diff --git a/core/bus.c b/core/bus.c
index 4dd9fd3..1017613 100644
--- a/core/bus.c
+++ b/core/bus.c
@@ -89,7 +89,7 @@ static int32_t busReadMisc(VB *sim, uint8_t address, int type) {
     /* Unmapped */
     switch (type) {
         case VB_S8 : case VB_U8 : if (address & 3) return 0; break;
-        case VB_S16: case VB_U16: if (address & 1) return 0;
+        case VB_S16: case VB_U16: if (address & 2) return 0;
     }
 
     /* Access by register */
@@ -117,7 +117,7 @@ static void busWriteMisc(VB *sim, uint8_t address, int type, int32_t value) {
     /* Unmapped */
     switch (type) {
         case VB_S8 : case VB_U8 : if (address & 3) return; break;
-        case VB_S16: case VB_U16: if (address & 1) return;
+        case VB_S16: case VB_U16: if (address & 2) return;
     }
 
     /* Access by register */
diff --git a/core/cpu.c b/core/cpu.c
index b453536..fcdb3c0 100644
--- a/core/cpu.c
+++ b/core/cpu.c
@@ -1831,7 +1831,7 @@ static uint32_t cpuUntil(VB *sim, uint32_t clocks) {
         return
             sim->cpu.operation == CPU_HALTING                      &&
             !(sim->cpu.psw.id | sim->cpu.psw.ep | sim->cpu.psw.np) &&
-            IRQ_LEVELS[sim->cpu.irq] < sim->cpu.psw.i
+            IRQ_LEVELS[sim->cpu.irq] >= sim->cpu.psw.i
         ? 0 : clocks;
     }
 
diff --git a/core/vb.c b/core/vb.c
index 19c6e9f..1a0221a 100644
--- a/core/vb.c
+++ b/core/vb.c
@@ -103,8 +103,8 @@ struct VB {
         uint8_t  soft_ck;   /* Controller communication signal */
 
         /* Simulation state */
-        uint8_t keys; /* Next input bits */
-        int     step; /* Software read processing phase */
+        uint16_t keys; /* Next input bits */
+        int      step; /* Software read processing phase */
     } pad;
 
     /* Timer */
diff --git a/core/vip.c b/core/vip.c
index d8aa347..962a1a6 100644
--- a/core/vip.c
+++ b/core/vip.c
@@ -606,7 +606,7 @@ static void vipDrawObjects(VB *sim, int group) {
     start = group == 0 ? 0 : (sim->vip.spt[group - 1] + 1) & 1023;
     stop  = sim->vip.spt[group];
     top   = (int32_t) sim->vip.xp.sbcount << 3;
-    for (o = stop;; o = (o - 1) & 1023) {
+    for (o = stop; o != -1; o = o == start ? -1 : (o - 1) & 1023) {
         obj = &sim->vip.ram[0x3E000 | o << 3];
 
         /* Validate object is enabled */
@@ -655,15 +655,12 @@ static void vipDrawObjects(VB *sim, int group) {
                     pixel = src[sy << 1 | sx >> 2] >> ((sx & 3) << 1) & 3;
                     if (pixel != 0)
                         dest[y] = plt[pixel]; /* TODO: Research clocks */
-                } /* x */
+                } /* y */
 
-            } /* y */
+            } /* x */
 
         } /* i */
 
-        /* All objects have been drawn */
-        if (o == start)
-            break;
     }
 
 }
@@ -792,13 +789,12 @@ static void vipDrawWorld(VB *sim, uint8_t *world, uint16_t attr) {
                     param += 4;
                     break;
                 case 2: /* Affine */
-                    dx =  (int32_t) (int16_t) vipParam(param | 6) << 7;
-                    dy =  (int32_t) (int16_t) vipParam(param | 8) << 7;
-                    mp =  (int32_t) (int16_t) vipParam(param | 2);
-                    mx = ((int32_t) (int16_t) vipParam(param    ) << 13) +
-                        dx * (left - ((mp < 0) ^ i ? mp : 0));
-                    my = ((int32_t) (int16_t) vipParam(param | 4) << 13) +
-                        dy * (left - ((mp < 0) ^ i ? mp : 0));
+                    dx =  (int32_t) (int16_t) vipParam(param|6) << 7;
+                    dy =  (int32_t) (int16_t) vipParam(param|8) << 7;
+                    mp =  (int32_t) (int16_t) vipParam(param|2);
+                    mp = left - wx - ((mp < 0) ^ i ? mp : 0);
+                    mx = ((int32_t) (int16_t) vipParam(param  ) << 13) + dx*mp;
+                    my = ((int32_t) (int16_t) vipParam(param|4) << 13) + dy*mp;
                     param += 16;
             }
 
@@ -882,7 +878,7 @@ static void vipRender(VB *sim) {
         attr = busReadBuffer(world, VB_U16);
 
         /* Non-graphical world */
-        if (attr & 0x0020) /* END */
+        if (attr & 0x0040) /* END */
             break;    /* Control world */
         if ((attr & 0xC000) == 0) /* LON, RON */
             continue; /* Dummy world */