first commit

jasmin/jasmin-2.4/examples/Catch.j

@@ -0,0 +1,79 @@
+; --- Copyright Jonathan Meyer 1996. All rights reserved. -----------------
+; File:      jasmin/examples/Catch.j
+; Author:    Jonathan Meyer, 10 July 1996
+; Purpose:   Catching and throwing exceptions
+; -------------------------------------------------------------------------
+
+;
+; This hows how to throw and catch Exceptions in Jasmin
+;
+
+.class public examples/Catch
+.super java/lang/Object
+
+; standard initializer
+.method public <init>()V
+    aload_0
+    invokenonvirtual java/lang/Object.<init>()V
+    return
+.end method
+
+.method public static main([Ljava/lang/String;)V
+
+    .limit locals 3
+    .limit stack 5
+
+    ; set up a handler to catch subclasses of java.lang.Exception
+    .catch java/lang/Exception from Label1 to Label2 using Handler
+
+    ; store System.out in local variable 1
+    getstatic java/lang/System/out Ljava/io/PrintStream;
+    astore_1
+
+    ; print out a message
+    aload_1
+    ldc " -- Before exception"
+    invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
+
+    ; construct an instance of Exception, initialize it with a string,
+    ; throw it. This is like the Java statement :
+    ;
+    ;     throw new Exception("My exception");
+    ;
+
+Label1:
+    new java/lang/Exception
+    dup
+    ldc "<my exception>"
+    invokenonvirtual java/lang/Exception/<init>(Ljava/lang/String;)V
+    athrow
+
+Label2:
+    aload_1
+    ldc " -- After exception"
+    invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
+
+    return
+
+    ; This is the handler for the exception
+
+Handler:
+    ; store the exception in local variable 2
+    astore_2
+
+    ; print out a message
+    aload_1
+    ldc " -- Caught exception: "
+    invokevirtual java/io/PrintStream/print(Ljava/lang/String;)V
+
+    ; call getMessage() to retrieve the message from the Exception...
+    aload_1
+    aload_2
+    invokevirtual java/lang/Throwable/getMessage()Ljava/lang/String;
+    ; ... now print it
+    invokevirtual java/io/PrintStream/println(Ljava/lang/String;)V
+
+    ; return to the code
+    goto Label2
+
+.end method