TD3:I5 Implement PageProvide, untested for now

code/Makefile.common

@@ -31,7 +31,8 @@ THREAD_O	:=	main.o list.o scheduler.o synch.o synchlist.o \
 			stats.o sysdep.o timer.o
 
 USERPROG_O	:=	addrspace.o bitmap.o exception.o progtest.o console.o \
-				consoledriver.o machine.o mipssim.o translate.o userthread.o
+				consoledriver.o machine.o mipssim.o translate.o \
+				userthread.o papeprovider.o
 
 VM_O		:=
 

code/machine/machine.cc

@@ -61,6 +61,10 @@ Machine::Machine(bool debug)
     mainMemory = new char[MemorySize];
     for (i = 0; i < MemorySize; i++)
       	mainMemory[i] = 0;
+    #ifdef CHANGED
+    pageProvider = new PageProvider((int)(MemorySize/PageSize));
+    #endif
+    DEBUG ('a', "Allocated page: %i\n", page);
 #ifdef USE_TLB
     tlb = new TranslationEntry[TLBSize];
     for (i = 0; i < TLBSize; i++)

code/machine/machine.h

@@ -26,6 +26,10 @@
 #include "translate.h"
 #include "disk.h"
 
+#ifdef CHANGED
+#include "pageprovider.h"
+#endif
+
 // Definitions related to the size, and format of user memory
 
 #define PageSize 	SectorSize 	// set the page size equal to
@@ -201,7 +205,9 @@ class Machine:public dontcopythis {
 
     TranslationEntry *currentPageTable;
     unsigned int currentPageTableSize;
-
+    #ifdef CHANGED
+    PageProvider * pageProvider;
+    #endif // CHANGED
   private:
     bool singleStep;		// drop back into the debugger after each
 				// simulated instruction

code/userprog/pageprovider.cc

@@ -0,0 +1,33 @@
+#ifdef CHANGED
+#include "bitmap.h"
+#include "pageprovider.h"
+#include "system.h"
+
+PageProvider::PageProvider(int n) {
+	page = new BitMap(n);
+    page->Mark(0);
+}
+
+PageProvider::~PageProvider(){
+	delete page;
+}
+
+int PageProvider::GetEmptyPage() {
+	int page = page->Find();
+    if(emptyPage != -1)
+        return -1;
+    memset(machine->mainMemory+emptyPage * PageSize, 0, PageSize);
+    DEBUG ('a', "Allocated page: %i\n", page);
+    return page;
+}
+
+void PageProvider::ReleasePage(int n) {
+    DEBUG ('a', "Release page: %i\n", page);
+    page->Clear(n);
+}
+
+int PageProvider::NumAvailPage() {
+    return page->NumClear();
+}
+
+#endif //CHANGED

code/userprog/pageprovider.h

@@ -0,0 +1,19 @@
+#ifndef PAGEPROVIDER_H
+#define PAGEPROVIDER_H
+#ifdef CHANGED
+
+#include "bitmap.h"
+
+class PageProvider {
+public:
+	PageProvider(int n);
+	~PageProvider();
+	int GetEmptyPage();
+	void ReleasePage(int n);
+	int NumAvailPage();
+	BitMap* page;
+};
+
+#endif
+#endif // PAGEPROVIDER_H
+