block->tail_length;
-    *end_of_block = 1;
-    if( *tstates == 0 ) {
-      /* The tail pulse is optional - if there is no tail, there is no edge */
-      *flags |= LIBSPECTRUM_TAPE_FLAGS_NO_EDGE;
-    }
+    do_tail_pause( tstates, end_of_block, flags );
     break;
 
   default:

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