1 files changed, 47 insertions, 0 deletions
diff --git a/mdk-stage1/dietlibc/lib/strlen.c b/mdk-stage1/dietlibc/lib/strlen.c
new file mode 100644
index 000000000..56c085dac
--- /dev/null
+++ b/mdk-stage1/dietlibc/lib/strlen.c
@@ -0,0 +1,47 @@
+#include <endian.h>
+#include "dietfeatures.h"
+#include <string.h>
+
+#ifdef WANT_SMALL_STRING_ROUTINES
+size_t strlen(const char *s) {
+  register int i;
+  if (!s) return 0;
+  for (i=0; *s; ++s) ++i;
+  return i;
+}
+#else
+static const unsigned long magic = 0x01010101;
+
+size_t strlen(const char *s)
+{
+  const char *t = s;
+  unsigned long word;
+
+  if (!s) return 0;
+
+  /* Byte compare up until word boundary */
+  for (; ((unsigned long) t & 3); t++)
+    if (!*t) return t - s;
+
+  /* Word compare */
+  do {
+    word = *((unsigned long *) t); t += 4;
+    word = (word - magic) &~ word;
+    word &= (magic << 7);
+  } while (word == 0);
+
+#if BYTE_ORDER == LITTLE_ENDIAN
+  /* word & 0x80808080 == word */
+  word = (word - 1) & (magic << 10);
+  word += (word << 8) + (word << 16);
+  t += word >> 26;
+#else
+  if ((word & 0x80800000) == 0) {
+    word <<= 16;
+    t += 2;
+  }
+  if ((word & 0x80000000) == 0) t += 1;
+#endif
+  return ((const char *) t) - 4 - s;
+}
+#endif