diff --git a/core/vb.c b/core/vb.c
index 165a1af..fb34d83 100644
--- a/core/vb.c
+++ b/core/vb.c
@@ -121,6 +121,7 @@ struct VB {
             uint32_t fbSrc;   /* Source frame buffer address */
             int32_t  repeat;  /* Current column table repeat value */
             int      step;    /* Processing phase */
+            uint32_t until;   /* Clocks until interrupt condition */
         } dp;
 
         /* Pixel processor */
diff --git a/core/vip.c b/core/vip.c
index 2d3f319..b97201c 100644
--- a/core/vip.c
+++ b/core/vip.c
@@ -382,16 +382,18 @@ static int vipOnFrame(VB *sim) {
 static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
 
     /* Process all clocks */
-    while (clocks != 0) {
+    for (;;) {
 
         /* The next event is after the time remaining */
         if (sim->vip.dp.clocks > clocks) {
             sim->vip.dp.clocks -= clocks;
+            sim->vip.dp.until  -= clocks;
             return 0;
         }
 
         /* Advance forward the component's number of clocks */
         clocks            -= sim->vip.dp.clocks;
+        sim->vip.dp.until -= sim->vip.dp.clocks;
         sim->vip.dp.clocks = 0;
 
         /* Processing by operation phase */
@@ -401,6 +403,7 @@ static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
                 sim->vip.dp.clocks = vipClocksMs(3);
                 sim->vip.dp.fclk   = 1;
                 sim->vip.dp.step   = 1;
+                sim->vip.dp.until  = vipClocksMs(8);
                 vipThrow(sim, 0x0010); /* FRAMESTART */
                 /* TODO: Initiate drawing, throw GAMESTART */
                 /* ELSE: Set OVERTIME, throw TIMEERR */
@@ -437,6 +440,7 @@ static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
                 else sim->vip.dp.l1bsy = 0;
                 sim->vip.dp.clocks = vipClocksMs(2);
                 sim->vip.dp.step   = 4;
+                sim->vip.dp.until  = vipClocksMs(10);
                 vipThrow(sim, 0x0002); /* LFBEND */
                 break;
 
@@ -460,10 +464,14 @@ static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
 
                 /* Fallthrough */
             case 6: /* 13ms-18ms - Display right frame buffer */
+                if ((sim->vip.dp.column & 3) == 0)
+                    vipComputeBrightness(sim);
                 vipTransferColumn(sim, 1);
                 sim->vip.dp.clocks =
                     260 + (0xA94 >> sim->vip.dp.column % 12 & 1);
                 sim->vip.dp.column++;
+                if ((sim->vip.dp.column & 3) == 0)
+                    sim->vip.dp.cta -= 2;
                 if (sim->vip.dp.column == 384)
                     sim->vip.dp.step = 7;
                 break;
@@ -474,6 +482,7 @@ static int vipEmulateDisplay(VB *sim, uint32_t clocks) {
                 else sim->vip.dp.r1bsy = 0;
                 sim->vip.dp.clocks = vipClocksMs(2);
                 sim->vip.dp.step   = 0;
+                sim->vip.dp.until  = vipClocksMs(2);
                 vipThrow(sim, 0x0004); /* RFBEND */
                 if (vipOnFrame(sim))
                     return 1;
@@ -587,8 +596,8 @@ static void vipReset(VB *sim) {
 
 /* Determine how many clocks are guaranteed to process */
 static uint32_t vipUntil(VB *sim, uint32_t clocks) {
-    (void) sim;
-    /* Don't allow clocks to exceed interrupt conditions, even if disabled */
+    if (clocks > sim->vip.dp.until)
+        clocks = sim->vip.dp.until;
     return clocks;
 }