Bignum subtraction does NOT work

Also subtraction of large numbers which are not beyond the bignum barrier does not work.

unit-tests/bignum-subtract.sh

@@ -0,0 +1,116 @@
+#!/bin/bash
+
+#####################################################################
+# subtract a smallnum from a smallnum to produce a smallnum
+# (right on the boundary)
+a=1152921504606846976
+b=1
+expected='1152921504606846975'
+output=`echo "(- $a $b)" | target/psse -v 2 2>psse.log`
+
+actual=`echo $output |\
+  tail -1 |\
+  sed 's/\,//g'`
+
+echo -n "subtracting $b from $a: "
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi
+
+echo -n "checking no bignum was created: "
+grep -v 'BIGNUM!' psse.log > /dev/null
+if [ $? -eq "0" ]
+then
+    echo "OK"
+else
+    echo "Fail"
+    exit 1
+fi
+
+#####################################################################
+# subtract a smallnum from a bignum to produce a smallnum
+# (just over the boundary)
+a='1152921504606846977'
+b=1
+expected='1152921504606846976'
+output=`echo "(- $a $b)" | target/psse -v 2 2>psse.log`
+
+actual=`echo $output |\
+  tail -1 |\
+  sed 's/\,//g'`
+
+echo -n "subtracting $b from $a: "
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi
+
+#####################################################################
+# subtract a smallnum from a bignum to produce a smallnum
+a='1152921504606846978'
+b=1
+expected='1152921504606846977'
+output=`echo "(- $a $b)" | target/psse -v 2 2>psse.log`
+
+actual=`echo $output |\
+  tail -1 |\
+  sed 's/\,//g'`
+
+echo -n "subtracting $b from $a: "
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi
+
+
+#####################################################################
+# subtract a bignum  from a smallnum to produce a negstive smallnum
+# (just over the boundary)
+a=1
+b=1152921504606846977
+expected='-1152921504606846976'
+output=`echo "(- $a $b)" | target/psse -v 2 2>psse.log`
+
+actual=`echo $output |\
+  tail -1 |\
+  sed 's/\,//g'`
+
+echo -n "subtracting $b from $a: "
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi
+
+#####################################################################
+# subtract a bignum from a bignum to produce a bignum
+a=20000000000000000000
+b=10000000000000000000
+expected=10000000000000000000
+output=`echo "(- $a $b)" | target/psse -v 2 2>psse.log`
+
+actual=`echo $output |\
+  tail -1 |\
+  sed 's/\,//g'`
+
+echo -n "subtracting $b from $a: "
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    exit 1
+fi
+