file copied from ming 0.3alpha2

[swftools.git] / lib / action / assembler.c

diff --git a/lib/action/assembler.c b/lib/action/assembler.c
new file mode 100644 (file)
index 0000000..8526e99
--- /dev/null
+++ b/lib/action/assembler.c
@@ -0,0 +1,131 @@
+/*
+    Ming, an SWF output library
+    Copyright (C) 2002  Opaque Industries - http://www.opaque.net/
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "assembler.h"
+#include "compile.h"
+#include "action.h"
+
+
+int len;
+Buffer asmBuffer;
+int nLabels;
+
+struct label
+{
+       char *name;
+       int offset;
+};
+
+struct label labels[256];
+
+
+static int
+findLabel(char *label)
+{
+       int i;
+
+       for ( i=0; i<nLabels; ++i )
+       {
+               if ( strcmp(label, labels[i].name) == 0 )
+                       return i;
+       }
+
+       return -1;
+}
+
+
+static void
+addLabel(char *label)
+{
+       int i = findLabel(label);
+
+       if ( i == -1 )
+       {
+               labels[nLabels].name = strdup(label);
+               labels[nLabels].offset = len;
+               ++nLabels;
+       }
+       else
+               labels[i].offset = len;
+}
+
+
+int
+bufferBranchTarget(Buffer output, char *label)
+{
+       int i = findLabel(label);
+
+       if ( i == -1 )
+       {
+               i = nLabels;
+               addLabel(label);
+       }
+
+       return bufferWriteS16(output, i);
+}
+
+
+void
+bufferPatchTargets(Buffer buffer)
+{
+       int l, i = 0;
+       unsigned char *output = buffer->buffer;
+
+       while ( i < len )
+       {
+               if ( output[i] & 0x80 ) /* then it's a multibyte instruction */
+               {
+                       if ( output[i] == SWFACTION_BRANCHALWAYS ||
+                                        output[i] == SWFACTION_BRANCHIFTRUE )
+                       {
+                               int target, offset;
+
+                               i += 3; /* plus instruction plus two-byte length */
+
+                               target = output[i];
+                               offset = labels[target].offset - (i+2);
+                               output[i] = offset & 0xff;
+                               output[++i] = (offset>>8) & 0xff;
+                               ++i;
+                       }
+                       else
+                       {
+                               ++i;
+                               l = output[i];
+                               ++i;
+                               l += output[i]<<8;
+
+                               i += l+1;
+                       }
+               }
+               else
+                       ++i;
+       }
+}
+
+
+/*
+ * Local variables:
+ * tab-width: 2
+ * c-basic-offset: 2
+ * End:
+ */