Re: [Gm2] Some Confirmation Of Recent Bug Fixes

[Christoph Schlegel]

Gaius Mulley wrote:

[snip]

> yes, thanks for asking about it as I forgot to cvs add this file.
> Here is the start of SYSTEM.c - which needs the rest of the system
> calls to be initialized. It would be great if this could be done
> during configure (or perhaps during the library build) by a script
> (python?) reading the sys/syscall.h. Then we need to modify the
> gm2 front end to automatically include the appropriate search path
> and include SYSTEM.o during linking.

I don't think it's a good idea to use Python here. Modula-2 is a
language for systems programming and I do not want to get a
Python-interpreter up and running before my Modula-2 compiler
can be built. Python is a nice language but in my case I need
a compiler which runs in a minimum environment (eg cross-compile
a small NetBSD-kernel plus basic utilities and GCC: nothing else).

> Gaius
>
> ---------------------------
> #include <sys/syscall.h>
> #include <stdarg.h>
> #include <errno.h>
>
> #if !defined(TRUE)
> #   define TRUE (1==1)
> #endif
>
> #if !defined(FALSE)
> #   define FALSE (1==0)
> #endif
>
> extern int read (int, void *, int);
> extern int write (int, void *, int);
>
> static int (*syscalls[200])();
> static int initialized = 0;
>
> int mywrite (int fd, void *buf, int len)
> {
>   return write (fd, buf, len);
> }
>
> int
> SYSTEM_UNIXCALL (int syscall, int *r0, int *r1, ...)
> {
>   va_list ap;
>   int p1, p2, p3;
>
>   if (! initialized)
>     _M2_SYSTEM_init();
>
>   va_start (ap, r1);
>   p1 = va_arg (ap, int);
>   p2 = va_arg (ap, int);
>   p3 = va_arg (ap, int);
>   *r0 = (*syscalls[syscall]) (p1, p2, p3);
>   va_end (ap);
>   return (*r0) >= 0;
> }
>
> /*
>  *  UNIXFORK - returns TRUE if successful and pid is set to the son pid
>  *             if the parent is returning. If the child is returning pid=0.
>  *             UNIXFORK returns FALSE if an error occurs and errno is held in 
> pid.
>  */
>
> int
> SYSTEM_UNIXFORK (unsigned int *pid)
> {
>   int p = fork();
>
>   if (p == -1) {
>     *pid = errno;
>     return FALSE;
>   }
>   *pid = p;
>
>   return TRUE;
> }
>
> _M2_SYSTEM_init ()
> {
>   syscalls[__NR_write] = (void *)mywrite;
>   syscalls[__NR_read]  = (void *)read;
>   initialized = 1;
> }
>
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