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win32gc.c
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00001 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
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00015  * The Original Code is the Netscape Portable Runtime (NSPR).
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00024  * Alternatively, the contents of this file may be used under the terms of
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00037 
00038 /*
00039  * GC related routines
00040  *
00041  */
00042 #include <windows.h>
00043 #include "prlog.h"
00044 
00045 extern PRLogModuleInfo* _pr_msgc_lm;
00046 
00047 #define GC_VMBASE               0x40000000
00048 #define GC_VMLIMIT              0x00FFFFFF
00049 
00050 /************************************************************************/
00051 /*
00052 ** Machine dependent GC Heap management routines:
00053 **    _MD_GrowGCHeap
00054 */
00055 /************************************************************************/
00056 
00057 void *baseaddr = (void*) GC_VMBASE;
00058 void *lastaddr = (void*) GC_VMBASE;
00059 
00060 void _MD_InitGC() {}
00061 
00062 void *_MD_GrowGCHeap(PRUint32 *sizep)
00063 {
00064     void *addr;
00065     size_t size;
00066 
00067     /* Reserve a block of memory for the GC */
00068     if( lastaddr == baseaddr ) {
00069         addr = VirtualAlloc( (void *)GC_VMBASE, GC_VMLIMIT, MEM_RESERVE, PAGE_READWRITE );
00070 
00071         /* 
00072         ** If the GC_VMBASE address is already mapped, then let the OS choose a 
00073         ** base address that is available...
00074         */
00075         if (addr == NULL) {
00076             addr = VirtualAlloc( NULL, GC_VMLIMIT, MEM_RESERVE, PAGE_READWRITE );
00077 
00078             baseaddr = lastaddr = addr;
00079             if (addr == NULL) {
00080                 PR_LOG(_pr_msgc_lm, PR_LOG_ALWAYS, ("GC: unable to allocate heap: LastError=%ld",
00081                        GetLastError()));
00082                 return 0;
00083             }
00084         }
00085     }
00086     size = *sizep;
00087 
00088     /* Extend the mapping */
00089     addr = VirtualAlloc( lastaddr, size, MEM_COMMIT, PAGE_READWRITE );
00090     if (addr == NULL) {
00091         return 0;
00092     }
00093 
00094     lastaddr = ((char*)addr + size);
00095     PR_LOG(_pr_msgc_lm, PR_LOG_ALWAYS,
00096           ("GC: heap extends from %08x to %08x",
00097            baseaddr, (long)baseaddr + (char*)lastaddr - (char*)baseaddr));
00098 
00099     return addr;
00100 }
00101 
00102 PRBool _MD_ExtendGCHeap(char *base, PRInt32 oldSize, PRInt32 newSize) {
00103   void* addr;
00104 
00105   addr = VirtualAlloc( base + oldSize, newSize - oldSize,
00106                      MEM_COMMIT, PAGE_READWRITE );
00107   if (NULL == addr) {
00108     PR_LOG(_pr_msgc_lm, PR_LOG_ALWAYS, ("GC: unable to extend heap: LastError=%ld",
00109                    GetLastError()));
00110     return PR_FALSE;
00111   }
00112   if (base + oldSize != (char*)addr) {
00113     PR_LOG(_pr_msgc_lm, PR_LOG_ALWAYS, ("GC: segment extension returned %x instead of %x",
00114                    addr, base + oldSize));
00115     VirtualFree(addr, newSize - oldSize, MEM_DECOMMIT);
00116     return PR_FALSE;
00117   }
00118   lastaddr = base + newSize;
00119   PR_LOG(_pr_msgc_lm, PR_LOG_ALWAYS,
00120         ("GC: heap now extends from %p to %p",
00121          base, base + newSize));
00122   return PR_TRUE;
00123 }
00124 
00125 
00126 void _MD_FreeGCSegment(void *base, PRInt32 len)
00127 {
00128      (void)VirtualFree(base, 0, MEM_RELEASE);
00129 }