diff --git a/src/video/vid_tandy.c b/src/video/vid_tandy.c
index 4244c3309..c3737eba3 100644
--- a/src/video/vid_tandy.c
+++ b/src/video/vid_tandy.c
@@ -396,35 +396,36 @@ vid_render(tandy_t *dev, int line, int hos_offs)
     uint16_t  dat;
     int       col;
     int       cols[4];
+    int       out_x;
 
     cols[0]       = (vid->array[2] & 0xf) + 16;
 
-    for (c = 0; c < hos_offs; c++) {
-        if (vid->array[3] & 4) {
-            buffer32->line[line][c] = cols[0];
-        } else if ((vid->mode & 0x12) == 0x12) {
-            buffer32->line[line][c] = 0;
-        } else {
-            buffer32->line[line][c] = buffer32->line[(line) + 1][c] = (vid->col & 15) + 16;
+    if (line >= 0) {
+        for (c = 0; c < hos_offs; c++) {
+            if (vid->array[3] & 4) {
+                    buffer32->line[line][c] = cols[0];
+            } else if ((vid->mode & 0x12) == 0x12) {
+                    buffer32->line[line][c] = 0;
+            } else {
+                    buffer32->line[line][c] = buffer32->line[(line) + 1][c] = (vid->col & 15) + 16;
+            }
         }
-    }
 
-    for (c = 0; c < 8 - vid->hsync_offset; c++) {
-        if (vid->array[3] & 4) {
+        for (c = 0; c < 8 - vid->hsync_offset; c++) {
             if (vid->mode & 1)
-                buffer32->line[line][c + (vid->crtc[1] << 3) + hos_offs] = cols[0];
+                out_x = c + (vid->crtc[1] << 3) + hos_offs;
             else
-                buffer32->line[line][c + (vid->crtc[1] << 4) + hos_offs] = cols[0];
-        } else if ((vid->mode & 0x12) == 0x12) {
-            if (vid->mode & 1)
-                buffer32->line[line][c + (vid->crtc[1] << 3) + hos_offs] = 0;
-            else
-                buffer32->line[line][c + (vid->crtc[1] << 4) + hos_offs] = 0;
-        } else {
-            if (vid->mode & 1)
-                buffer32->line[line][c + (vid->crtc[1] << 3) + hos_offs] = (vid->col & 15) + 16;
-            else
-                buffer32->line[line][c + (vid->crtc[1] << 4) + hos_offs] = (vid->col & 15) + 16;
+                out_x = c + (vid->crtc[1] << 4) + hos_offs;
+
+            if (out_x >= 0) {
+                if (vid->array[3] & 4) {
+                    buffer32->line[line][out_x] = cols[0];
+                } else if ((vid->mode & 0x12) == 0x12) {
+                    buffer32->line[line][out_x] = 0;
+                } else {
+                    buffer32->line[line][out_x] = (vid->col & 15) + 16;
+                }
+            }
         }
     }
 
@@ -432,24 +433,30 @@ vid_render(tandy_t *dev, int line, int hos_offs)
         for (x = 0; x < vid->crtc[1] * 2; x++) {
             dat = (vid->vram[(vid->memaddr << 1) & 0xffff] << 8) | vid->vram[((vid->memaddr << 1) + 1) & 0xffff];
             vid->memaddr++;
-            buffer32->line[line][(x << 2) + hos_offs] = vid->array[((dat >> 12) & 0xf) + 16] + 16;
-            buffer32->line[line][(x << 2) + hos_offs + 1] = vid->array[((dat >> 8) & 0xf) + 16] + 16;
-            buffer32->line[line][(x << 2) + hos_offs + 2] =  vid->array[((dat >> 4) & 0xf) + 16] + 16;
-            buffer32->line[line][(x << 2) + hos_offs + 3] = vid->array[(dat & 0xf) + 16] + 16;
+            out_x = (x << 2) + hos_offs;
+            if (line >= 0) {
+                if (out_x >= 0)     buffer32->line[line][out_x]     = vid->array[((dat >> 12) & 0xf) + 16] + 16;
+                if (out_x + 1 >= 0) buffer32->line[line][out_x + 1] = vid->array[((dat >> 8) & 0xf) + 16] + 16;
+                if (out_x + 2 >= 0) buffer32->line[line][out_x + 2] = vid->array[((dat >> 4) & 0xf) + 16] + 16;
+                if (out_x + 3 >= 0) buffer32->line[line][out_x + 3] = vid->array[(dat & 0xf) + 16] + 16;
+            }
         }
     } else if ((vid->array[3] & 0x10) && (vid->mode & 1)) { /*320x200x16*/
         for (x = 0; x < vid->crtc[1]; x++) {
             dat = (vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 3) * 0x2000)] << 8) |
                   vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 3) * 0x2000) + 1];
             vid->memaddr++;
-            buffer32->line[line][(x << 3) + hos_offs] = buffer32->line[line][(x << 3) + hos_offs + 1] =
-                vid->array[((dat >> 12) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 3) + hos_offs + 2] = buffer32->line[line][(x << 3) + hos_offs + 3] =
-                vid->array[((dat >> 8) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 3) + hos_offs + 4] = buffer32->line[line][(x << 3) + hos_offs + 5] =
-                vid->array[((dat >> 4) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 3) + hos_offs + 6] = buffer32->line[line][(x << 3) + hos_offs + 7] =
-                vid->array[(dat & vid->array[1] & 0x0f) + 16] + 16;
+            out_x = (x << 3) + hos_offs;
+            if (line >= 0) {
+                if (out_x >= 0)     buffer32->line[line][out_x] = buffer32->line[line][out_x + 1] =
+                    vid->array[((dat >> 12) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 2 >= 0) buffer32->line[line][out_x + 2] = buffer32->line[line][out_x + 3] =
+                    vid->array[((dat >> 8) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 4 >= 0) buffer32->line[line][out_x + 4] = buffer32->line[line][out_x + 5] =
+                    vid->array[((dat >> 4) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 6 >= 0) buffer32->line[line][out_x + 6] = buffer32->line[line][out_x + 7] =
+                    vid->array[(dat & vid->array[1] & 0x0f) + 16] + 16;
+            }
         }
     } else if (vid->array[3] & 0x10) { /*160x200x16*/
         for (x = 0; x < vid->crtc[1]; x++) {
@@ -460,18 +467,21 @@ vid_render(tandy_t *dev, int line, int hos_offs)
                 dat = (vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 3) * 0x2000)] << 8) |
                       vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 3) * 0x2000) + 1];
             vid->memaddr++;
-            buffer32->line[line][(x << 4) + hos_offs] = buffer32->line[line][(x << 4) + hos_offs + 1] =
-            buffer32->line[line][(x << 4) + hos_offs + 2] = buffer32->line[line][(x << 4) + hos_offs + 3] =
-                vid->array[((dat >> 12) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 4) + hos_offs + 4] = buffer32->line[line][(x << 4) + hos_offs + 5] =
-            buffer32->line[line][(x << 4) + hos_offs + 6] = buffer32->line[line][(x << 4) + hos_offs + 7] =
-                vid->array[((dat >> 8) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 4) + hos_offs + 8] = buffer32->line[line][(x << 4) + hos_offs + 9] =
-            buffer32->line[line][(x << 4) + hos_offs + 10] = buffer32->line[line][(x << 4) + hos_offs + 11] =
-                vid->array[((dat >> 4) & vid->array[1] & 0x0f) + 16] + 16;
-            buffer32->line[line][(x << 4) + hos_offs + 12] = buffer32->line[line][(x << 4) + hos_offs + 13] =
-            buffer32->line[line][(x << 4) + hos_offs + 14] = buffer32->line[line][(x << 4) + hos_offs + 15] =
-                vid->array[(dat & vid->array[1] & 0x0f) + 16] + 16;
+            out_x = (x << 4) + hos_offs;
+            if (line >= 0) {
+                if (out_x >= 0)      buffer32->line[line][out_x] = buffer32->line[line][out_x + 1] =
+                buffer32->line[line][out_x + 2] = buffer32->line[line][out_x + 3] =
+                    vid->array[((dat >> 12) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 4 >= 0)  buffer32->line[line][out_x + 4] = buffer32->line[line][out_x + 5] =
+                buffer32->line[line][out_x + 6] = buffer32->line[line][out_x + 7] =
+                    vid->array[((dat >> 8) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 8 >= 0)  buffer32->line[line][out_x + 8] = buffer32->line[line][out_x + 9] =
+                buffer32->line[line][out_x + 10] = buffer32->line[line][out_x + 11] =
+                    vid->array[((dat >> 4) & vid->array[1] & 0x0f) + 16] + 16;
+                if (out_x + 12 >= 0) buffer32->line[line][out_x + 12] = buffer32->line[line][out_x + 13] =
+                buffer32->line[line][out_x + 14] = buffer32->line[line][out_x + 15] =
+                    vid->array[(dat & vid->array[1] & 0x0f) + 16] + 16;
+            }
         }
     } else if (vid->array[3] & 0x08) { /*640x200x4 - this implementation is a complete guess!*/
         for (x = 0; x < vid->crtc[1]; x++) {
@@ -481,8 +491,10 @@ vid_render(tandy_t *dev, int line, int hos_offs)
             for (c = 0; c < 8; c++) {
                 chr = (dat >> 6) & 2;
                 chr |= ((dat >> 15) & 1);
-                buffer32->line[line][(x << 3) + hos_offs + c] =
-                    vid->array[(chr & vid->array[1]) + 16] + 16;
+                out_x = (x << 3) + hos_offs + c;
+                if (out_x >= 0 && line >= 0)
+                    buffer32->line[line][out_x] =
+                        vid->array[(chr & vid->array[1]) + 16] + 16;
                 dat <<= 1;
             }
         }
@@ -500,17 +512,27 @@ vid_render(tandy_t *dev, int line, int hos_offs)
                 cols[1] = vid->array[((attr & 15) & vid->array[1]) + 16] + 16;
                 cols[0] = vid->array[((attr >> 4) & vid->array[1]) + 16] + 16;
             }
-            if (vid->scanline & 8)  for (c = 0; c < 8; c++)
-                buffer32->line[line][(x << 3) + c + hos_offs] =
-                    ((chr >= 0xb3) && (chr <= 0xdf)) ? cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0] : cols[0];
-            else  for (c = 0; c < 8; c++) {
-                if (vid->scanline == 8)
-                    buffer32->line[line][(x << 3) + c + hos_offs] = cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0];
-                else
-                    buffer32->line[line][(x << 3) + c + hos_offs] = cols[(fontdat[chr][vid->scanline & 7] & (1 << (c ^ 7))) ? 1 : 0];
+            if (line >= 0) {
+                if (vid->scanline & 8)  for (c = 0; c < 8; c++) {
+                    out_x = (x << 3) + c + hos_offs;
+                    if (out_x >= 0)
+                        buffer32->line[line][out_x] =
+                            ((chr >= 0xb3) && (chr <= 0xdf)) ? cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0] : cols[0];
+                } else  for (c = 0; c < 8; c++) {
+                    out_x = (x << 3) + c + hos_offs;
+                    if (out_x >= 0) {
+                        if (vid->scanline == 8)
+                            buffer32->line[line][out_x] = cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0];
+                        else
+                            buffer32->line[line][out_x] = cols[(fontdat[chr][vid->scanline & 7] & (1 << (c ^ 7))) ? 1 : 0];
+                    }
+                }
+                if (drawcursor)  for (c = 0; c < 8; c++) {
+                    out_x = (x << 3) + c + hos_offs;
+                    if (out_x >= 0)
+                        buffer32->line[line][out_x] ^= 15;
+                }
             }
-            if (drawcursor)  for (c = 0; c < 8; c++)
-                buffer32->line[line][(x << 3) + c + hos_offs] ^= 15;
             vid->memaddr++;
         }
     } else if (!(vid->mode & 2)) {
@@ -528,22 +550,30 @@ vid_render(tandy_t *dev, int line, int hos_offs)
                 cols[0] = vid->array[((attr >> 4) & vid->array[1]) + 16] + 16;
             }
             vid->memaddr++;
-            if (vid->scanline & 8)  for (c = 0; c < 8; c++)
-                buffer32->line[line][(x << 4) + (c << 1) + hos_offs] =
-                buffer32->line[line][(x << 4) + (c << 1) + 1 + hos_offs] =
-                    ((chr >= 0xb3) && (chr <= 0xdf)) ? cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0] : cols[0];
-            else  for (c = 0; c < 8; c++) {
-                if (vid->scanline == 8)
-                    buffer32->line[line][(x << 4) + (c << 1) + hos_offs] =
-                    buffer32->line[line][(x << 4) + (c << 1) + 1 + hos_offs] =
-                        cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0];
-                else
-                    buffer32->line[line][(x << 4) + (c << 1) + hos_offs] =
-                    buffer32->line[line][(x << 4) + (c << 1) + 1 + hos_offs] =
-                        cols[(fontdat[chr][vid->scanline & 7] & (1 << (c ^ 7))) ? 1 : 0];
+            if (line >= 0) {
+                if (vid->scanline & 8)  for (c = 0; c < 8; c++) {
+                    out_x = (x << 4) + (c << 1) + hos_offs;
+                    if (out_x >= 0)     buffer32->line[line][out_x] =
+                        buffer32->line[line][out_x + 1] =
+                        ((chr >= 0xb3) && (chr <= 0xdf)) ? cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0] : cols[0];
+                } else  for (c = 0; c < 8; c++) {
+                    out_x = (x << 4) + (c << 1) + hos_offs;
+                    if (vid->scanline == 8) {
+                        if (out_x >= 0)     buffer32->line[line][out_x] =
+                            buffer32->line[line][out_x + 1] =
+                            cols[(fontdat[chr][7] & (1 << (c ^ 7))) ? 1 : 0];
+                    } else {
+                        if (out_x >= 0)     buffer32->line[line][out_x] =
+                            buffer32->line[line][out_x + 1] =
+                            cols[(fontdat[chr][vid->scanline & 7] & (1 << (c ^ 7))) ? 1 : 0];
+                    }
+                }
+                if (drawcursor)  for (c = 0; c < 16; c++) {
+                    out_x = (x << 4) + c + hos_offs;
+                    if (out_x >= 0)
+                        buffer32->line[line][out_x] ^= 15;
+                }
             }
-            if (drawcursor)  for (c = 0; c < 16; c++)
-                buffer32->line[line][(x << 4) + c + hos_offs] ^= 15;
         }
     } else if (!(vid->mode & 16)) {
         cols[0] = (vid->col & 15);
@@ -570,8 +600,9 @@ vid_render(tandy_t *dev, int line, int hos_offs)
                   vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 1) * 0x2000) + 1];
             vid->memaddr++;
             for (c = 0; c < 8; c++) {
-                buffer32->line[line][(x << 4) + (c << 1) + hos_offs] =
-                buffer32->line[line][(x << 4) + (c << 1) + 1 + hos_offs] = cols[dat >> 14];
+                out_x = (x << 4) + (c << 1) + hos_offs;
+                if (out_x >= 0 && line >= 0)     buffer32->line[line][out_x] =
+                buffer32->line[line][out_x + 1] = cols[dat >> 14];
                 dat <<= 2;
             }
         }
@@ -583,7 +614,9 @@ vid_render(tandy_t *dev, int line, int hos_offs)
                   vid->vram[((vid->memaddr << 1) & 0x1fff) + ((vid->scanline & 1) * 0x2000) + 1];
             vid->memaddr++;
             for (c = 0; c < 16; c++) {
-                buffer32->line[line][(x << 4) + c + hos_offs] = buffer32->line[(line) + 1][(x << 4) + c + hos_offs] = cols[dat >> 15];
+                out_x = (x << 4) + c + hos_offs;
+                if (out_x >= 0 && line >= 0)
+                    buffer32->line[line][out_x] = buffer32->line[(line) + 1][out_x] = cols[dat >> 15];
                 dat <<= 1;
             }
         }
@@ -595,18 +628,20 @@ vid_render_blank(tandy_t *dev, int line)
 {
     t1kvid_t *vid         = dev->vid;
 
-    if (vid->array[3] & 4) {
-        if (vid->mode & 1)
-            hline(buffer32, 0, line, (vid->crtc[1] << 3) + 16, (vid->array[2] & 0xf) + 16);
-        else
-            hline(buffer32, 0, line, (vid->crtc[1] << 4) + 16, (vid->array[2] & 0xf) + 16);
-    } else {
-        int cols = ((vid->mode & 0x12) == 0x12) ? 0 : (vid->col & 0xf) + 16;
+    if (line >= 0) {
+        if (vid->array[3] & 4) {
+            if (vid->mode & 1)
+                hline(buffer32, 0, line, (vid->crtc[1] << 3) + 16, (vid->array[2] & 0xf) + 16);
+            else
+                hline(buffer32, 0, line, (vid->crtc[1] << 4) + 16, (vid->array[2] & 0xf) + 16);
+        } else {
+            int cols = ((vid->mode & 0x12) == 0x12) ? 0 : (vid->col & 0xf) + 16;
 
-        if (vid->mode & 1)
-            hline(buffer32, 0, line, (vid->crtc[1] << 3) + 16, cols);
-        else
-            hline(buffer32, 0, line, (vid->crtc[1] << 4) + 16, cols);
+            if (vid->mode & 1)
+                hline(buffer32, 0, line, (vid->crtc[1] << 3) + 16, cols);
+            else
+                hline(buffer32, 0, line, (vid->crtc[1] << 4) + 16, cols);
+        }
     }
 }
 
@@ -621,10 +656,12 @@ vid_render_process(tandy_t *dev, int line)
     else
         x = (vid->crtc[1] << 4) + 16;
 
-    if (!dev->is_sl2 && vid->composite)
-        Composite_Process(vid->mode, 0, x >> 2, buffer32->line[line]);
-    else
-        video_process_8(x, line);
+    if (line >= 0) {
+        if (!dev->is_sl2 && vid->composite)
+            Composite_Process(vid->mode, 0, x >> 2, buffer32->line[line]);
+        else
+            video_process_8(x, line);
+    }
 }
 
 static void
@@ -639,8 +676,8 @@ vid_poll(void *priv)
     int       scanline_old;
     int       old_ma;
     int       hos_offs              = 8 + vid->hsync_offset;
-    int       displine_offs         = (vid->displine + vid->vsync_offset < 0) ? 0 : vid->displine + vid->vsync_offset;
-    int       displine_offs_double  = displine_offs << 1;
+    int       displine_offs         = vid->displine + vid->vsync_offset;
+    int       displine_offs_double  = (vid->displine << 1) + (vid->vsync_offset << 1);
 
     if (!vid->linepos) {
         timer_advance_u64(&vid->timer, vid->dispofftime);