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Help Counting RAM
Posted: Mon Jul 21, 2003 7:42 pm
by TheChuckster
Hello. I cannot compile my memory counting code and I can't seem to figure it out. Here is the code:
Code: Select all
void K_initmemman(void)
{
register unsigned long *mem;
unsigned long mem_count, a;
unsigned short memkb;
unsigned char irq1, irq2;
unsigned long cr0;
unsigned long mem_end, bse_end;
/* 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 -- LINE 73 IS NEXT!!!
__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+) -- LINE 81 IS NEXT!!!
__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);
// LINE 110 IS NEXT!!!
__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);
kprintf("Mem: %d", mem_count);
}
And here is the DJGPP output:
Code: Select all
kernel.c: In function `K_initmemman':
kernel.c:73: syntax error before ':' token
kernel.c:81: syntax error before ':' token
kernel.c:110: syntax error before ':' token
I have commented in the code where these lines occur.
Thanks in advance for your help!
Re:Help Counting RAM
Posted: Mon Jul 21, 2003 8:05 pm
by pleasepaymybills
Here is an application that will get the RAM:
CLS
PRINT "How much RAM is installed?"
INPUT HOWMUCHRAM
'GOT RAM!
Re:Help Counting RAM
Posted: Mon Jul 21, 2003 8:07 pm
by TheChuckster
Should I keep my sanity and let the mods here deal with this or cuss him out?
Re:Help Counting RAM
Posted: Mon Jul 21, 2003 8:09 pm
by pleasepaymybills
IT WORKS! IWROTE IT IN QBASIC! Do you want the binary? IT REALLY WORKS! You doubt that it works?!
Re:Help Counting RAM
Posted: Mon Jul 21, 2003 10:16 pm
by bkilgore
TheChuckster wrote:
Code: Select all
// store a copy of CR0 -- LINE 73 IS NEXT!!!
__asm__ __volatile("movl %%cr0, %%eax":"=a"(cr0))::"eax");
I had to look carefully, but I noticed on this line that you close all of the parentheses before the second colon.
__asm__ __volatile("movl %%cr0, %%eax":"=a"(cr0)
)::"eax");
That bold parenthesis is closing the parenthesis following volatile, which you don't want. If you count, you'll notice you have a total of two opening and three closing parens. Also, note that there should be two more underscores after volatile, so it should be __volatile
__
Hope this helps...
- Brandon
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 12:59 am
by The Pro from Dover
Just as a minor note, it may have been useful to use [tt]#line[/tt] directives rather than comments, in this case, as it would allow you to more specifically indicate the error locations, like this:
Code: Select all
#line 1 "store_cr0.c"
// 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");
#line 1 "disable_cache.c"
// 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");
This would have returned error codes something like this:
Code: Select all
kernel.c: In function `K_initmemman':
store_cr0.c:1: syntax error before ':' token
disable_cache.c:1: syntax error before ':' token
Just a suggestion, of course; use whatever works for you. HTH.
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 9:17 am
by TheChuckster
Ok, that's all sorted out. Any reason why
Code: Select all
kernel.c:73: can't find a register in class `AREG' while reloading `asm'
kernel.c:81: can't find a register in class `AREG' while reloading `asm'
kernel.c:110: can't find a register in class `AREG' while reloading `asm'
?
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 11:00 am
by gedeon
The same function a little bit modified
it works
Code: Select all
int count_memory(void)
{
register unsigned long *mem;
unsigned long bse_end;
unsigned long mem_count;
unsigned long a;
unsigned short memkb;
unsigned long mem_end;
mem_count=0;
memkb=0;
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);
mem_end=memkb<<20;
mem=(unsigned long*)0x413;
bse_end=((*mem)&0xFFFF)<<6;
return memkb;
}
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 1:30 pm
by bkilgore
TheChuckster wrote:
Ok, that's all sorted out. Any reason why
Code: Select all
kernel.c:73: can't find a register in class `AREG' while reloading `asm'
kernel.c:81: can't find a register in class `AREG' while reloading `asm'
kernel.c:110: can't find a register in class `AREG' while reloading `asm'
?
I'm not sure the exact details, but basically it's because you're clobbering eax, and the compiler wants it. Why not just let gcc pick a register for you instead of forcing eax? Change the three lines to those that follow:
Code: Select all
// store a copy of CR0 -- LINE 73 IS NEXT!!!
__asm__ __volatile__("movl %%cr0, 0":"=g"(cr0));
Code: Select all
// cache disable(486+), no-writeback(486+), 32bit mode(386+) -- LINE 81 IS NEXT!!!
__asm__ __volatile__("movl %0, %%cr0" :: "g" (cr0 | 0x00000001 | 0x40000000 | 0x20000000));
Code: Select all
// LINE 110 IS NEXT!!!
__asm__ __volatile__("movl %0, %%cr0" :: "g" (cr0));
Let me know if that works...
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 2:38 pm
by Pype.Clicker
TheChuckster wrote:
Ok, that's all sorted out. Any reason why
Code: Select all
kernel.c:73: can't find a register in class `AREG' while reloading `asm'
kernel.c:81: can't find a register in class `AREG' while reloading `asm'
kernel.c:110: can't find a register in class `AREG' while reloading `asm'
?
not sure, but it looks strange to me that you have "eax" declared as "clobbered register' and as "output register". It doesn't sound like a good idea to me ...
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 5:26 pm
by TheChuckster
gedeon: Your function does not work. It returns that I have 64kb, when in fact, I have 256 MB of RAM.
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 5:48 pm
by TheChuckster
:-[ AHHH NO! Don't correct me... I feel foolish. I had Bochs set up to emulate 64 MB. No wonder the value was so low! *bangs head on desk repeatedly*
Re:Help Counting RAM
Posted: Tue Jul 22, 2003 6:40 pm
by Tux
While I was searching for tutorials, I found this page. If you want a memory probing function, here it is:
Code: Select all
//PC.h HALfix/PolarOS core
//Defects: doesn't detect memory wraps!!
int getmemory()
{
int where=0x200000;
char save;
for(;;)
{
char * point=(char *) where;
save=point[0];
point[0]='L'; //L is for Linux :)
if(point[0]=='L')
{
point[0]=save;
where+=0x100000;
}
else
{
point[0]=save;
return where;
}
}
}