1 files changed, 110 insertions, 0 deletions

diff --git a/firmware/libc/memset.c b/firmware/libc/memset.c
new file mode 100644
index 0000000000..7b8d2137e8
--- /dev/null
+++ b/firmware/libc/memset.c
@@ -0,0 +1,110 @@
+/*
+FUNCTION
+        <<memset>>---set an area of memory
+
+INDEX
+        memset
+
+ANSI_SYNOPSIS
+        #include <string.h>
+        void *memset(const void *<[dst]>, int <[c]>, size_t <[length]>);
+
+TRAD_SYNOPSIS
+        #include <string.h>
+        void *memset(<[dst]>, <[c]>, <[length]>)
+        void *<[dst]>;
+        int <[c]>;
+        size_t <[length]>;
+
+DESCRIPTION
+        This function converts the argument <[c]> into an unsigned
+        char and fills the first <[length]> characters of the array
+        pointed to by <[dst]> to the value.
+
+RETURNS
+        <<memset>> returns the value of <[m]>.
+
+PORTABILITY
+<<memset>> is ANSI C.
+
+    <<memset>> requires no supporting OS subroutines.
+
+QUICKREF
+        memset ansi pure
+*/
+
+#include <string.h>
+#include "_ansi.h"
+
+#define LBLOCKSIZE (sizeof(long))
+#define UNALIGNED(X)   ((long)X & (LBLOCKSIZE - 1))
+#define TOO_SMALL(LEN) ((LEN) < LBLOCKSIZE)
+
+_PTR 
+_DEFUN (memset, (m, c, n),
+        _PTR m _AND
+        int c _AND
+        size_t n)
+{
+#if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__)
+  char *s = (char *) m;
+
+  while (n-- != 0)
+    {
+      *s++ = (char) c;
+    }
+
+  return m;
+#else
+  char *s = (char *) m;
+  unsigned int i;
+  unsigned long buffer;
+  unsigned long *aligned_addr;
+
+  if (!TOO_SMALL (n) && !UNALIGNED (m))
+    {
+      /* If we get this far, we know that n is large and m is word-aligned. */
+
+      aligned_addr = (unsigned long*)m;
+
+      /* Store C into each char sized location in BUFFER so that
+         we can set large blocks quickly.  */
+      c &= 0xff;
+      if (LBLOCKSIZE == 4)
+        {
+          buffer = (c << 8) | c;
+          buffer |= (buffer << 16);
+        }
+      else
+        {
+          buffer = 0;
+          for (i = 0; i < LBLOCKSIZE; i++)
+            buffer = (buffer << 8) | c;
+        }
+
+      while (n >= LBLOCKSIZE*4)
+        {
+          *aligned_addr++ = buffer;
+          *aligned_addr++ = buffer;
+          *aligned_addr++ = buffer;
+          *aligned_addr++ = buffer;
+          n -= 4*LBLOCKSIZE;
+        }
+
+      while (n >= LBLOCKSIZE)
+        {
+          *aligned_addr++ = buffer;
+          n -= LBLOCKSIZE;
+        }
+      /* Pick up the remainder with a bytewise loop.  */
+      s = (char*)aligned_addr;
+    }
+
+  while (n--)
+    {
+      *s++ = (char)c;
+    }
+
+  return m;
+#endif /* not PREFER_SIZE_OVER_SPEED */
+}