Gopal,

I don't know the answer to your question as I never used PCA, but next time would you please use the forward slash (/) rather than backslash (\) within the </pre> tag to close the quoted code... And preview your post prior storing... Doing it the other way completely blew the margins on this post.

Thanks

JW

PS. Perhaps you could give us here an example of the "wrong output"
PS2. Isn't this interrupt code a little bit lengthy? How does the asm output look like?