Mail Archives: djgpp/1993/01/10/13:57:45
|<><><><><> Original message from jtevik AT sage DOT nrri DOT umn DOT edu <><><><><>
|>
|> The first time I had to look at a 68000 assembly language book, I was totally
|> lost until I realized that the operand order was reversed from Intel's.
|> Searching through two 68K books, I found no statement of what the operand
|> order should be. It's probably a religious issue, but I would argue that
|> since in most high level languages you would say dest=source, an assembler
|> shouls use the same order.
|>
|Note that assemblers came before high-level languages. It could be argued
|that HLL's should use source=dest :)
The x=y notation came along with FORTRAN. Early documentation of machine
instructions typically looked something like.
a + b --> c
or c <-- a + b
So the real question is what is the correct direction for the arror
to point. The answer of course is that it is rather arbitrary and
some vendors will do it one way and others the other. Personally
I prefer the arrows to point left since it matches common usage.
TJ Merritt
tjm AT Netcom DOT com
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