cy@killer.DALLAS.TX.US (Cyrus Foughty) (10/22/88)
I have a assembly language program from which I want to
call a "C" function. I know this is backwards from what
everyone else does. BTW, I am using Microsoft Masm and
"C" 5.1 for this little dodad. THE Microsoft manuals tell
how to interface an assembly language routine but not the
other way round. I would be forced to change ALL my assembly
programs to match what "C" wants and that is not an option.
I have way to much assembly to change. How do I do it?
--
cy
{ames,decwrl}!killer!cy
MaBell: 408.255.5990
IRS Motto: Reach out and touch someone! everett@hpcvlx.HP.COM (Everett Kaser) (10/25/88)
This is a case of RTFM, I'd say. Both my 5.01 MASM and my 5.x C have a manual, or section of a manual (they're both the exact same pages, just one is a stand-alone manual, and the other is a section of a binder) called "Mixed Language Programming Guide". Section 6.6 of that guide is titled "Calling High-Level Languages from Assembly". The first paragraph is: High-level language routines assume that certain initialization code has previously been executed; you can ensure that the proper initialization is performed by starting in a high-level language module, and then calling an assembly procedure. THE ASSEMBLY PROCEDURE CAN THEN CALL HIGH-LEVEL LANGUAGE ROUTINES AS NEEDED... It then goes on to explain four guidelines to be observed in making the call. Everett Kaser !hplabs!hp-pcd!everett
hollen@spot.megatek.uucp (Dion Hollenbeck) (10/26/88)
From article <5876@killer.DALLAS.TX.US>, by cy@killer.DALLAS.TX.US (Cyrus Foughty): > > I have a assembly language program from which I want to > call a "C" function. I know this is backwards from what > everyone else does. BTW, I am using Microsoft Masm and > "C" 5.1 for this little dodad. [...stuff deleted...] > How do I do it? The key is in the mixed language section of the C reference manual, although it is implied rather than stated exactly. You need to know that a C function pushes its parameters on the stack from right to left. Byte width parameters are pushed as words with high order bits zeroed and long width (32-bits) parameters are pushed high 16-bits first and low 16-bits second. The calling assembly is responsible for stripping the pushed parms off the stack on return from the called function. I recommend using "ADD SP,xxx" where xxx = number of words to strip from stack (remember bytes went on stack as words). Dion Hollenbeck (619) 455-5590 x2814 Megatek Corporation, 9645 Scranton Road, San Diego, CA 92121 seismo!s3sun!megatek!hollen ames!scubed/
pozar@hoptoad.uucp (Tim Pozar) (10/27/88)
In article <5876@killer.DALLAS.TX.US> cy@killer.DALLAS.TX.US (Cyrus Foughty) writes: > I have a assembly language program from which I want to > call a "C" function. I know this is backwards from what > everyone else does. BTW, I am using Microsoft Masm and > "C" 5.1 for this little dodad. THE Microsoft manuals tell > how to interface an assembly language routine but not the > other way round. I would be forced to change ALL my assembly > programs to match what "C" wants and that is not an option. > I have way to much assembly to change. How do I do it? You have the information you need. When Microsoft describes how to call assembly functions, what they are also saying is how to call C functions too. How arguments are passed to assembly funtions is how they work for C functions. Tim -- ...sun!hoptoad!\ Tim Pozar >fidogate!pozar Fido: 1:125/406 ...lll-winken!/ PaBell: (415) 788-3904 USNail: KKSF / 77 Maiden Lane / San Francisco CA 94108