From 33613a85afc4b1481367fbe92a17ee59c240250b Mon Sep 17 00:00:00 2001
From: Sven Eisenhauer <sven@sven-eisenhauer.net>
Date: Fri, 10 Nov 2023 15:11:48 +0100
Subject: add new repo

---
 .../ARM202U/EXAMPLES/CLSTAND/MEMTEST.C             | 89 ++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 Bachelor/Mikroprozessorsysteme2/ARM202U/EXAMPLES/CLSTAND/MEMTEST.C

(limited to 'Bachelor/Mikroprozessorsysteme2/ARM202U/EXAMPLES/CLSTAND/MEMTEST.C')

diff --git a/Bachelor/Mikroprozessorsysteme2/ARM202U/EXAMPLES/CLSTAND/MEMTEST.C b/Bachelor/Mikroprozessorsysteme2/ARM202U/EXAMPLES/CLSTAND/MEMTEST.C
new file mode 100644
index 0000000..46e8f1a
--- /dev/null
+++ b/Bachelor/Mikroprozessorsysteme2/ARM202U/EXAMPLES/CLSTAND/MEMTEST.C
@@ -0,0 +1,89 @@
+/*
+ * Standalone run-time system test.
+ *
+ * This program checks that stack overflow checking works and that it
+ * interacts properly with heap extension.
+ *
+ * Copyright (C) 1991 Advanced RISC Machines Limited.
+ */
+
+#include "rtstand.h"
+
+extern void __swi(0) put_char(int ch);
+extern void __swi(2) put_string(char *string);
+
+/* First, we make a function to claim a large(-ish) stack frame.
+ * Some obfuscation in case the compiler optimises us away...
+ */
+static int stack(int n, int v) {
+  /* claim n KB of stack */
+  int x[256],i;
+
+  if (n > 1) v = stack(n-1, v);
+  for (i = 0;  i < 256;  ++i) x[i] = v + i;
+  return x[0] + x[255];
+}
+
+/* Now we roll our own decimal output function - strictly %d format...
+ */
+static void puti(int n) {
+  if (n < 0) {
+    put_char('-');
+    n = -n;
+  }
+  if (n > 9) {
+    int n1 = n / 10;
+    n = n % 10;
+    puti(n1);
+  }
+  put_char(n + '0');
+}
+ 
+/* ...and a hex outputter... strictly %#.8X format.
+ */
+static void puth(unsigned n) {
+  int j;
+  put_string("0X");
+  for (j = 0;  j < 8;  ++j) {
+     put_char("0123456789ABCDEF"[n >> 28]);
+     n <<= 4;
+  }
+}
+
+/* Finally, we sit in a loop extending the heap and claiming ever bigger
+ * stack franes until something gives. Probably, the heap will give first,
+ * as currently tuned, and the program will announce "memory exhausted".
+ * If you tune it differently, it can be made to fail will a stack overflow
+ * run-time error. Try compiling this -DSTACK_OVERFLOW to provoke it.
+ */
+int main(int argc, char *argv[]) {
+  unsigned size, ask, got, total;
+  void *base;
+
+  put_string("kernel memory management test\r\n");
+
+  size = 4;  /* KB */
+  ask = 0;
+  for (total = 0;;) {
+    put_string("force stack to "); puti(size);  put_string("KB\r\n");
+    stack(size, 0);
+    put_string("request "); puti(ask);  put_string(" words of heap - ");
+    got = __rt_alloc(ask, &base);
+    total += got;
+    put_string("allocate "); puti(got);
+    put_string(" words at "); puth((unsigned)base); put_string("\r\n");
+    if (got < ask) break;
+    ask += got / 2;
+#ifdef STACK_OVERFLOW
+    size *= 2;
+#else
+    size += 4;
+#endif
+  }
+
+  put_string("memory exhausted, ");
+  puti(total); put_string(" words of heap, ");
+  puti(size);  put_string("KB of stack\r\n"); 
+
+  return 0;
+}
-- 
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