diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 49378ae057d..8bd5348c97c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2010-11-08  Paul Koning  <ni1d@arrl.net>
+
+	* config/pdp11/pdp11.c (pdp11_assemble_integer): Mask byte values
+	to 8 bits.
+
 2010-11-08  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	PR target/46378
diff --git a/gcc/config/pdp11/pdp11.c b/gcc/config/pdp11/pdp11.c
index 31e85c7e6f8..a9c758b4548 100644
--- a/gcc/config/pdp11/pdp11.c
+++ b/gcc/config/pdp11/pdp11.c
@@ -1002,7 +1002,10 @@ pdp11_assemble_integer (rtx x, unsigned int size, int aligned_p)
       {
       case 1:
 	fprintf (asm_out_file, "\t.byte\t");
-	output_addr_const_pdp11 (asm_out_file, x);
+	output_addr_const_pdp11 (asm_out_file, 
+				 GEN_INT (trunc_int_for_mode (INTVAL (x),
+							      QImode) & 0xff));
+;
 	fprintf (asm_out_file, " /* char */\n");
 	return true;
 
@@ -1739,9 +1742,7 @@ output_addr_const_pdp11 (FILE *file, rtx x)
       break;
 
     case CONST_INT:
-      /* Should we check for constants which are too big?  Maybe cutting
-	 them off to 16 bits is OK?  */
-      fprintf (file, "%#ho", (unsigned short) INTVAL (x));
+      fprintf (file, "%#o", (int) trunc_int_for_mode (INTVAL (x), HImode) & 0xffff);
       break;
 
     case CONST: