--- trunk/doc/exact_match.txt	2004/04/04 20:48:56	299
+++ trunk/doc/exact_match.txt	2004/04/04 21:04:47	300
@@ -30,18 +30,22 @@
 
 What are bit-masks?
 
-Bit-mask is usage of one byte (8 bits) as 8 separate bits with it's own meaning.
-So, 1 = 2^1, thus it's bit 1. So, for 1-3 we have:
+Bit-mask is usage of one byte (8 bits) as 8 separate bits with it's own
+meaning (this is simplification, but bear with me for now).
+
+So, 1 = 2^0, thus it's bit 1. With analogy, 2=2^1 and 3=2^0+2^1. 
+So, for 1-3 we use two bits and have:
 
 number	bits
-1	01
-2	10
-3	11
+1	01	(just begin bit set)
+2	10	(just end bit set)
+3	11	(begin and end bit set)
 
-For that we are using two bits. If we want to produce wild-card match, we use
-bit 3 (2^3 = 4) so we have:
+Thus, with two bits (and values 1-3) we can express should we exact match from
+beginning, end or both. For wild-card match, we use additional bit 3 (2^3 = 4)
+so we have:
 
-number	bits
+number	bits	exact match
 1	001	begin
 2	010	end
 3	011	begin+end
@@ -49,3 +53,4 @@
 5	101	(4+1) begin+wild-card
 6	110	(4+2) end+wild-card
 7	111	(4+3) begin+end+wild-card
+