Add BSP and semihosting library for nios2-generic-nommu QEMU emulation.

libgloss/nios2/sbrk.c

@@ -0,0 +1,42 @@
+/*
+ * sbrk.c
+ *
+ * Copyright (c) 2018 Mentor Graphics
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions. No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+
+#include <errno.h>
+/*
+ * sbrk -- changes heap size size. Get nbytes more
+ *         RAM. We just increment a pointer in what's
+ *         left of memory on the board.
+ */
+
+/* Provided by the linker script.  */
+extern char __heap_start[] __attribute__ ((aligned (8)));
+extern char __heap_end[] __attribute__ ((aligned (8)));
+
+void *
+sbrk (int nbytes)
+{
+  static char *heap = __heap_start;
+  char *base = heap;
+  char *new_heap = heap + nbytes;
+  
+  if (nbytes < 0 || new_heap > __heap_end)
+    {
+      errno = ENOMEM;
+      return (void *)-1;
+    }
+  heap = new_heap;
+  return base;
+}