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Fixed some problems in memory probe.

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This commit is contained in:
erich 1996-10-06 03:06:41 +00:00
parent 9a37393599
commit d30c778c28
1 changed files with 66 additions and 52 deletions
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118
shared_src/common.c
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@ -30,7 +30,6 @@ struct multiboot_info mbi;
unsigned long saved_drive;
unsigned long saved_partition;
unsigned long saved_mem_upper;
int mem_map = 0;
/*
* Error code stuff.
@ -90,6 +89,8 @@ static struct AddrRangeDesc fakemap[3] =
void
init_bios_info(void)
{
int cont, memtmp, addr;
/*
* Get information from BIOS on installed RAM.
*/
@ -107,71 +108,84 @@ init_bios_info(void)
gateA20(1);
/*
* The "mem_upper" variable only recognizes upper memory in the
* The "mbi.mem_upper" variable only recognizes upper memory in the
* first memory region. If there are multiple memory regions,
* the rest are reported to a Multiboot-compliant OS, but otherwise
* unused by GRUB.
*/
{
int cont = 0, mem1, mem2, addr;
mbi.mmap_addr = (addr = (((int) end) & ~3) + 4);
mbi.mmap_length = 0;
cont = 0;
mbi.mmap_addr = (addr = (((int) end) & ~3) + 4);
mbi.mmap_length = 0;
do
{
cont = get_mem_map(addr, cont);
do
{
cont = get_mem_map(addr, cont);
if ( ! *((int *)addr) )
break;
if ( ! *((int *)addr) )
break;
mbi.mmap_length += *((int *)addr) + 4;
addr += *((int *)addr) + 4;
}
while (cont);
/*
* This is to get the upper memory up to the first memory
* hole into the "mbi.mem_upper" element, for OS's that
* don't care about the memory map, but might care about
* RAM above 64MB.
*/
if (((struct AddrRangeDesc *)addr)->BaseAddrLow == 0x100000
&& ((struct AddrRangeDesc *)addr)->BaseAddrHigh == 0
&& ((struct AddrRangeDesc *)addr)->Type == MB_ARD_MEMORY)
{
/* limit to 4G, as most OS's would probably break with more */
if (mbi.mmap_length)
{
/*
* This is to get the upper memory up to the first memory
* hole into the "mbi.mem_upper" element, for OS's that
* don't care about the memory map, but might care about
* RAM above 64MB.
*
* A big problem is that the memory areas aren't guaranteed
* to be: (1) contiguous, (2) sorted in ascending order, or
* (3) non-overlapping.
*/
memtmp = 0x100000;
if (!((struct AddrRangeDesc *)addr)->LengthHigh)
mbi.mem_upper = ((struct AddrRangeDesc *)addr)->LengthLow >> 10;
else
mbi.mem_upper = 0x3FBFC0; /* 4G - 1M - 64K */
}
do
{
for (cont = 0, addr = mbi.mmap_addr;
addr < mbi.mmap_addr + mbi.mmap_length;
addr += *((int *) addr) + 4)
{
if (((struct AddrRangeDesc *)addr)->BaseAddrHigh == 0
&& ((struct AddrRangeDesc *)addr)->Type == MB_ARD_MEMORY
&& ((struct AddrRangeDesc *)addr)->BaseAddrLow <= memtmp
&& (((struct AddrRangeDesc *)addr)->BaseAddrLow
+ ((struct AddrRangeDesc *)addr)->LengthLow) > memtmp)
{
memtmp = (((struct AddrRangeDesc *)addr)->BaseAddrLow
+ ((struct AddrRangeDesc *)addr)->LengthLow);
cont++;
}
}
}
while (cont);
mbi.mmap_length += *((int *)addr) + 4;
addr += *((int *)addr) + 4;
mbi.mem_upper = (memtmp - 0x100000) >> 10;
}
else if ((memtmp = get_eisamemsize()) != -1)
{
cont = memtmp & ~0xFFFF;
memtmp = memtmp & 0xFFFF;
mem_map++;
}
while (cont);
if (!cont || (memtmp == 0x3c00))
memtmp += (cont >> 10);
else
{
/* XXX should I do this at all ??? */
if (!mem_map && (mem1 = get_eisamemsize()) != -1)
{
mem2 = mem1 >> 16;
mem1 &= 0xFFFF;
mbi.mem_upper = mem1;
mbi.mmap_addr = (int)fakemap;
mbi.mmap_length = sizeof(fakemap);
fakemap[0].LengthLow = (mbi.mem_lower << 10);
fakemap[1].LengthLow = (memtmp << 10);
fakemap[2].LengthLow = cont;
}
if (!mem2 || (mem1 == 0x3c00))
mbi.mem_upper += (mem2 << 6);
else
{
/* XXX should I do this at all ??? */
mbi.mmap_addr = (int)fakemap;
mbi.mmap_length = sizeof(fakemap);
fakemap[0].LengthLow = (mbi.mem_lower << 10);
fakemap[1].LengthLow = (mem1 << 10);
fakemap[2].LengthLow = (mem2 << 16);
mem_map++;
}
}
}
mbi.mem_upper = memtmp;
}
saved_mem_upper = mbi.mem_upper;