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/* $OpenBSD: memprobe.c,v 1.11 1997/09/02 17:00:42 mickey Exp $ */
/*
* Copyright (c) 1997 Tobias Weingartner
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Tobias Weingartner.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/param.h>
#include <machine/biosvar.h>
#include "libsa.h"
static int addrprobe __P((int));
void
memprobe()
{
int ram;
__asm __volatile(DOINT(0x12) : "=a" (BIOS_vars.bios_cnvmem)
:: "%ecx", "%edx", "cc");
BIOS_vars.bios_cnvmem &= 0xffff;
printf("%d Kb conventional memory.\n", BIOS_vars.bios_cnvmem);
/* probe extended memory
*
* There is no need to do this in assembly language. This is
* much easier to debug in C anyways.
*/
for(ram = 1024; ram < 512*1024; ram += 4){
if(!(ram % 64))
printf("Probing memory: %d KB\r", ram-1024);
if(addrprobe(ram))
break;
}
printf("%d Kb extended memory.\n", ram-1024);
BIOS_vars.bios_extmem = ram - 1024;
}
/* addrprobe(kloc): Probe memory at address kloc * 1024.
*
* This is a hack, but it seems to work ok. Maybe this is
* the *real* way that you are supposed to do probing???
*
* Modify the original a bit. We write everything first, and
* then test for the values. This should croak on machines that
* return values just written on non-existent memory...
*
* BTW: These machines are pretty broken IMHO.
*/
static int addrprobe(int kloc){
volatile int *loc, i;
static const int pat[] = {
0x00000000, 0xFFFFFFFF,
0x01010101, 0x10101010,
0x55555555, 0xCCCCCCCC
};
/* Get location */
loc = (int *)(kloc * 1024);
/* Probe address */
for(i = 0; i < NENTS(pat); i++){
*loc = pat[i];
if(*loc != pat[i])
return (1);
}
/* Write address */
for(i = 0; i < NENTS(pat); i++)
loc[i] = pat[i];
/* Read address */
for(i = 0; i < NENTS(pat); i++)
if(loc[i] != pat[i])
return (1);
return (0);
}
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