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Fix for alloc of 'memimage': so that two adjacent 64K regions map to same physical 64K region. Fixes #1285. (PR #1286) 

Includes platform-specific code for both Windows & Linux.
Co-authored-by: @audetto
This commit is contained in:
TomCh 2024-04-01 11:20:43 +02:00 committed by GitHub
parent d3ff855f2d
commit b00c9b0d3f
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1 changed files with 155 additions and 5 deletions
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160
source/Memory.cpp
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@ -56,9 +56,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#include "YamlHelper.h"
// In this file allocate the 64KB of RAM with aligned memory allocations (0x10000)
// to ease mapping between Apple ][ and host memory space (while debugging).
// this is not available in Visual Studio
// to ease mapping between Apple ][ and host memory space (while debugging) & also to fix GH#1285.
// This is not available in Windows CRT:
// https://en.cppreference.com/w/c/memory/aligned_alloc
#ifdef _MSC_VER
@ -66,6 +65,8 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#define ALIGNED_ALLOC(size) (LPBYTE)VirtualAlloc(NULL, size, MEM_COMMIT, PAGE_READWRITE)
#define ALIGNED_FREE(ptr) VirtualFree(ptr, 0, MEM_RELEASE)
#else
#include <unistd.h>
#include <sys/mman.h>
// use plain "new" in gcc (where debugging needs are less important)
#define ALIGNED_ALLOC(size) new BYTE[size]
#define ALIGNED_FREE(ptr) delete [] ptr
@ -242,7 +243,14 @@ static LPBYTE RWpages[kMaxExMemoryBanks]; // pointers to RW memory banks
static const UINT kNumAnnunciators = 4;
static bool g_Annunciator[kNumAnnunciators] = {};
#ifdef _MSC_VER
static HANDLE g_hMemImage = NULL; // NB. When not initialised, this handle is NULL (not INVALID_HANDLE_VALUE)
#else
static FILE * g_hMemTempFile = NULL;
#endif
BYTE __stdcall IO_Annunciator(WORD programcounter, WORD address, BYTE write, BYTE value, ULONG nCycles);
static void FreeMemImage(void);
//=============================================================================
@ -1289,7 +1297,7 @@ void MemDestroy()
{
ALIGNED_FREE(memaux);
ALIGNED_FREE(memmain);
ALIGNED_FREE(memimage);
FreeMemImage();
delete [] memdirty;
delete [] memrom;
@ -1509,12 +1517,154 @@ bool MemIsAddrCodeMemory(const USHORT addr)
//===========================================================================
static void FreeMemImage(void)
{
#ifdef _MSC_VER
if (g_hMemImage)
{
const UINT num64KPages = 2;
for (UINT i = 0; i < num64KPages; i++)
UnmapViewOfFile(memimage + i * _6502_MEM_LEN);
CloseHandle(g_hMemImage);
g_hMemImage = NULL;
}
else
{
ALIGNED_FREE(memimage);
}
#else
if (g_hMemTempFile)
{
const UINT num64KPages = 2;
for (UINT i = 0; i < num64KPages; i++)
{
munmap(memimage + i * _6502_MEM_LEN, _6502_MEM_LEN);
}
// with the following line, SDL_Quit() segfaults ????
// munmap(memimage + num64KPages * _6502_MEM_LEN, _6502_MEM_LEN);
fclose(g_hMemTempFile);
g_hMemTempFile = NULL;
}
else
{
ALIGNED_FREE(memimage);
}
#endif
}
static LPBYTE AllocMemImage(void)
{
#ifdef _MSC_VER
LPBYTE baseAddr = NULL;
// Allocate memory for 'memimage' (and the alias 'mem')
// . Setup so we have 2 consecutive virtual 64K regions pointing to the same physical 64K region.
// . This is a fix (and optimisation) for 6502 opcodes that do a 16-bit read at 6502 address $FFFF. (GH#1285)
SYSTEM_INFO info;
GetSystemInfo(&info);
bool res = (info.dwAllocationGranularity == _6502_MEM_LEN);
if (res)
{
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 == 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)
{
// 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();
}
while (retry--);
#if 1
if (res) // test
{
baseAddr[0x0000] = 0x11;
baseAddr[0xffff] = 0x22;
USHORT value = *((USHORT*)(baseAddr + 0xffff));
_ASSERT(value == 0x1122);
}
#endif
}
else
{
LogFileOutput("MemInitialize: SYSETEM_INFO.wAllocationGranularity = 0x%08X.\n", info.dwAllocationGranularity);
}
if (!res)
{
LogFileOutput("MemInitialize: Failed to map 2 adjacent virtual 64K pages (reverting to old method).\n");
baseAddr = ALIGNED_ALLOC(_6502_MEM_LEN);
}
return baseAddr;
#else
g_hMemTempFile = tmpfile();
if (g_hMemTempFile)
{
const int fd = fileno(g_hMemTempFile);
if (!ftruncate(fd, _6502_MEM_LEN))
{
const UINT num64KPages = 2;
LPBYTE baseAddr = static_cast<LPBYTE>(mmap(NULL, num64KPages * _6502_MEM_LEN, PROT_NONE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0));
if (baseAddr)
{
for (UINT i = 0; i < num64KPages; i++)
{
// can this ever fail?
mmap(baseAddr + i * _6502_MEM_LEN , _6502_MEM_LEN, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, fd, 0);
}
// we could fclose the file here
// but we keep it as a reminder of how to free the memory later
return baseAddr;
}
}
fclose(g_hMemTempFile);
g_hMemTempFile = NULL;
}
LogFileOutput("MemInitialize: Failed to map 2 adjacent virtual 64K pages (reverting to old method).\n");
return ALIGNED_ALLOC(_6502_MEM_LEN);
#endif
}
//===========================================================================
void MemInitialize()
{
// ALLOCATE MEMORY FOR THE APPLE MEMORY IMAGE AND ASSOCIATED DATA STRUCTURES
memaux = ALIGNED_ALLOC(_6502_MEM_LEN); // NB. alloc even if model is Apple II/II+, since it's used by VidHD card
memmain = ALIGNED_ALLOC(_6502_MEM_LEN);
memimage = ALIGNED_ALLOC(_6502_MEM_LEN);
memimage = AllocMemImage();
memdirty = new BYTE[0x100];
memrom = new BYTE[0x3000 * MaxRomPages];