diff --git a/lisp/documentation.lisp b/lisp/documentation.lisp
index 7c20cf0..22bd9e7 100644
--- a/lisp/documentation.lisp
+++ b/lisp/documentation.lisp
@@ -1,4 +1,9 @@
-(set! documentation (lambda (name)
-    (:documentation  (meta name))))
+(set! documentation (lambda (object)
+    (cond ((= (type object) "LMDA") 
+            (let (d (nth 3 (source object)))
+                (cond ((string? d) d)
+                    (t (source object)))))
+        ((member (type object) '("FUNC" "SPFM"))
+            (:documentation (meta object))))))
 
 (set! doc documentation)
diff --git a/lisp/greaterp.lisp b/lisp/greaterp.lisp
index 04a48f9..2122ccd 100644
--- a/lisp/greaterp.lisp
+++ b/lisp/greaterp.lisp
@@ -1,3 +1,3 @@
 (set! > (lambda (a b)
-
-)
\ No newline at end of file
+    "`(> a b)`: Return `t` if `a` is a number greater than `b`, else `nil`."
+    (not (negative? (- a b)))))
\ No newline at end of file
diff --git a/lisp/member.lisp b/lisp/member.lisp
index 71f5dcf..4fc29cd 100644
--- a/lisp/member.lisp
+++ b/lisp/member.lisp
@@ -1,3 +1,5 @@
+(set! nil? (lambda (o) (= o nil)))
+
 (set! member (lambda
             (item collection)
             "Return `t` if this `item` is a member of this `collection`, else `nil`."
diff --git a/src/arith/integer.c b/src/arith/integer.c
index 687ff3c..1884a00 100644
--- a/src/arith/integer.c
+++ b/src/arith/integer.c
@@ -257,9 +257,9 @@ struct cons_pointer add_integers( struct cons_pointer a,
             debug_print_128bit( rv, DEBUG_ARITH );
             debug_print( L"\n", DEBUG_ARITH );
 
-            if ( carry == 0 && ( rv >= 0 || rv < SMALL_INT_LIMIT ) ) {
+            if ( carry == 0 && rv >= 0 && rv < SMALL_INT_LIMIT ) { 
                 result =
-                    acquire_integer( ( int64_t ) ( rv & 0xffffffff ), NIL );
+                    acquire_integer( ( int64_t ) ( rv & MAX_INTEGER ), NIL ); 
                 break;
             } else {
                 struct cons_pointer new = make_integer( 0, NIL );
diff --git a/unit-tests/subtract.sh b/unit-tests/subtract.sh
new file mode 100644
index 0000000..2c2e601
--- /dev/null
+++ b/unit-tests/subtract.sh
@@ -0,0 +1,190 @@
+#!/bin/bash
+
+# Tests for smallnum subtraction
+
+result=0
+
+
+echo -n "$0: (- 5 4)... "
+
+expected="1"
+actual=`echo "(- 5 4)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 5.0 4)... "
+
+expected="1"
+actual=`echo "(- 5.0 4)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 5 4.0)... "
+
+expected="1"
+actual=`echo "(- 5 4.0)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 5.01 4.0)... "
+
+expected="1.0100000000000000002082"
+actual=`echo "(- 5.01 4.0)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 5 4/5)... "
+
+expected="24/5"
+actual=`echo "(- 5 4/5)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: max smallint (- 1152921504606846975 1)... "
+
+expected="1,152,921,504,606,846,974"
+actual=`echo "(- 1152921504606846975 1)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: max smallint (- 1152921504606846975 1152921504606846974)... "
+
+expected="1"
+actual=`echo "(- 1152921504606846975 1152921504606846974)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 4 5)... "
+
+expected="-1"
+actual=`echo "(- 4 5)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 4 5.0)... "
+
+expected="-1"
+actual=`echo "(- 4 5.0)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 4.0 5)... "
+
+expected="-1"
+actual=`echo "(- 4.0 5)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 4.0 5.01)... "
+
+expected="-1.0100000000000000002082"
+actual=`echo "(- 4.0 5.01)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: (- 4/5 5)... "
+
+expected="-3/5"
+actual=`echo "(- 4/5 5)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: max smallint (- 1 1152921504606846975)... "
+
+expected="-1,152,921,504,606,846,974"
+actual=`echo "(- 1 1152921504606846975)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+echo -n "$0: max smallint (- 1152921504606846974 1152921504606846975)... "
+
+expected="-1"
+actual=`echo "(- 1152921504606846974 1152921504606846975)" | target/psse 2>/dev/null | tail -1`
+
+if [ "${expected}" = "${actual}" ]
+then
+    echo "OK"
+else
+    echo "Fail: expected '${expected}', got '${actual}'"
+    result=`echo "${result} + 1" | bc`
+fi
+
+exit ${result}