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Simplify mapping code

This commit is contained in:
tomcw 2024-03-29 22:02:36 +00:00
parent 578271ea8a
commit 443d9cad10
1 changed files with 25 additions and 27 deletions
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52
source/Memory.cpp
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@ -1548,41 +1548,39 @@ static LPBYTE AllocMemImage(void)
if (res)
{
res = false;
const UINT num64KRegions = 2;
UINT retry = 10;
do
{
res = false;
const UINT num64KRegions = 2;
const SIZE_T totalVirtualSize = _6502_MEM_LEN * num64KRegions;
baseAddr = (LPBYTE)VirtualAlloc(0, totalVirtualSize, MEM_RESERVE, PAGE_NOACCESS);
if (baseAddr)
if (baseAddr == NULL)
break;
VirtualFree(baseAddr, 0, MEM_RELEASE);
// Create a file mapping object of [64K] size that is backed by the system paging file.
g_hMemImage = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, _6502_MEM_LEN, NULL);
// NB. Returns NULL on failure (not INVALID_HANDLE_VALUE)
if (g_hMemImage == NULL)
break;
UINT count = 0;
while (count < num64KRegions)
{
VirtualFree(baseAddr, 0, MEM_RELEASE);
// Create a file mapping object of [64K] size that is backed by the system paging file.
g_hMemImage = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, _6502_MEM_LEN, NULL);
// NB. Returns NULL on failure (not INVALID_HANDLE_VALUE)
if (g_hMemImage == NULL)
// MSDN: "To specify a suggested base address for the view, use the MapViewOfFileEx function. However, this practice is not recommended."
// The OS (ie. another process) may've beaten us to this suggested baseAddr. This is why we retry multiple times.
if (!MapViewOfFileEx(g_hMemImage, FILE_MAP_ALL_ACCESS, 0, 0, _6502_MEM_LEN, baseAddr + count * _6502_MEM_LEN))
break;
UINT count = 0;
while (count < num64KRegions)
{
// MSDN: "To specify a suggested base address for the view, use the MapViewOfFileEx function. However, this practice is not recommended."
// The OS (ie. another process) may've beaten us to this suggested baseAddr. This is why we retry multiple times.
if (!MapViewOfFileEx(g_hMemImage, FILE_MAP_ALL_ACCESS, 0, 0, _6502_MEM_LEN, baseAddr + count * _6502_MEM_LEN))
break;
count++;
}
res = (count == num64KRegions);
if (res)
break;
// Failed this time, so clean-up and retry...
FreeMemImage();
count++;
}
res = (count == num64KRegions);
if (res)
break;
// Failed this time, so clean-up and retry...
FreeMemImage();
}
while (retry--);