/*

CPU.c - program to write current CPUs in use to stdout

Ethan Dicks
based upon WhatCPU by Dave Haynie

Version 2.1
(c) 26-Feb-1990

This program is *not* in the public domain, but may be freely
redistributed on the condition that it is not sold, nor used in any
commercial or shareware package without the express written permission
of the author.  This program may be included in a freely redistributable
library, including, but not limited to the Fred Fish library collection.
In other words, selling this program is right out, but giving it away is
encouraged.

This program is an example of a standalone C module.  As of March 1989,
one of the discussions on comp.sys.amiga has been regarding writing C
without linking in startup code, such as AStartup.obj or c.o, and without
linking in libraries, such as Amiga.lib.  This program is one example.  It
is, however, bizarre, due to several shortcuts to shrink the size.  There
have been many odd techniques used to cut corners, including assumptions
about the content of the output, strange char array manipulation, and
unusual register defines.  While the program could be clearer, it probably
can't be made smaller.  The purpose of this program is not to be a good
example, but, rather, to be an example of TIGHT C code.

COMPILATION INSTRUCTIONS:

This code has been tested under Lattice 5.04, but will probably compile
under Lattice 4.x as well.

To compile, either use LMK and the provided Makefile, or use the commands:

lc -b -r -v -y CPU.c
blink CPU.o to CPU SC SD ND
*/

#include <exec/types.h>
#include <exec/execbase.h>
#include <libraries/dos.h>
#include <proto/exec.h>
#include <proto/dos.h>
/* This is all there is */


/* Define the processor type strings */
char	banner[] = "System Configuration: 680";
char	id_68000[] = "00";
char	id_68010[] = "10";
char	id_68020[] = "20";

char	id_68881[] = "68881";

char	crlf[]	= "\n";

/* Here goes nuthin... */
void _main()
{

/* set up Intuition/AmigaDOS structure pointers */
   struct DOSBase *DOSBase;
   struct ExecBase **SysBase;
   register struct ExecBase *ExecBase;

/* define other variables as registers, to save space */
   register int attnflag;	/* processor type bits from ExecBase struct */
   register ULONG stdout;	/* file handle of stdout */
   register char *proc;		/* pointer to processor type string */

/* Set up the ExecBase pointer manually, since we don't link with anybody */
   SysBase = (struct ExecBase **) (4L);	
   ExecBase = *SysBase;

/* Open the DOS library, since there is no one to do it for us */
   DOSBase = (struct DOSBase *)OpenLibrary(DOSNAME, 0);

/* Get the stdout filehandle */
   stdout = Output();

/* Start printing */
   Write(stdout, banner, sizeof(banner));

/* Only read the ExecBase structure once, to save space */
   attnflag = ExecBase -> AttnFlags;

   if (attnflag & AFF_68020)
   {
	proc = id_68020;	/* point to string "20" */
   }
   else
   {
	if (attnflag & AFF_68010)
	{
	proc = id_68010;	/* point to string "10" */
	}
	else
	{
	proc = id_68000;	/* point to string "00" */
	}
   }

/* Write out the processor type string - always 2 chars */
   Write(stdout, proc, 2);

   /* check for math co-processor */
   if (attnflag & AFF_68881)
   {
	Write(stdout, id_68881, sizeof(id_68881));
   }

   /* terminate the line */
   Write(stdout, crlf, sizeof(crlf));

/* Clean up and go home */
   (void) CloseLibrary(DOSBase);

}