* m68hc11-dis.c (print_insn): Fix disassembly of movb with a

[deliverable/binutils-gdb.git] / opcodes / m68hc11-dis.c

diff --git a/opcodes/m68hc11-dis.c b/opcodes/m68hc11-dis.c
index 31fbf27eaae6c739ac027a519e26c2212ce7b65e..bb0cc207d4d3cddac65d95d12ca70faaca0fdaae 100644 (file)
--- a/opcodes/m68hc11-dis.c
+++ b/opcodes/m68hc11-dis.c
@@ -366,14 +366,35 @@ print_insn (memaddr, info, arch)
          (*info->fprintf_func) (info->stream, "\t");
        }
 
-      /* The movb and movw must be handled in a special way...  */
-      offset = 0;
-      if (format & (M6812_OP_IDX_P2 | M6812_OP_IND16_P2))
-       {
-         if ((format & M6812_OP_IDX_P2)
-             && (format & (M6811_OP_IMM8 | M6811_OP_IMM16 | M6811_OP_IND16)))
-           offset = 1;
-       }
+      /* The movb and movw must be handled in a special way...
+         The source constant 'ii' is not always at the same place.
+         This is the same for the destination for the post-indexed byte.
+         The 'offset' is used to do the appropriate correction.
+
+                                   offset          offset
+                              for constant     for destination
+         movb   18 OB ii hh ll       0          0
+                18 08 xb ii          1          -1
+                18 0C hh ll hh ll    0          0
+                18 09 xb hh ll       1          -1
+                18 0D xb hh ll       0          0
+                18 0A xb xb          0          0
+
+         movw   18 03 jj kk hh ll    0          0
+                18 00 xb jj kk       1          -1
+                18 04 hh ll hh ll    0          0
+                18 01 xb hh ll       1          -1
+                18 05 xb hh ll       0          0
+                18 02 xb xb          0          0
+
+         After the source operand is read, the position 'pos' is incremented
+         this explains the negative offset for destination.
+
+         movb/movw above are the only instructions with this matching
+         format.  */
+      offset = ((format & M6812_OP_IDX_P2)
+                && (format & (M6811_OP_IMM8 | M6811_OP_IMM16 |
+                              M6811_OP_IND16)));
 
       /* Operand with one more byte: - immediate, offset,
          direct-low address.  */
@@ -387,7 +408,10 @@ print_insn (memaddr, info, arch)
            }
 
          pos++;
-         offset = -1;
+
+          /* This movb/movw is special (see above).  */
+          offset = -offset;
+
          if (format & M6811_OP_IMM8)
            {
              (*info->fprintf_func) (info->stream, "#%d", (int) buffer[0]);