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From: reg@lti.com (Rick Genter x18)
Newsgroups: comp.lang.c
Subject: Re:  info-c digest v2n226
Message-ID: <8810242200.AA05011@lti.com>
Date: 24 Oct 88 22:00:07 GMT
Article-I.D.: lti.8810242200.AA05011
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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> Can someone explain to me what the difference is between a hardware stack
> and a software stack? 

The difference is that a machine with a hardware stack can dereference
the top of the stack and modify the stack pointer as an atomic operation
(usually via an addressing mode).  A machine with "only" software stacks
must use multiple machine instructions to perform this operation; this
makes things hairy in the world of interrupt processing.  Not impossible;
just hairy.  An example is the IBM/370 architecture: there one uses
static saveareas for handling interruptions/exceptions.  Yuck.

					- reg
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