Add libmp.
diff --git a/src/libmp/port/letomp.c b/src/libmp/port/letomp.c
new file mode 100644
index 0000000..e23fed2
--- /dev/null
+++ b/src/libmp/port/letomp.c
@@ -0,0 +1,28 @@
+#include "os.h"
+#include <mp.h>
+#include "dat.h"
+
+// convert a little endian byte array (least significant byte first) to an mpint
+mpint*
+letomp(uchar *s, uint n, mpint *b)
+{
+ int i=0, m = 0;
+ mpdigit x=0;
+
+ if(b == nil)
+ b = mpnew(0);
+ mpbits(b, 8*n);
+ for(; n > 0; n--){
+ x |= ((mpdigit)(*s++)) << i;
+ i += 8;
+ if(i == Dbits){
+ b->p[m++] = x;
+ i = 0;
+ x = 0;
+ }
+ }
+ if(i > 0)
+ b->p[m++] = x;
+ b->top = m;
+ return b;
+}
