Path: utzoo!attcan!uunet!husc6!mailrus!ames!oliveb!amdahl!amdcad!phil
From: phil@amdcad.AMD.COM (Phil Ngai)
Newsgroups: comp.arch
Subject: Re: More On Write-Only Control Registers
Message-ID: <22150@amdcad.AMD.COM>
Date: 19 Jun 88 03:41:54 GMT
References: <439@cf-cm.UUCP>
Reply-To: phil@amdcad.UUCP (Phil Ngai)
Organization: Advanced Micro Devices
Lines: 16

In article <439@cf-cm.UUCP> mch@computing-maths.cardiff.ac.uk (Major Kano) writes:
>Now that's all very well, but what I was trying to get at was why the **** have 
>write-only control registers or read-only status registers AT ALL ?

Why have write only control registers at all? Cost. Plain and simple.
It costs more to be able to read it. Whether it is worth the cost can
be debated for every application. But that there can be a reason is
not debatable. 

I don't understand what you mean about read only status registers.
Most of the time it doesn't make sense to think about writing them. 

-- 

I speak for myself, not the company.
Phil Ngai, {ucbvax,decwrl,allegra}!amdcad!phil or phil@amd.com