diff --git a/compiler/x86/aasmcpu.pas b/compiler/x86/aasmcpu.pas
index 8ae58bda0a..0a685601c3 100644
--- a/compiler/x86/aasmcpu.pas
+++ b/compiler/x86/aasmcpu.pas
@@ -1664,8 +1664,9 @@ implementation
                   else
                   begin
                     { allow 2nd, 3rd or 4th operand being a constant and expect no size for shuf* etc. }
-                    { further, allow AAD and AAM with imm. operand }
+                    { further, allow ENTER, AAD and AAM with imm. operand }
                     if (opsize=S_NO) and not((i in [1,2,3])
+                      or ((i=0) and (opcode in [A_ENTER]))
 {$ifndef x86_64}
                       or ((i=0) and (opcode in [A_AAD,A_AAM]))
 {$endif x86_64}
diff --git a/tests/test/tasm30.pp b/tests/test/tasm30.pp
new file mode 100644
index 0000000000..c3e1a7c3a7
--- /dev/null
+++ b/tests/test/tasm30.pp
@@ -0,0 +1,10 @@
+{ %NORUN }
+{ %CPU=i386,x86_64 }
+
+program tasm30;
+
+begin
+  asm
+    enter $5,$1234
+  end;
+end.