added sys.time, sys.random, sys.srandom.

removed test-bi.sh
wrote a simple bigint test program into test-bi.hcl

t/test-bi.hcl

@@ -0,0 +1,36 @@
+## test big integer operations
+## hcl --log /dev/null,warn+ test-bi.hcl
+
+(sys.srandom (sys.time))
+(set count 0)
+(while true
+	(printf "%O\r" count)
+	(set count (+ count 1))
+
+	(set limit (rem (sys.random) 30))
+	(set dividend (sys.random))
+	(set i 1)
+	(while (< i limit)
+		(set dividend (bit-or (bit-shift dividend 30) (sys.random)))
+		(set i (+ i 1))
+	)
+
+	(set limit (rem (sys.random) 30))
+	(set divisor (sys.random))
+	(set i 1)
+	(while (< i limit)
+		(set divisor (bit-or (bit-shift divisor 30) (sys.random)))
+		(set i (+ i 1))
+	)
+
+	(set quotient (/ dividend divisor))
+	(set remainder (rem dividend divisor))
+	(set derived_dividend (+ (* quotient divisor) remainder))
+
+	(if (/= dividend derived_dividend)
+		(printf ">> dividend %O\n>> divisor %O\n>> quotient %O\n>> remainder %O\n>> derived_dividend %O\n"
+			dividend divisor quotient remainder derived_dividend)
+		(break)
+	)
+)
+(printf "\n")