diff --git a/chip-z80/nodenames.js b/chip-z80/nodenames.js
index f304a4c..42108bd 100644
--- a/chip-z80/nodenames.js
+++ b/chip-z80/nodenames.js
@@ -67,230 +67,230 @@ ex_dehl0: 625,
 ex_dehl1: 629,
 ex_dehl_combined: 626,
 // Registers
-reg_a0: 2271,
-reg_a1: 2296,
-reg_a2: 2384,
-reg_a3: 2416,
-reg_a4: 2489,
-reg_a5: 2527,
-reg_a6: 2610,
-reg_a7: 2633,
-reg_f0: 1854,
-reg_f1: 1881,
-reg_f2: 1958,
-reg_f3: 1986,
-reg_f4: 2058,
-reg_f5: 2082,
-reg_f6: 2155,
-reg_f7: 2179,
-reg_b0: 2268,
-reg_b1: 2293,
-reg_b2: 2381,
-reg_b3: 2413,
-reg_b4: 2486,
-reg_b5: 2524,
-reg_b6: 2607,
-reg_b7: 2630,
-reg_c0: 1851,
-reg_c1: 1878,
-reg_c2: 1955,
-reg_c3: 1983,
-reg_c4: 2055,
-reg_c5: 2079,
-reg_c6: 2152,
-reg_c7: 2176,
-reg_d0: 2264,
-reg_d1: 2289,
-reg_d2: 2377,
-reg_d3: 2409,
-reg_d4: 2482,
-reg_d5: 2520,
-reg_d6: 2603,
-reg_d7: 2626,
-reg_e0: 1847,
-reg_e1: 1874,
-reg_e2: 1951,
-reg_e3: 1979,
-reg_e4: 2051,
-reg_e5: 2075,
-reg_e6: 2148,
-reg_e7: 2172,
-reg_h0: 2266,
-reg_h1: 2291,
-reg_h2: 2379,
-reg_h3: 2411,
-reg_h4: 2484,
-reg_h5: 2522,
-reg_h6: 2605,
-reg_h7: 2628,
-reg_l0: 1849,
-reg_l1: 1876,
-reg_l2: 1953,
-reg_l3: 1981,
-reg_l4: 2053,
-reg_l5: 2077,
-reg_l6: 2150,
-reg_l7: 2174,
-reg_w0: 2260,
-reg_w1: 2285,
-reg_w2: 2373,
-reg_w3: 2405,
-reg_w4: 2478,
-reg_w5: 2516,
-reg_w6: 2599,
-reg_w7: 2622,
-reg_z0: 1843,
-reg_z1: 1870,
-reg_z2: 1947,
-reg_z3: 1975,
-reg_z4: 2047,
-reg_z5: 2071,
-reg_z6: 2144,
-reg_z7: 2168,
-reg_pch0: 2258,
-reg_pch1: 2283,
-reg_pch2: 2371,
-reg_pch3: 2403,
-reg_pch4: 2476,
-reg_pch5: 2514,
-reg_pch6: 2597,
-reg_pch7: 2620,
-reg_pcl0: 1841,
-reg_pcl1: 1868,
-reg_pcl2: 1945,
-reg_pcl3: 1973,
-reg_pcl4: 2045,
-reg_pcl5: 2069,
-reg_pcl6: 2142,
-reg_pcl7: 2166,
-reg_sph0: 2261,
-reg_sph1: 2286,
-reg_sph2: 2374,
-reg_sph3: 2406,
-reg_sph4: 2479,
-reg_sph5: 2517,
-reg_sph6: 2600,
-reg_sph7: 2623,
-reg_spl0: 1844,
-reg_spl1: 1871,
-reg_spl2: 1948,
-reg_spl3: 1976,
-reg_spl4: 2048,
-reg_spl5: 2072,
-reg_spl6: 2145,
-reg_spl7: 2169,
-reg_ixh0: 2263,
-reg_ixh1: 2288,
-reg_ixh2: 2376,
-reg_ixh3: 2408,
-reg_ixh4: 2481,
-reg_ixh5: 2519,
-reg_ixh6: 2602,
-reg_ixh7: 2625,
-reg_ixl0: 1846,
-reg_ixl1: 1873,
-reg_ixl2: 1950,
-reg_ixl3: 1978,
-reg_ixl4: 2050,
-reg_ixl5: 2074,
-reg_ixl6: 2147,
-reg_ixl7: 2171,
-reg_iyh0: 2262,
-reg_iyh1: 2287,
-reg_iyh2: 2375,
-reg_iyh3: 2407,
-reg_iyh4: 2480,
-reg_iyh5: 2518,
-reg_iyh6: 2601,
-reg_iyh7: 2624,
-reg_iyl0: 1845,
-reg_iyl1: 1872,
-reg_iyl2: 1949,
-reg_iyl3: 1977,
-reg_iyl4: 2049,
-reg_iyl5: 2073,
-reg_iyl6: 2146,
-reg_iyl7: 2170,
-reg_i0: 2259,
-reg_i1: 2284,
-reg_i2: 2372,
-reg_i3: 2404,
-reg_i4: 2477,
-reg_i5: 2515,
-reg_i6: 2598,
-reg_i7: 2621,
-reg_r0: 1842,
-reg_r1: 1869,
-reg_r2: 1946,
-reg_r3: 1974,
-reg_r4: 2046,
-reg_r5: 2070,
-reg_r6: 2143,
-reg_r7: 2167,
-reg_aa0: 2270,
-reg_aa1: 2295,
-reg_aa2: 2383,
-reg_aa3: 2415,
-reg_aa4: 2488,
-reg_aa5: 2526,
-reg_aa6: 2609,
-reg_aa7: 2632,
-reg_ff0: 1853,
-reg_ff1: 1880,
-reg_ff2: 1957,
-reg_ff3: 1985,
-reg_ff4: 2057,
-reg_ff5: 2081,
-reg_ff6: 2154,
-reg_ff7: 2178,
-reg_bb0: 2269,
-reg_bb1: 2294,
-reg_bb2: 2382,
-reg_bb3: 2414,
-reg_bb4: 2487,
-reg_bb5: 2525,
-reg_bb6: 2608,
-reg_bb7: 2631,
-reg_cc0: 1852,
-reg_cc1: 1879,
-reg_cc2: 1956,
-reg_cc3: 1984,
-reg_cc4: 2056,
-reg_cc5: 2080,
-reg_cc6: 2153,
-reg_cc7: 2177,
-reg_dd0: 2265,
-reg_dd1: 2290,
-reg_dd2: 2378,
-reg_dd3: 2410,
-reg_dd4: 2483,
-reg_dd5: 2521,
-reg_dd6: 2604,
-reg_dd7: 2627,
-reg_ee0: 1848,
-reg_ee1: 1875,
-reg_ee2: 1952,
-reg_ee3: 1980,
-reg_ee4: 2052,
-reg_ee5: 2076,
-reg_ee6: 2149,
-reg_ee7: 2173,
-reg_hh0: 2267,
-reg_hh1: 2292,
-reg_hh2: 2380,
-reg_hh3: 2412,
-reg_hh4: 2485,
-reg_hh5: 2523,
-reg_hh6: 2606,
-reg_hh7: 2629,
-reg_ll0: 1850,
-reg_ll1: 1877,
-reg_ll2: 1954,
-reg_ll3: 1982,
-reg_ll4: 2054,
-reg_ll5: 2078,
-reg_ll6: 2151,
-reg_ll7: 2175,
+reg_a0: 2245,
+reg_a1: 2319,
+reg_a2: 2357,
+reg_a3: 2442,
+reg_a4: 2463,
+reg_a5: 2552,
+reg_a6: 2586,
+reg_a7: 2656,
+reg_f0: 1827,
+reg_f1: 1903,
+reg_f2: 1928,
+reg_f3: 2009,
+reg_f4: 2032,
+reg_f5: 2107,
+reg_f6: 2132,
+reg_f7: 2209,
+reg_b0: 2242,
+reg_b1: 2316,
+reg_b2: 2354,
+reg_b3: 2439,
+reg_b4: 2460,
+reg_b5: 2549,
+reg_b6: 2583,
+reg_b7: 2653,
+reg_c0: 1824,
+reg_c1: 1900,
+reg_c2: 1925,
+reg_c3: 2006,
+reg_c4: 2029,
+reg_c5: 2104,
+reg_c6: 2129,
+reg_c7: 2206,
+reg_d0: 2238,
+reg_d1: 2312,
+reg_d2: 2350,
+reg_d3: 2435,
+reg_d4: 2456,
+reg_d5: 2545,
+reg_d6: 2579,
+reg_d7: 2649,
+reg_e0: 1820,
+reg_e1: 1896,
+reg_e2: 1921,
+reg_e3: 2002,
+reg_e4: 2025,
+reg_e5: 2100,
+reg_e6: 2125,
+reg_e7: 2202,
+reg_h0: 2240,
+reg_h1: 2314,
+reg_h2: 2352,
+reg_h3: 2437,
+reg_h4: 2458,
+reg_h5: 2547,
+reg_h6: 2581,
+reg_h7: 2651,
+reg_l0: 1822,
+reg_l1: 1898,
+reg_l2: 1923,
+reg_l3: 2004,
+reg_l4: 2027,
+reg_l5: 2102,
+reg_l6: 2127,
+reg_l7: 2204,
+reg_w0: 2234,
+reg_w1: 2308,
+reg_w2: 2346,
+reg_w3: 2431,
+reg_w4: 2452,
+reg_w5: 2541,
+reg_w6: 2575,
+reg_w7: 2645,
+reg_z0: 1816,
+reg_z1: 1892,
+reg_z2: 1917,
+reg_z3: 1998,
+reg_z4: 2021,
+reg_z5: 2096,
+reg_z6: 2121,
+reg_z7: 2198,
+reg_pch0: 2232,
+reg_pch1: 2306,
+reg_pch2: 2344,
+reg_pch3: 2429,
+reg_pch4: 2450,
+reg_pch5: 2539,
+reg_pch6: 2573,
+reg_pch7: 2643,
+reg_pcl0: 1814,
+reg_pcl1: 1890,
+reg_pcl2: 1915,
+reg_pcl3: 1996,
+reg_pcl4: 2019,
+reg_pcl5: 2094,
+reg_pcl6: 2119,
+reg_pcl7: 2196,
+reg_sph0: 2235,
+reg_sph1: 2309,
+reg_sph2: 2347,
+reg_sph3: 2432,
+reg_sph4: 2453,
+reg_sph5: 2542,
+reg_sph6: 2576,
+reg_sph7: 2646,
+reg_spl0: 1817,
+reg_spl1: 1893,
+reg_spl2: 1918,
+reg_spl3: 1999,
+reg_spl4: 2022,
+reg_spl5: 2097,
+reg_spl6: 2122,
+reg_spl7: 2199,
+reg_ixh0: 2237,
+reg_ixh1: 2311,
+reg_ixh2: 2349,
+reg_ixh3: 2434,
+reg_ixh4: 2455,
+reg_ixh5: 2544,
+reg_ixh6: 2578,
+reg_ixh7: 2648,
+reg_ixl0: 1819,
+reg_ixl1: 1895,
+reg_ixl2: 1920,
+reg_ixl3: 2001,
+reg_ixl4: 2024,
+reg_ixl5: 2099,
+reg_ixl6: 2124,
+reg_ixl7: 2201,
+reg_iyh0: 2236,
+reg_iyh1: 2310,
+reg_iyh2: 2348,
+reg_iyh3: 2433,
+reg_iyh4: 2454,
+reg_iyh5: 2543,
+reg_iyh6: 2577,
+reg_iyh7: 2647,
+reg_iyl0: 1818,
+reg_iyl1: 1894,
+reg_iyl2: 1919,
+reg_iyl3: 2000,
+reg_iyl4: 2023,
+reg_iyl5: 2098,
+reg_iyl6: 2123,
+reg_iyl7: 2200,
+reg_i0: 2233,
+reg_i1: 2307,
+reg_i2: 2345,
+reg_i3: 2430,
+reg_i4: 2451,
+reg_i5: 2540,
+reg_i6: 2574,
+reg_i7: 2644,
+reg_r0: 1815,
+reg_r1: 1891,
+reg_r2: 1916,
+reg_r3: 1997,
+reg_r4: 2020,
+reg_r5: 2095,
+reg_r6: 2120,
+reg_r7: 2197,
+reg_aa0: 2244,
+reg_aa1: 2318,
+reg_aa2: 2356,
+reg_aa3: 2441,
+reg_aa4: 2462,
+reg_aa5: 2551,
+reg_aa6: 2585,
+reg_aa7: 2655,
+reg_ff0: 1826,
+reg_ff1: 1902,
+reg_ff2: 1927,
+reg_ff3: 2008,
+reg_ff4: 2031,
+reg_ff5: 2106,
+reg_ff6: 2131,
+reg_ff7: 2208,
+reg_bb0: 2243,
+reg_bb1: 2317,
+reg_bb2: 2355,
+reg_bb3: 2440,
+reg_bb4: 2461,
+reg_bb5: 2550,
+reg_bb6: 2584,
+reg_bb7: 2654,
+reg_cc0: 1825,
+reg_cc1: 1901,
+reg_cc2: 1926,
+reg_cc3: 2007,
+reg_cc4: 2030,
+reg_cc5: 2105,
+reg_cc6: 2130,
+reg_cc7: 2207,
+reg_dd0: 2239,
+reg_dd1: 2313,
+reg_dd2: 2351,
+reg_dd3: 2436,
+reg_dd4: 2457,
+reg_dd5: 2546,
+reg_dd6: 2580,
+reg_dd7: 2650,
+reg_ee0: 1821,
+reg_ee1: 1897,
+reg_ee2: 1922,
+reg_ee3: 2003,
+reg_ee4: 2026,
+reg_ee5: 2101,
+reg_ee6: 2126,
+reg_ee7: 2203,
+reg_hh0: 2241,
+reg_hh1: 2315,
+reg_hh2: 2353,
+reg_hh3: 2438,
+reg_hh4: 2459,
+reg_hh5: 2548,
+reg_hh6: 2582,
+reg_hh7: 2652,
+reg_ll0: 1823,
+reg_ll1: 1899,
+reg_ll2: 1924,
+reg_ll3: 2005,
+reg_ll4: 2028,
+reg_ll5: 2103,
+reg_ll6: 2128,
+reg_ll7: 2205,
 // Data buses and control
 dp_dl: 82,
 dl_dp: 165,
diff --git a/chip-z80/support.js b/chip-z80/support.js
index b9167c6..3f794ad 100644
--- a/chip-z80/support.js
+++ b/chip-z80/support.js
@@ -260,48 +260,48 @@ function handleBusWrite(){
 
 function readA() {
     if (!isNodeHigh(nodenames['ex_af'])) {
-        return 0xFF ^ readBits('reg_aa', 8);
+        return readBits('reg_aa', 8);
     } else {
-        return 0xFF ^ readBits('reg_a', 8);
+        return readBits('reg_a', 8);
     }
 }
 
 function readF() {
     if (!isNodeHigh(nodenames['ex_af'])) {
-        return 0xFF ^ readBits('reg_ff', 8);
+        return readBits('reg_ff', 8);
     } else {
-        return 0xFF ^ readBits('reg_f', 8);
+        return readBits('reg_f', 8);
     }
 }
 
 function readB() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
-        return 0xFF ^ readBits('reg_bb', 8);
+        return readBits('reg_bb', 8);
     } else {
-        return 0xFF ^ readBits('reg_b', 8);
+        return readBits('reg_b', 8);
     }
 }
 
 function readC() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
-        return 0xFF ^ readBits('reg_cc', 8);
+        return readBits('reg_cc', 8);
     } else {
-        return 0xFF ^ readBits('reg_c', 8);
+        return readBits('reg_c', 8);
     }
 }
 
 function readD() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_hh', 8);
+            return readBits('reg_hh', 8);
         } else {
-            return 0xFF ^ readBits('reg_dd', 8);
+            return readBits('reg_dd', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_h', 8);
+            return readBits('reg_h', 8);
         } else {
-            return 0xFF ^ readBits('reg_d', 8);
+            return readBits('reg_d', 8);
         }
     }
 }
@@ -309,15 +309,15 @@ function readD() {
 function readE() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_ll', 8);
+            return readBits('reg_ll', 8);
         } else {
-            return 0xFF ^ readBits('reg_ee', 8);
+            return readBits('reg_ee', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_l', 8);
+            return readBits('reg_l', 8);
         } else {
-            return 0xFF ^ readBits('reg_e', 8);
+            return readBits('reg_e', 8);
         }
     }
 }
@@ -325,15 +325,15 @@ function readE() {
 function readH() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_dd', 8);
+            return readBits('reg_dd', 8);
         } else {
-            return 0xFF ^ readBits('reg_hh', 8);
+            return readBits('reg_hh', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_d', 8);
+            return readBits('reg_d', 8);
         } else {
-            return 0xFF ^ readBits('reg_h', 8);
+            return readBits('reg_h', 8);
         }
     }
 }
@@ -341,63 +341,63 @@ function readH() {
 function readL() {
     if (isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_ee', 8);
+            return readBits('reg_ee', 8);
         } else {
-            return 0xFF ^ readBits('reg_ll', 8);
+            return readBits('reg_ll', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_e', 8);
+            return readBits('reg_e', 8);
         } else {
-            return 0xFF ^ readBits('reg_l', 8);
+            return readBits('reg_l', 8);
         }
     }
 }
 
 function readA2() {
     if (isNodeHigh(nodenames['ex_af'])) {
-        return 0xFF ^ readBits('reg_aa', 8);
+        return readBits('reg_aa', 8);
     } else {
-        return 0xFF ^ readBits('reg_a', 8);
+        return readBits('reg_a', 8);
     }
 }
 
 function readF2() {
     if (isNodeHigh(nodenames['ex_af'])) {
-        return 0xFF ^ readBits('reg_ff', 8);
+        return readBits('reg_ff', 8);
     } else {
-        return 0xFF ^ readBits('reg_f', 8);
+        return readBits('reg_f', 8);
     }
 }
 
 function readB2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
-        return 0xFF ^ readBits('reg_bb', 8);
+        return readBits('reg_bb', 8);
     } else {
-        return 0xFF ^ readBits('reg_b', 8);
+        return readBits('reg_b', 8);
     }
 }
 
 function readC2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
-        return 0xFF ^ readBits('reg_cc', 8);
+        return readBits('reg_cc', 8);
     } else {
-        return 0xFF ^ readBits('reg_c', 8);
+        return readBits('reg_c', 8);
     }
 }
 
 function readD2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_hh', 8);
+            return readBits('reg_hh', 8);
         } else {
-            return 0xFF ^ readBits('reg_dd', 8);
+            return readBits('reg_dd', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_h', 8);
+            return readBits('reg_h', 8);
         } else {
-            return 0xFF ^ readBits('reg_d', 8);
+            return readBits('reg_d', 8);
         }
     }
 }
@@ -405,15 +405,15 @@ function readD2() {
 function readE2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_ll', 8);
+            return readBits('reg_ll', 8);
         } else {
-            return 0xFF ^ readBits('reg_ee', 8);
+            return readBits('reg_ee', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_l', 8);
+            return readBits('reg_l', 8);
         } else {
-            return 0xFF ^ readBits('reg_e', 8);
+            return readBits('reg_e', 8);
         }
     }
 }
@@ -421,15 +421,15 @@ function readE2() {
 function readH2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_dd', 8);
+            return readBits('reg_dd', 8);
         } else {
-            return 0xFF ^ readBits('reg_hh', 8);
+            return readBits('reg_hh', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_d', 8);
+            return readBits('reg_d', 8);
         } else {
-            return 0xFF ^ readBits('reg_h', 8);
+            return readBits('reg_h', 8);
         }
     }
 }
@@ -437,30 +437,30 @@ function readH2() {
 function readL2() {
     if (!isNodeHigh(nodenames['ex_bcdehl'])) {
         if (isNodeHigh(nodenames['ex_dehl1'])) {
-            return 0xFF ^ readBits('reg_ee', 8);
+            return readBits('reg_ee', 8);
         } else {
-            return 0xFF ^ readBits('reg_ll', 8);
+            return readBits('reg_ll', 8);
         }
     } else {
         if (isNodeHigh(nodenames['ex_dehl0'])) {
-            return 0xFF ^ readBits('reg_e', 8);
+            return readBits('reg_e', 8);
         } else {
-            return 0xFF ^ readBits('reg_l', 8);
+            return readBits('reg_l', 8);
         }
     }
 }
 
-function readI(){return 0xFF ^ readBits('reg_i', 8);}
-function readR(){return 0xFF ^ readBits('reg_r', 8);}
-function readW(){return 0xFF ^ readBits('reg_w', 8);}
-function readZ(){return 0xFF ^ readBits('reg_z', 8);}
+function readI(){return readBits('reg_i', 8);}
+function readR(){return readBits('reg_r', 8);}
+function readW(){return readBits('reg_w', 8);}
+function readZ(){return readBits('reg_z', 8);}
 
-function readIX(){return 0xFFFF ^ ((readBits('reg_ixh', 8)<<8) + readBits('reg_ixl', 8));}
-function readIY(){return 0xFFFF ^ ((readBits('reg_iyh', 8)<<8) + readBits('reg_iyl', 8));}
-function readSP(){return 0xFFFF ^ ((readBits('reg_sph', 8)<<8) + readBits('reg_spl', 8));}
-function readPC(){return 0xFFFF ^ ((readBits('reg_pch', 8)<<8) + readBits('reg_pcl', 8));}
-function readPCL(){return 0xFF ^ readBits('reg_pcl', 8);}
-function readPCH(){return 0xFF ^ readBits('reg_pch', 8);}
+function readIX(){return (readBits('reg_ixh', 8)<<8) + readBits('reg_ixl', 8);}
+function readIY(){return (readBits('reg_iyh', 8)<<8) + readBits('reg_iyl', 8);}
+function readSP(){return (readBits('reg_sph', 8)<<8) + readBits('reg_spl', 8);}
+function readPC(){return (readBits('reg_pch', 8)<<8) + readBits('reg_pcl', 8);}
+function readPCL(){return readBits('reg_pcl', 8);}
+function readPCH(){return readBits('reg_pch', 8);}
 
 function formatFstring(f){
     var result;
@@ -492,14 +492,6 @@ function listActiveTCStates() {
     return s.join(" ");
 }
 
-function busToHexInv(busname){
-    var value=busToHex(busname)
-    if (typeof value != "undefined")
-        return value.replace(/./g,function(x){return (15-parseInt(x,16)).toString(16)});
-    else
-        return undefined;;
-}
-
 function busToString(busname){
     // takes a signal name or prefix
     // returns an appropriate string representation
@@ -527,17 +519,17 @@ function busToString(busname){
     if(busname=='hl2')
         return hexByte(readH2()) + hexByte(readL2());
     if(busname=='ir')
-        return busToHexInv('reg_i') + busToHexInv('reg_r');
+        return busToHex('reg_i') + busToHex('reg_r');
     if(busname=='wz')
-        return busToHexInv('reg_w') + busToHexInv('reg_z');
+        return busToHex('reg_w') + busToHex('reg_z');
     if(busname=='pc')
-        return busToHexInv('reg_pch') + busToHexInv('reg_pcl');
+        return busToHex('reg_pch') + busToHex('reg_pcl');
     if(busname=='sp')
-        return busToHexInv('reg_sph') + busToHexInv('reg_spl');
+        return busToHex('reg_sph') + busToHex('reg_spl');
     if(busname=='ix')
-        return busToHexInv('reg_ixh') + busToHexInv('reg_ixl');
+        return busToHex('reg_ixh') + busToHex('reg_ixl');
     if(busname=='iy')
-        return busToHexInv('reg_iyh') + busToHexInv('reg_iyl');
+        return busToHex('reg_iyh') + busToHex('reg_iyl');
     if(busname=='State')
         return listActiveTCStates();
     // DMB: TODO