/*GazOS Operating SystemCopyright (C) 1999  Gareth Owen <gaz@athene.co.uk>This program is free software; you can redistribute it and/ormodify it under the terms of the GNU General Public Licenseas published by the Free Software Foundation; either version 2of the License, or (at your option) any later version.This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with this program; if not, write to the Free SoftwareFoundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.*/#include "io.h"unsigned long mem_end, bse_end;void count_memory(void) {         register unsigned long *mem;         unsigned long mem_count, a;         unsigned short  memkb;         unsigned char   irq1, irq2;         unsigned long cr0;         /* save IRQ's */         irq1=inportb(0x21);         irq2=inportb(0xA1);         /* kill all irq's */         outportb(0x21, 0xFF);         outportb(0xA1, 0xFF);         mem_count=0;         memkb=0;         // store a copy of CR0         __asm__ __volatile("movl %%cr0, %%eax":"=a"(cr0)::"eax");         // invalidate the cache         // write-back and invalidate the cache         __asm__ __volatile__ ("wbinvd");         // plug cr0 with just PE/CD/NW         // cache disable(486+), no-writeback(486+), 32bit mode(386+)         __asm__ __volatile__("movl %%eax, %%cr0" :: "a" (cr0 | 0x00000001 | 0x40000000 | 0x20000000) : "eax");         do         {                 memkb++;                 mem_count+=1024*1024;                 mem=(unsigned long *)mem_count;                 a=*mem;                 *mem=0x55AA55AA;                                  // the empty asm calls tell gcc not to rely on whats in its registers                 // as saved variables (this gets us around GCC optimisations)                 asm("":::"memory");                 if(*mem!=0x55AA55AA)                         mem_count=0;                 else                 {                         *mem=0xAA55AA55;                         asm("":::"memory");                         if(*mem!=0xAA55AA55)                                 mem_count=0;                 }                 asm("":::"memory");                 *mem=a;         }while(memkb<4096 && mem_count!=0);         __asm__ __volatile__("movl %%eax, %%cr0" :: "a" (cr0) : "eax");         mem_end=memkb<<20;         mem=(unsigned long *)0x413;         bse_end=((*mem)&0xFFFF)<<6;         outportb(0x21, irq1);         outportb(0xA1, irq2); }