Hi Guys,
We have finished the conversion of the assembler modules in Mesa to
separate NASM'able .asm files, that work correctly with our compilers
for all the platforms we support (DOS, Win32, OS/2, Linux, QNX and
embedded systems). We have some new changes that were checked in this
week to get included, but all the code is converted and working
properly. I will be submitting those changes to CVS as soon as the
CVS server is back up.
I would like to re-open the issue of switching to using NASM
exclusively for all the assembler modules used in Mesa. There are a
number of important reasons for this:
1. The current assyntax.h mechanism is simply not portable. This
mechanism relies on the availability of a *working* C pre-processor,
and this is unfortunately not a luxury available on the DOS, Windows
and OS/2 platforms. Many compilers we use (Watcom C++ and Borland C++
specifically) do not handle C pre-processing very well, and did not
work with the assyntax.h stuff. Visual C++ worked the best, and that
is what we used to do the conversion.
2. The current mechanism to get NASM'able assembler code simply did
not work. We tried to use it, and modified the macros as much as we
could to make it work, but the resulting assembler code would not
build. Instead we had to hand modify the code from the Visual C++ pre-
processed variants, which is what we will be checking in.
3. Using our freely available macro package (one file; scitech.mac)
the NASM assembler code can use named function arguments, named local
variables and clean interfacing to different C compilers (which have
varying requirements for leading underscores for function names and
variables, something not handled by the current incarnation of
assyntax.h). Hence the existing code can be augmented to aid better
understanding by using the power of a real macro assembler.
4. NASM can produce debug information in the object files (currently
only for Borland C++ and Watcom C++, but GNU support is in the
works). This makes it a *lot* easier to debug assembler code modules
than looking at plain old dissassembly.
5. NASM is available in source form, and hence is available
anywhere. We have pre-built binaries for DOS, Win32, OS/2, Linux and
QNX, and we have never had a problem building the sources. Hence the
NASM solution is entirely portable and will work on multiple
platforms.
For the above reasons I am strongly recommending that the existing
assyntax.h style assembler code be dropped in favour of the NASM
versions.
NOTE: I am currently struggling with the CPP issues for the XFree86
port to Win32, as the entire Imake system depends on a working C pre-
processor as well. For this task we will probably be building a pre-
built imake.exe program for all supported compilers that uses the GNU
C pre-processor (the only one that seems to work reliably!).
Regards,
+---------------------------------------------------------------+
| SciTech Software - Building Truly Plug'n'Play Software! |
+---------------------------------------------------------------+
| Kendall Bennett | Email: [EMAIL PROTECTED] |
| Director of Engineering | Phone: (530) 894 8400 |
| SciTech Software, Inc. | Fax : (530) 894 9069 |
| 505 Wall Street | ftp : ftp.scitechsoft.com |
| Chico, CA 95928, USA | www : http://www.scitechsoft.com |
+---------------------------------------------------------------+
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