Re: Denial of denial of service

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From: Sean Conner
Subject: Re: Denial of denial of service
Date: 21:20 on 29 Jan 2007
It was thus said that the Great David Cantrell once stated:
> On Mon, Jan 29, 2007 at 02:54:21PM -0500, Sean Conner wrote:
> 
> >   VMS.  Or rather, VMS on the VAX architecture
> 
> Ahh, the pinnacle of CISC.  I have learnt to never be surprised at Weird
> Shit in the VAX instruction set.  I expect to find a single-instruction
> printf() in there at some point.

  No, don't see a printf(), but there is a CRC instruction, and the CASE
instruction could, in theory, fill all available memory.

  Oddly enough, it's missing an AND and OR instruction.  Hateful, that.

  But dispite that, the instruction set *is* very orthogonal.  All the
registers are general purpose (although R15 also doubles as PC) and as far
as I can see, there are no restrictions on addressing modes for any
instruction---so while the assembler *might* restrict something like:

	ADDL2	#45,#66

It *is* possible to do that (talk about self-modifying code) since that
instruction is actually encoded as:

	ADDL2	(R15)+,(R15)+

which is also:

	ADDL2	(PC)+,(PC)+

  -spc (And VMS at the command line is *very* hateful, except for the help
	facility, which makes Unix's man hateful)

There's stuff above here

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