[comp.os.vms] merging assembly with high-level languauges

tada@athena.mit.edu (Michael Zehr) (05/19/88)

I need some simple examples on how to combine assembly code with high
level language source.  For example, suppose i want to write some C
code, but tweak the machine code it produces.  I have a vague idea on
how to proceed (compile the C source with the /machine option, then
edit the listing to make the changes, then assemble the machine code,
then link everything) but i need some examples to get me started.

anyone out there have experience with this?

thanks in advance.

-michael j zehr

WHEELER@CC.UTAH.EDU (05/19/88)

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Subject: merging assembly with high-level languauges               
 
Trying to assemble the listing that comes from cc/list/mach will not work.
The only compiler that can produce machine language listing that can be
assembled without problems is Bliss. (A truely wonderful language!)

What you want to do is write you machine language routines and then call
them from C. You can get a good feel for what to write by looking at the
code generated from the compilers. I learned PDP assembly by looking at
the output from a FORTRAN compiler.

Bob Wheeler
Howard Hughes Medical Institute at Salt Lake City
bob%howard@cc.utah.edu

EPRF@SNYCENVM.BITNET (Peter Flass) (05/24/88)

>
>I need some simple examples on how to combine assembly code with high
>level language source.  For example, suppose i want to write some C
>code, but tweak the machine code it produces.  I have a vague idea on
>how to proceed (compile the C source with the /machine option, then
>edit the listing to make the changes, then assemble the machine code,
>then link everything) but i need some examples to get me started.
>
 Last time I did anything like this I swore off for life!  For what
my two cents is worth you'd be *MUCH* better off leaving the compiled
code alone and putting your 'tweaked' code into a handcoded Macro function
(using the compiler output as a model if needed).
  Otherwise every time you make a source change you have to remember
to make your Macro changes again and you're at the mercy of the compiler
as to whether they'll fit.
   - Pete