compiled newlib, need to hook up the system calls

rocklibc/src/_PDCLIB/_PDCLIB_bigint_digit_log2.c

@@ -0,0 +1,83 @@
+/* _PDCLIB_bigint_digit_log2( bigint_t const * )
+
+   This file is part of the Public Domain C Library (PDCLib).
+   Permission is granted to use, modify, and / or redistribute at will.
+*/
+
+#ifndef REGTEST
+
+#include "pdclib/_PDCLIB_print.h"
+
+#include <stdio.h>
+
+int _PDCLIB_bigint_digit_log2( _PDCLIB_bigint_digit_t digit )
+{
+    unsigned char log2_lookup[] =
+    {
+        0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+        4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
+        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
+    };
+    _PDCLIB_bigint_digit_t t;
+
+#if _PDCLIB_BIGINT_DIGIT_BITS > 16
+    if ( ( t = ( digit >> 24 ) ) )
+    {
+        return log2_lookup[ t ] + 24;
+    }
+    else if ( ( t = ( digit >> 16 ) ) )
+    {
+        return log2_lookup[ t ] + 16;
+    }
+    else
+#endif
+    if ( ( t = ( digit >> 8 ) ) )
+    {
+        return log2_lookup[ t ] + 8;
+    }
+    else if ( digit > 0 )
+    {
+        return log2_lookup[ digit ];
+    }
+    else
+    {
+        return -1;
+    }
+}
+
+#endif
+
+#ifdef TEST
+
+#include "_PDCLIB_test.h"
+
+#include <math.h>
+
+int main( void )
+{
+#ifndef REGTEST
+    unsigned i;
+
+    for ( i = 1; i < (1 << _PDCLIB_BIGINT_DIGIT_BITS); ++i )
+    {
+        //TESTCASE( _PDCLIB_bigint_digit_log2( i ) == (int)log2( i ) );
+    }
+#endif
+
+    return TEST_RESULTS;
+}
+
+#endif