diff --git a/assemble.c b/assemble.c
index fd56f5b8..38add4f6 100644
--- a/assemble.c
+++ b/assemble.c
@@ -160,7 +160,7 @@
  * \340             resb                        reserve <operand 0> bytes of uninitialized storage.
  *                                              Operand 0 had better be a segmentless constant.
  * \341             wait                        this instruction needs a WAIT "prefix"
- * \360                                         no SSE prefix (== \364\331)
+ * \360             np                          no SSE prefix (== \364\331)
  * \361                                         66 SSE prefix (== \366\331)
  * \364             !osp                        operand-size prefix (0x66) not permitted
  * \365             !asp                        address-size prefix (0x67) not permitted
diff --git a/insns.pl b/insns.pl
index 451c4f2b..25049816 100755
--- a/insns.pl
+++ b/insns.pl
@@ -772,6 +772,7 @@ sub byte_code_compile($$) {
         'norep'     => 0331,    # No REP prefix permitted
         'wait'      => 0341,    # Needs a wait prefix
         'resb'      => 0340,
+        'np'        => 0360,    # No prefix
         'jcc8'      => 0370,    # Match only if Jcc possible with single byte
         'jmp8'      => 0371,    # Match only if JMP possible with single byte
         'jlen'      => 0373,    # Length of jump
@@ -825,16 +826,14 @@ sub byte_code_compile($$) {
         if (defined $pc) {
             # Plain code
             push(@codes, $pc);
-        } elsif ($prefix_ok && $op =~ /^(66|f2|f3|np)$/) {
-            # 66/F2/F3 prefix used as an opcode extension, or np = no prefix
+        } elsif ($prefix_ok && $op =~ /^(66|f2|f3)$/) {
+            # 66/F2/F3 prefix used as an opcode extension
             if ($op eq '66') {
                 push(@codes, 0361);
             } elsif ($op eq 'f2') {
                 push(@codes, 0332);
-            } elsif ($op eq 'f3') {
-                push(@codes, 0333);
             } else {
-                push(@codes, 0360);
+                push(@codes, 0333);
             }
         } elsif ($op =~ /^[0-9a-f]{2}$/) {
             if (defined($litix) && $litix+$codes[$litix]+1 == scalar @codes &&