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From: don@trsvax.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: Calling C functions from assembly
Message-ID: <216100115@trsvax>
Date: 2 Aug 89 13:41:00 GMT
References: <12324@s.ms.uky.edu>
Lines: 25
Nf-ID: #R:s.ms.uky.edu:12324:trsvax:216100115:000:1150
Nf-From: trsvax.UUCP!don    Aug  2 08:41:00 1989


>>I'm trying to call some C functions from assembly, using MSC 5.0 and either
>>MASM or TASM.  I could write a dummy _main() in C, if this makes things
>>easier, but I'm still not sure what needs to be setup to call a C subroutine.
>>
>>Can anyone clue me in on how to do this?

>[...]
>Note that the parameters are pushed onto the stack in reverse order.  As
>for how to retrieve the functions return value, you'l have to concult
>you compilers documentation.  There is no set convention, however most
			       ^^^^^^^^^^^^^^^^^^^^^^^^^^
>use one of the CPU registers.  If the routine doesn't return a value,
>then all you have to worry about is pushing the parameters onto the
>stack in reverse order, and restoring the stack when the routine is done.

Is this correct?  I thought it was a well-established convention to place
the return value in the AX register.  Are there some commercial compilers
which return it somewhere else?

---------------------------------------------------------------------
Don Subt			The opinions expressed above are
Tandy Corp.			strictly mine, not my employer's.

817-390-3068			...!texbell!letni!rwsys!trsvax!don