diff --git a/module/language/c99/compiler.mes b/module/language/c99/compiler.mes
index 51d24870..719ec5e7 100644
--- a/module/language/c99/compiler.mes
+++ b/module/language/c99/compiler.mes
@@ -761,15 +761,27 @@
                           (list (lambda (f g ta t d)
                                   (i386:accu-base)))))))        
 
-        ((lshift ,a (p-expr (fixed ,value)))
+        ((bitwise-or ,a ,b)
          (let* ((empty (clone info #:text '()))
                 (accu ((expr->accu empty) a))
-                (value (cstring->number value)))
+                (base ((expr->base empty) b)))
            (clone info #:text
                   (append text
                           (.text accu)
+                          (.text base)
                           (list (lambda (f g ta t d)
-                                  (i386:accu-shl value)))))))
+                                  (i386:accu-or-base)))))))
+
+        ((lshift ,a ,b)
+         (let* ((empty (clone info #:text '()))
+                (accu ((expr->accu empty) a))
+                (base ((expr->base empty) b)))
+           (clone info #:text
+                  (append text
+                          (.text accu)
+                          (.text base)
+                          (list (lambda (f g ta t d)
+                                  (i386:accu<<base)))))))
 
         ((div ,a ,b)
          (let* ((empty (clone info #:text '()))
diff --git a/module/mes/as-i386.mes b/module/mes/as-i386.mes
index 287066cd..a2762740 100644
--- a/module/mes/as-i386.mes
+++ b/module/mes/as-i386.mes
@@ -126,6 +126,11 @@
   (or n accu:shl n)
   `(#xc1 #xe0 ,n))                      ; shl    $0x8,%eax
 
+(define (i386:accu<<base)
+  '(#x31 #xc9                           ; xor    %ecx,%ecx
+    #x89 #xd1                           ; mov    %edx,%ecx
+    #xd3 #xe0))                         ; shl    %cl,%eax
+
 (define (i386:accu+accu)
   '(#x01 #xc0))                         ; add    %eax,%eax
 
diff --git a/module/mes/as-i386.scm b/module/mes/as-i386.scm
index 9c5fd439..fa543c54 100644
--- a/module/mes/as-i386.scm
+++ b/module/mes/as-i386.scm
@@ -46,6 +46,7 @@
             i386:accu*base
             i386:accu-base
             i386:accu-shl
+            i386:accu<<base
             i386:base-sub
             i386:base->accu
             i386:base->accu-address
diff --git a/scaffold/t.c b/scaffold/t.c
index cffa2ce7..419e7533 100644
--- a/scaffold/t.c
+++ b/scaffold/t.c
@@ -212,6 +212,13 @@ math_test ()
   puts ("t: 3*4=");
   i = 3 * 4;
   if (i!=12) return 1;
+
+  puts ("t: 1 << 3\n");
+  if (1 << 3 != 8) return 1 << 3;
+
+  puts ("t: 3 << 4\n");
+  if (3 << 4 != 48) return 3 << 4;
+
   return read_test ();
 }