51   { // subtracting negative values  in main()
53     check("subtract negative value to cause wrap",  in main()
56     check("add negative value to cause wrap",  in main()
86   // adding & subtracting negative values  in main()
89   check("add negative value", (wi7.add(-2) == 0 && wi7 == 4));  in main()
90   check("add negative value", (wi8.add(-2) == 0 && wi8 == -2));  in main()
91   check("add negative value to cause single wrap",   in main()
93   check("add negative value to cause single wrap",   in main()
95   check("add negative value to cause multiple wrap",   in main()
97   check("add negative value to cause multiple wrap",   in main()
104   check("subtract negative value", (wi7.subtract(-2) == 0 && wi7 == 8));  in main()
105   check("subtract negative value", (wi8.subtract(-2) == 0 && wi8 == 2));  in main()
106   check("subtract negative value to cause single wrap",   in main()
108   check("subtract negative value to cause single wrap",   in main()
110   check("subtract negative value to cause multiple wrap",   in main()
112   check("subtract negative value to cause multiple wrap",   in main()