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From: hoffman@hdsvx1.UUCP
Newsgroups: net.arch
Subject: Re: Using C as an aid to hand writing assembler
Message-ID: <155@hdsvx1.UUCP>
Date: Sat, 24-May-86 08:30:06 EDT
Article-I.D.: hdsvx1.155
Posted: Sat May 24 08:30:06 1986
Date-Received: Mon, 26-May-86 01:48:55 EDT
References: <817@harvard.UUCP> <491@rna.UUCP> <2763@utcsri.UUCP>
Reply-To: hoffman@hdsvx1.UUCP (Richard hoffman)
Organization: Schlumberger HDS, Houston
Lines: 25

>>> 	Some years ago when I was learning 6800 assembler (anybody remember
>>> D2 kits?) I used to first write everything in C and then hand compile it
>>> into M6800 asm. ...


I used this technique in the late 70's at Texas Instruments, when I was given
a summer to code some mathematical utilities against some *very* tight size
and timing considerations.  I first wrote the code in FORTRAN (it was all we
had, plus it wasn't so bad for short math programs like that), debugged it
completely, then compiled it with the list option, and hand-optimized loops
and register usage.  It worked like gang-busters, and probably increased my
productivity by 200% since it only took me a month to do the whole set when
they had expected it to take three months-- especially since it was my first
contact with assembly language!

I used this technique again several years later to do some programming on a
Motorola 68000 -- not only is it fast, but it's a great way to learn a new
assembly language, and it provides an extra layer of testing and documentation.
I never have understood why everyone doesn't use it.  Even if your compiler
is a real dog, you can fix bad code that you understand a lot easier than you
can write good code from scratch.

Richard Hoffman
Schlumberger Well Services
hoffman%hdsvx1@slb-doll.csnet