Initial data commit

Task/Ethiopian-multiplication/UNIX-Shell/ethiopian-multiplication-1.sh

@@ -0,0 +1,30 @@
+halve()
+{
+    expr "$1" / 2
+}
+
+double()
+{
+    expr "$1" \* 2
+}
+
+is_even()
+{
+    expr "$1" % 2 = 0 >/dev/null
+}
+
+ethiopicmult()
+{
+    plier=$1
+    plicand=$2
+    r=0
+    while [ "$plier" -ge 1 ]; do
+	is_even "$plier" || r=`expr $r + "$plicand"`
+	plier=`halve "$plier"`
+	plicand=`double "$plicand"`
+    done
+    echo $r
+}
+
+ethiopicmult 17 34
+# => 578

Task/Ethiopian-multiplication/UNIX-Shell/ethiopian-multiplication-2.sh

@@ -0,0 +1,28 @@
+halve() {
+  (( $1 >>= 1 ))
+}
+
+double() {
+  (( $1 <<= 1 ))
+}
+
+is_even() {
+  (( ($1 & 1) == 0 ))
+}
+
+multiply() {
+  local plier=$1
+  local plicand=$2
+  local result=0
+
+  while (( plier > 0 ))
+  do
+    is_even plier || (( result += plicand ))
+    halve plier
+    double plicand
+  done
+  echo $result
+}
+
+multiply 17 34
+# => 578