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bug when dos mem resize is used to shrink memory blocks

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(QuickBasic, fixes Shard of Spring)


Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@2244
This commit is contained in:
Sebastian Strohhäcker 2005-07-20 19:20:23 +00:00
parent d0ea228182
commit 9c62fe8db2
1 changed files with 18 additions and 0 deletions
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18
src/dos/dos_memory.cpp
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@ -138,6 +138,24 @@ bool DOS_ResizeMemory(Bit16u segment,Bit16u * blocks) {
DOS_MCB mcb(segment-1);
Bit16u total=mcb.GetSize();
DOS_MCB mcb_next(segment+total);
if (*blocks<=total) {
if (GCC_UNLIKELY(*blocks==total)) {
/* Nothing to do */
return true;
}
/* Shrinking MCB */
DOS_MCB mcb_new_next(segment+(*blocks));
mcb.SetSize(*blocks);
mcb_new_next.SetType(mcb.GetType());
if (mcb.GetType()==0x5a) {
/* Further blocks follow */
mcb.SetType(0x4d);
}
mcb_new_next.SetSize(total-*blocks-1);
mcb_new_next.SetPSPSeg(MCB_FREE);
return true;
}
if (mcb.GetType()!=0x5a) {
if (mcb_next.GetPSPSeg()==MCB_FREE) {
total+=mcb_next.GetSize()+1;