void pc_render_gfx_4bpp(mame_bitmap *bitmap, struct crtc6845 *crtc,
const UINT8 *vram, const UINT16 *palette, int interlace)
{
int sx, sy, sh;
int offs = crtc6845_get_start(crtc)*2;
int lines = crtc6845_get_char_lines(crtc);
int height = crtc6845_get_char_height(crtc);
int columns = crtc6845_get_char_columns(crtc)*2;
if (!vram)
vram = videoram;
if (!palette)
palette = dummy_palette;
for (sy = 0; sy < lines; sy++)
{
for (sh = 0; sh < height; sh++)
{
UINT16 *dest = BITMAP_ADDR16(bitmap, sy * height + sh, 0);
const UINT8 *src = &vram[offs | ((sh % interlace) << 13)];
for (sx = 0; sx < columns; sx++)
{
UINT8 b = *(src++);
*(dest++) = palette[(b >> 4) & 0x0F];
*(dest++) = palette[(b >> 0) & 0x0F];
}
}
offs = (offs + columns) & 0x1fff;
}
}
int crtc6845_port_w(struct crtc6845 *crtc, int offset, UINT8 data)
{
struct crtc6845_cursor cursor;
int idx;
UINT8 mask;
if (offset & 1)
{
/* write to a 6845 register, if supported */
idx = crtc->idx & 0x1f;
if (idx < (sizeof(crtc->reg) / sizeof(crtc->reg[0])))
{
mask = crtc6845_reg_mask[crtc->config.personality][idx].store_mask;
/* Don't zero out bits not covered by the mask. */
crtc->reg[crtc->idx] &= ~mask;
crtc->reg[crtc->idx] |= (data & mask);
/* are there special consequences to writing to this register? */
switch (idx) {
case 0xa:
case 0xb:
case 0xe:
case 0xf:
crtc6845_get_cursor(crtc, &cursor);
if (crtc->config.cursor_changed)
crtc->config.cursor_changed(&cursor);
break;
default:
schedule_full_refresh();
break;
}
/* since the PC1512 does not support the number of lines register directly,
* this value is keyed off of register 9
*/
if ((crtc->config.personality == M6845_PERSONALITY_PC1512) && (idx == 9))
{
UINT8 char_height;
char_height = crtc6845_get_char_height(crtc);
crtc6845_set_char_lines(crtc, 200 ); // / char_height);
}
return TRUE;
}
}
else
{
/* change the idx register */
crtc->idx = data;
}
return FALSE;
}
