initial

system/src/newlib/_sbrk.c

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+//
+// This file is part of the µOS++ III distribution.
+// Copyright (c) 2014 Liviu Ionescu.
+//
+
+// ----------------------------------------------------------------------------
+
+#include <sys/types.h>
+#include <errno.h>
+
+// ----------------------------------------------------------------------------
+
+caddr_t
+_sbrk(int incr);
+
+// ----------------------------------------------------------------------------
+
+// The definitions used here should be kept in sync with the
+// stack definitions in the linker script.
+
+caddr_t
+_sbrk(int incr)
+{
+  extern char _Heap_Begin; // Defined by the linker.
+  extern char _Heap_Limit; // Defined by the linker.
+
+  static char* current_heap_end;
+  char* current_block_address;
+
+  if (current_heap_end == 0)
+    {
+      current_heap_end = &_Heap_Begin;
+    }
+
+  current_block_address = current_heap_end;
+
+  // Need to align heap to word boundary, else will get
+  // hard faults on Cortex-M0. So we assume that heap starts on
+  // word boundary, hence make sure we always add a multiple of
+  // 4 to it.
+  incr = (incr + 3) & (~3); // align value to 4
+  if (current_heap_end + incr > &_Heap_Limit)
+    {
+      // Some of the libstdc++-v3 tests rely upon detecting
+      // out of memory errors, so do not abort here.
+#if 0
+      extern void abort (void);
+
+      _write (1, "_sbrk: Heap and stack collision\n", 32);
+
+      abort ();
+#else
+      // Heap has overflowed
+      errno = ENOMEM;
+      return (caddr_t) - 1;
+#endif
+    }
+
+  current_heap_end += incr;
+
+  return (caddr_t) current_block_address;
+}
+
+// ----------------------------------------------------------------------------
+