1 files changed, 25 insertions, 0 deletions
diff --git a/src/avr/alloc.c b/src/avr/alloc.c
new file mode 100644
index 000000000..aaa671bc7
--- /dev/null
+++ b/src/avr/alloc.c
@@ -0,0 +1,25 @@
+// AVR allocation checking code.
+//
+// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <avr/io.h> // AVR_STACK_POINTER_REG
+#include <stdlib.h> // __malloc_heap_end
+#include "autoconf.h" // CONFIG_AVR_STACK_SIZE
+#include "compiler.h" // ALIGN
+#include "misc.h" // alloc_maxsize
+
+size_t
+alloc_maxsize(size_t reqsize)
+{
+    uint16_t memend = ALIGN(AVR_STACK_POINTER_REG, 256);
+    __malloc_heap_end = (void*)memend - CONFIG_AVR_STACK_SIZE;
+    extern char *__brkval;
+    int16_t maxsize = __malloc_heap_end - __brkval - 2;
+    if (maxsize < 0)
+        return 0;
+    if (reqsize < maxsize)
+        return reqsize;
+    return maxsize;
+}