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/*
Copyright (c) 2008 TrueCrypt Developers Association. All rights reserved.
Governed by the TrueCrypt License 3.0 the full text of which is contained in
the file License.txt included in TrueCrypt binary and source code distribution
packages.
*/
#include "BootDefs.h"
#include "BootMemory.h"
static uint32 MemoryMapContValue;
static bool GetMemoryMapEntry (BiosMemoryMapEntry &entry)
{
static const uint32 function = 0x0000E820UL;
static const uint32 magic = 0x534D4150UL;
static const uint32 bufferSize = sizeof (BiosMemoryMapEntry);
bool carry = false;
uint32 resultMagic;
uint32 resultSize;
__asm
{
push es
lea di, function
TC_ASM_MOV_EAX_DI
lea di, MemoryMapContValue
TC_ASM_MOV_EBX_DI
lea di, bufferSize
TC_ASM_MOV_ECX_DI
lea di, magic
TC_ASM_MOV_EDX_DI
lea di, MemoryMapContValue
TC_ASM_MOV_DI_ECX
// Use alternative segment to prevent memory corruption caused by buggy BIOSes
push TC_BOOT_LOADER_ALT_SEGMENT
pop es
mov di, 0
int 0x15
jnc no_carry
mov carry, true
no_carry:
lea di, resultMagic
TC_ASM_MOV_DI_EAX
lea di, MemoryMapContValue
TC_ASM_MOV_DI_EBX
lea di, resultSize
TC_ASM_MOV_DI_ECX
pop es
}
CopyMemory (TC_BOOT_LOADER_ALT_SEGMENT, 0, &entry, sizeof (entry));
// BIOS may set CF at the end of the list
if (carry)
MemoryMapContValue = 0;
return resultMagic == magic && resultSize == bufferSize;
}
bool GetFirstBiosMemoryMapEntry (BiosMemoryMapEntry &entry)
{
MemoryMapContValue = 0;
return GetMemoryMapEntry (entry);
}
bool GetNextBiosMemoryMapEntry (BiosMemoryMapEntry &entry)
{
if (MemoryMapContValue == 0)
return false;
return GetMemoryMapEntry (entry);
}
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