Fix decoding of line numbers.

[bascat] / bascat.c

diff --git a/bascat.c b/bascat.c
index b685a5c..48e032e 100644 (file)
--- a/bascat.c
+++ b/bascat.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
- * $Id: bascat.c,v 1.4 1999/10/28 10:42:23 mdw Exp $
+ * $Id: bascat.c,v 1.5 1999/11/25 01:08:57 mdw Exp $
  *
  * Display BBC BASIC programs more or less anywhere
  *
@@ -29,6 +29,9 @@
 /*----- Revision history --------------------------------------------------*
  *
  * $Log: bascat.c,v $
+ * Revision 1.5  1999/11/25 01:08:57  mdw
+ * Fix decoding of line numbers.
+ *
  * Revision 1.4  1999/10/28 10:42:23  mdw
  * More minor twiddling.
  *
@@ -226,7 +229,7 @@ static void keyword(const char *s, FILE *fp)
  * Use:         Decodes multibyte tokens.
  */
 
-static int mbtok(int byte, const char *t[], int n, FILE * fp)
+static int mbtok(int byte, const char *t[], int n, FILE *fp)
 {
   byte -= 0x8E;
   if (byte >= n)
@@ -246,7 +249,7 @@ static int mbtok(int byte, const char *t[], int n, FILE * fp)
  * Use:         Decodes a byte, changing states as necessary.
  */
 
-static int decode(int byte, FILE * fp)
+static int decode(int byte, FILE *fp)
 {
   switch (state) {
 
@@ -324,17 +327,20 @@ static int decode(int byte, FILE * fp)
     /* --- Encoded line number states --- */
 
     case s_linex:
-      lineno = ((((byte << 2) | (byte << 12)) & 0xc0c0u) ^ 0x4040u);
+      byte ^= 0x54;
+      lineno = (((byte & 0x30) << 2) |
+               ((byte & 0x0c) << 12) |
+               ((byte & 0x03)  << 16));
       state++;
       break;
 
     case s_liney:
-      lineno |= byte & 0x3fu;
+      lineno |= byte & 0x3f;
       state++;
       break;
 
     case s_linez:
-      lineno |= (byte << 8) & 0x3fu;
+      lineno |= (byte & 0x3f) << 8;
       fprintf(fp, "%u", lineno);
       state = s_normal;
       break;
@@ -386,7 +392,7 @@ static int line(FILE *in, FILE *out)
       goto eof;
     len -= 4;
 
-    state = s_normal;
+    state = s_keyword;
     while (len) {
       byte = getc(in);
       D( fprintf(stderr, "state == %i, byte == %i\n",