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From: "Ed G." <edgee@cyberpass.net>
To: Milo Velimirovic <milov@toes.its.uwlax.edu>
Date: Wed, 22 Apr 1998 09:31:05 -0400
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Subject: Re: Floating Point-How Important
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> Unless the program is running on an -11 with separate I and D spaces. In any
> event there is NO guarantee that the data will follow the text of the program. 

Good point.  I hadn't thought of this.

> >Is there such a thing as PC relative mode for the jmp op 
> >code?  In other words, can you make long + or -32K relative jumps on 
> >the PDP-11? If so, this too could potentially confound my estimates.
> 
> Yes. the JMP and JSR instruction both are capable of using the full range of
> addressing (except for register mode) as their destination.

Can you give me some examples as well as your reason for using that 
particular mode?

Would these be a valid instructions?

jmp -10000(pc) ; jump backwards 10000 bytes
jmp 10(r5); jump ten bytes past the location pointed to by r5
jmp @500(pc); jump to the address contained in the location pointed 
to by the sum of 500 and the pc

Ed