add initial System module

src/core/System.cc

@@ -0,0 +1,31 @@
+#include "System.h"
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+long System::page_size;
+
+bool System::init()
+{
+    System::page_size = sysconf(_SC_PAGESIZE);
+    if ((System::page_size == 0) ||
+            (System::page_size > (2 * 1024 * 1024)) ||
+            ((System::page_size & (System::page_size - 1)) != 0))
+    {
+        printf("Unsupported page size detected: %ld\n", System::page_size);
+        return false;
+    }
+
+    return true;
+}
+
+void * System::alloc_pages(int num)
+{
+    return mmap(
+            NULL,
+            num * System::page_size,
+            PROT_READ | PROT_WRITE,
+            MAP_PRIVATE | MAP_ANONYMOUS,
+            -1,
+            0);
+}

src/core/System.h

@@ -0,0 +1,12 @@
+#ifndef SYSTEM_H
+#define SYSTEM_H
+
+class System
+{
+public:
+    static bool init();
+    static long page_size;
+    static void * alloc_pages(int num);
+};
+
+#endif

src/jes.cc

@@ -2,9 +2,15 @@
 #include "Window.h"
 #include "Runtime.h"
 #include <memory>
+#include "System.h"
 
 int main(int argc, char * argv[])
 {
+    if (!System::init())
+    {
+        return 1;
+    }
+
     Runtime::init(argv[0], APPNAME);
 
     std::shared_ptr<Buffer> b = std::make_shared<Buffer>();