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From: news@ucf1vm.BITNET
Newsgroups: comp.lang.asm370
Subject: Re: MVCL (was Re: why code in 370 Assembler)
Message-ID: <9104290458.AA06736@ucbvax.Berkeley.EDU>
Date: 29 Apr 91 04:10:26 GMT
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Reply-To: IBM 370 Assembly Programming Discussion List
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rickert@CS.NIU.EDU (Neil Rickert) writes:

> But of course your 18 bytes is a serious underestimate.  After all you must
>first save the current contents of the registers, and later restore them.
>If something is really worth doing in assembler, you are probably going to
>have all registers tied up, so there just aren't two even/odd pairs readily
>available.  MVCL is mostly useful when you need its feature of padding the
>destination.

In most cases, when I need an MVCL, the addresses I need are already in
the registers.  Careful register reallocation gets them into the correct
registers.  For instance I try to keep address/length data in even/odd
pairs even before I anticipate needing an MVCL.  Only rarely do I need
to dump something out of registers to do an MVCL.
--
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/ Phil Howard -- KA9WGN -- phil@ux1.cso.uiuc.edu   |  Guns don't aim guns at  \
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