Properly handle 91-column EGA mode.

There's six pixels at the bottom that aren't part of text, and three
pixels on the right.

Don't touch the vmem when those pixels are updated... vmem can't
update them.

Should fix assertion in Abdul's Armor in RIP mode reported by DigitalMan
on IRC.

src/conio/bitmap_con.c

@@ -1773,14 +1773,16 @@ int bitmap_setpixel(uint32_t x, uint32_t y, uint32_t colour)
 		do_rwlock_unlock(&vstatlock);
 		return 0;
 	}
-	int off = vmem_cell_offset(vstat.vmem, xchar, ychar);
-	if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
-		pthread_mutex_unlock(&screenlock);
-		bitmap_draw_from_vmem(xchar + 1, ychar + 1, xchar + 1, ychar + 1);
-		pthread_mutex_lock(&screenlock);
+	if (xchar < vstat.cols && ychar < vstat.rows) {
+		int off = vmem_cell_offset(vstat.vmem, xchar, ychar);
+		if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
+			pthread_mutex_unlock(&screenlock);
+			bitmap_draw_from_vmem(xchar + 1, ychar + 1, xchar + 1, ychar + 1);
+			pthread_mutex_lock(&screenlock);
+		}
+		vstat.vmem->vmem[off].bg |= 0x04000000;
+		bitmap_drawn[off].bg |= 0x04000000;
 	}
-	vstat.vmem->vmem[off].bg |= 0x04000000;
-	bitmap_drawn[off].bg |= 0x04000000;
 	if (x < screena.screenwidth && y < screena.screenheight) {
 		if (screena.rect->data[pixel_offset(&screena, x, y)] != colour) {
 			screena.update_pixels = 1;
@@ -1847,35 +1849,42 @@ int bitmap_setpixels(uint32_t sx, uint32_t sy, uint32_t ex, uint32_t ey, uint32_
 	bool xupdated = false;
 	bool yupdated = false;
 	int off;
+	int crows = vstat.rows * vstat.charheight;
+	int ccols = vstat.cols * vstat.charwidth;
 	for (y = sy; y <= ey; y++) {
-		charx = charsx;
 		pos = pixels->width*(y-sy+y_off)+x_off;
-		if (!yupdated) {
+		bool in_text_area = y < crows;
+		if (in_text_area && !yupdated) {
+			charx = charsx;
 			off = vmem_cell_offset(vstat.vmem, charx, chary);
 		}
 		if (mask == NULL) {
 			for (x = sx; x <= ex; x++) {
-				if (!yupdated) {
-					if (!xupdated) {
-						if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
-							pthread_mutex_unlock(&screenlock);
-							bitmap_draw_from_vmem(charx + 1, chary + 1, charx + 1, chary + 1);
-							pthread_mutex_lock(&screenlock);
+				if (x >= ccols)
+					in_text_area = false;
+				if (in_text_area) {
+					if (!yupdated) {
+						if (!xupdated) {
+							if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
+								pthread_mutex_unlock(&screenlock);
+								bitmap_draw_from_vmem(charx + 1, chary + 1, charx + 1, chary + 1);
+								pthread_mutex_lock(&screenlock);
+							}
+							if (vstat.vmem && vstat.vmem->vmem) {
+								vstat.vmem->vmem[off].bg |= 0x04000000;
+							}
+							if (bitmap_drawn) {
+								bitmap_drawn[off].bg |= 0x04000000;
+							}
+							xupdated = true;
 						}
-						if (vstat.vmem && vstat.vmem->vmem) {
-							vstat.vmem->vmem[off].bg |= 0x04000000;
-						}
-						if (bitmap_drawn) {
-							bitmap_drawn[off].bg |= 0x04000000;
-						}
-						xupdated = true;
 					}
-				}
-				if (++cpx >= vstat.charwidth) {
-					cpx = 0;
-					charx++;
-					xupdated = false;
-					off = vmem_next_offset(vstat.vmem, off);
+					if (++cpx >= vstat.charwidth) {
+						cpx = 0;
+						charx++;
+						xupdated = false;
+						off = vmem_next_offset(vstat.vmem, off);
+					}
 				}
 				if (screena.rect->data[pixel_offset(&screena, x, y)] != pixels->pixels[pos]) {
 					screena.rect->data[pixel_offset(&screena, x, y)] = pixels->pixels[pos];
@@ -1899,27 +1908,31 @@ int bitmap_setpixels(uint32_t sx, uint32_t sy, uint32_t ex, uint32_t ey, uint32_
 		else {
 			mpos = mask->width * (y - sy + my_off) + mx_off;
 			for (x = sx; x <= ex; x++) {
-				if (!yupdated) {
-					if (!xupdated) {
-						if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
-							pthread_mutex_unlock(&screenlock);
-							bitmap_draw_from_vmem(charx + 1, chary + 1, charx + 1, chary + 1);
-							pthread_mutex_lock(&screenlock);
+				if (x >= ccols)
+					in_text_area = false;
+				if (in_text_area) {
+					if (!yupdated) {
+						if (!xupdated) {
+							if (!same_cell(&bitmap_drawn[off], &vstat.vmem->vmem[off])) {
+								pthread_mutex_unlock(&screenlock);
+								bitmap_draw_from_vmem(charx + 1, chary + 1, charx + 1, chary + 1);
+								pthread_mutex_lock(&screenlock);
+							}
+							if (vstat.vmem && vstat.vmem->vmem) {
+								vstat.vmem->vmem[off].bg |= 0x04000000;
+							}
+							if (bitmap_drawn) {
+								bitmap_drawn[off].bg |= 0x04000000;
+							}
+							xupdated = true;
 						}
-						if (vstat.vmem && vstat.vmem->vmem) {
-							vstat.vmem->vmem[off].bg |= 0x04000000;
-						}
-						if (bitmap_drawn) {
-							bitmap_drawn[off].bg |= 0x04000000;
-						}
-						xupdated = true;
 					}
-				}
-				if (++cpx >= vstat.charwidth) {
-					cpx = 0;
-					charx++;
-					xupdated = false;
-					off = vmem_next_offset(vstat.vmem, off);
+					if (++cpx >= vstat.charwidth) {
+						cpx = 0;
+						charx++;
+						xupdated = false;
+						off = vmem_next_offset(vstat.vmem, off);
+					}
 				}
 				mask_byte = mpos / 8;
 				mask_bit = mpos % 8;
@@ -1946,15 +1959,17 @@ int bitmap_setpixels(uint32_t sx, uint32_t sy, uint32_t ex, uint32_t ey, uint32_
 				mpos++;
 			}
 		}
-		cpy++;
-		if (cpy >= vstat.charheight) {
-			chary++;
-			cpy = 0;
-			yupdated = false;
-			xupdated = false;
+		if (y < crows) {
+			cpy++;
+			if (cpy >= vstat.charheight) {
+				chary++;
+				cpy = 0;
+				yupdated = false;
+				xupdated = false;
+			}
+			else
+				yupdated = true;
 		}
-		else
-			yupdated = true;
 	}
 	pthread_mutex_unlock(&screenlock);
 	do_rwlock_unlock(&vstatlock);