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From: srm@iris.berkeley.edu (Richard Mateosian)
Newsgroups: net.arch
Subject: Re: Where are delayed branches handled?
Message-ID: <1147@jade.BERKELEY.EDU>
Date: Fri, 22-Aug-86 06:48:45 EDT
Article-I.D.: jade.1147
Posted: Fri Aug 22 06:48:45 1986
Date-Received: Sat, 23-Aug-86 10:26:50 EDT
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Reply-To: srm@iris.berkeley.edu.UUCP (Richard Mateosian)
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>I believe the SOAP (Symbolic Optimizing Assembly Program) did instruction
>scheduling.

Actually not exactly.  It never reordered instructions.  On the IBM 650, 
the main memory was a 2000-word drum, and each instruction had the format

           op  addr   addr

The first addr was the drum address of the operand, and the second was the
drum address of the next instruction. (You thought linked lists were
invented by software people?)

SOAP let you omit specifying the second addr.  Then by taking account of
how far the drum would turn during execution of op, it found an optimal
drum placement for the next instruction.


Richard Mateosian    ...ucbvax!ucbiris!srm 	     2919 Forest Avenue     
415/540-7745         srm%ucbiris@Berkeley.EDU        Berkeley, CA  94705