few more accessors

diff -r 20597e3d2632 console.h
@@ -139,6 +139,11 @@
     return ds->depth;
 }
 
+static inline int ds_get_bytes_per_pixel(DisplayState *ds)
+{
+    return (ds->depth / 8);
+}
+
 typedef unsigned long console_ch_t;
 static inline void console_write_ch(console_ch_t *dest, uint32_t ch)
 {

diff -r 20597e3d2632 hw/sm501.c
@@ -940,7 +940,7 @@
 
 static inline int get_depth_index(DisplayState *s)
 {
-    switch(s->depth) {
+    switch(ds_get_bits_per_pixel(s)) {
     default:
     case 8:
 	return 0;

@@ -970,7 +970,7 @@
 
     uint8_t  * src = s->local_mem;
     int src_bpp = 0;
-    int dst_bpp = s->ds->depth / 8 + (s->ds->depth % 8 ? 1 : 0);
+    int dst_bpp = ds_get_bytes_per_pixel(s->ds) + (ds_get_bits_per_pixel(s->ds) % 8 ? 1 : 0);
     uint32_t * palette = (uint32_t *)&s->dc_palette[SM501_DC_CRT_PALETTE
 						    - SM501_DC_PANEL_PALETTE];
     int ds_depth_index = get_depth_index(s->ds);

@@ -1024,7 +1024,7 @@
 
 	/* draw line and change status */
 	if (update) {
-	    draw_line(&s->ds->data[y * width * dst_bpp], src, width, palette);
+	    draw_line(&(ds_get_data(s->ds)[y * width * dst_bpp]), src, width, palette);
 	    if (y_start < 0)
 		y_start = y;
 	    if (page0 < page_min)