forgot to add this file before

diff --git a/vhdl/code/mathhelpers.vhd b/vhdl/code/mathhelpers.vhd
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+library work;
+
+package mathhelpers is
+--- find minimum number of bits required to
+--- represent N as an unsigned binary number
+---
+function log2_ceil(N: natural) return integer;
+function plus_one_log2_ceil(N: natural) return positive;
+end;
+
+package body mathhelpers is
+--- Calculate the rounded up logarithm dualis (binary logarithm) CEIL(log2(N))
+--- represent N as an unsigned binary number
+---
+function log2_ceil(N: natural) return integer is
+begin
+if N = 1 then
+  return 0;
+elsif N  < 3 then
+return 1;
+else
+return 1 + log2_ceil((N-1)/2+1);
+end if;
+end;
+
+
+--- from http://www.velocityreviews.com/forums/t22799-log2-n.html:
+--- find minimum number of bits required to
+--- represent N as an unsigned binary number
+---
+function plus_one_log2_ceil(N: natural) return positive is
+begin
+if N < 2 then
+return 1;
+else
+return 1 + plus_one_log2_ceil(N/2);
+end if;
+end;
+
+end;