// license:GPL-2.0+
// copyright-holders:Kevin Thacker,Sandro Ronco
/***************************************************************************
z88.c
Functions to emulate the video hardware of the Cambridge Z88
***************************************************************************/
#include "emu.h"
#include "includes/z88.h"
inline void z88_state::plot_pixel(bitmap_ind16 &bitmap, int x, int y, uint16_t color)
{
if (x<Z88_SCREEN_WIDTH)
bitmap.pix16(y, x) = color;
}
// convert absolute offset into correct address to get data from
inline uint8_t* z88_state::convert_address(uint32_t offset)
{
uint8_t *ptr = nullptr;
if (offset < 0x080000) // rom
ptr = m_bios + (offset & 0x7ffff);
else if (offset < 0x100000) // slot0
ptr = m_ram_base + (offset & 0x7ffff);
else if (offset < 0x200000) // slot1
ptr = m_carts[1]->get_cart_base() + (offset & 0xfffff);
else if (offset < 0x300000) // slot2
ptr = m_carts[2]->get_cart_base() + (offset & 0xfffff);
else if (offset < 0x400000) // slot3
ptr = m_carts[3]->get_cart_base() + (offset & 0xfffff);
return ptr;
}
/***************************************************************************
Start the video hardware emulation.
***************************************************************************/
// Initialise the palette
PALETTE_INIT_MEMBER(z88_state, z88)
{
m_palette->set_pen_color(0, rgb_t(138, 146, 148));
m_palette->set_pen_color(1, rgb_t(92, 83, 88));
m_palette->set_pen_color(2, rgb_t(122, 126, 129));
}
/* temp - change to gfxelement structure */
void z88_state::vh_render_8x8(bitmap_ind16 &bitmap, int x, int y, uint16_t pen0, uint16_t pen1, uint8_t *gfx)
{
for (int h=0; h<8; h++)
{
uint8_t data = gfx[h];
for (int b=0; b<8; b++)
{
plot_pixel(bitmap, x+b, y+h, (data & 0x80) ? pen1 : pen0);
data = data<<1;
}
}
}
void z88_state::vh_render_6x8(bitmap_ind16 &bitmap, int x, int y, uint16_t pen0, uint16_t pen1, uint8_t *gfx)
{
for (int h=0; h<8; h++)
{
uint8_t data = gfx[h]<<2;
for (int b=0; b<6; b++)
{
plot_pixel(bitmap, x+1+b, y+h, (data & 0x80) ? pen1 : pen0);
data = data<<1;
}
}
}
void z88_state::vh_render_line(bitmap_ind16 &bitmap, int x, int y, uint16_t pen)
{
for (int i=0; i<8; i++)
plot_pixel(bitmap, x + i, y + 7, pen);
}
UPD65031_SCREEN_UPDATE(z88_state::lcd_update)
{
if (sbf == 0)
{
// LCD disabled
bitmap.fill(0);
}
else
{
uint8_t *vram = convert_address(sbf<<11);
for (int y=0; y<(Z88_SCREEN_HEIGHT>>3); y++)
{
int x = 0, c = 0;
while (x < Z88_SCREEN_WIDTH)
{
uint16_t pen0, pen1;
uint8_t *char_gfx;
uint8_t byte0 = vram[(y * 0x100) + c];
uint8_t byte1 = vram[(y * 0x100) + c + 1];
// inverted graphics?
if (byte1 & Z88_SCR_HW_REV)
{
pen0 = (byte1 & Z88_SCR_HW_GRY) ? 2 : 1;
pen1 = 0;
}
else
{
pen0 = 0;
pen1 = (byte1 & Z88_SCR_HW_GRY) ? 2 : 1;
}
if ((byte1 & Z88_SCR_HW_NULL) == Z88_SCR_HW_NULL)
{
// hidden
}
else if (!(byte1 & Z88_SCR_HW_HRS) || (((byte1 & Z88_SCR_HW_CURS) == Z88_SCR_HW_CURS)))
{
// low-res 6x8
uint16_t ch = (byte0 | (byte1<<8)) & 0x1ff;
if ((ch & 0x01c0) == 0x01c0)
{
ch &= 0x3f;
char_gfx = convert_address(lores0<<9);
}
else
{
char_gfx = convert_address(lores1<<12);
}
char_gfx += (ch<<3);
// cursor flash
if (flash && (byte1 & Z88_SCR_HW_CURS) == Z88_SCR_HW_CURS)
vh_render_6x8(bitmap, x,(y<<3), pen1, pen0, char_gfx);
else
vh_render_6x8(bitmap, x,(y<<3), pen0, pen1, char_gfx);
// underline?
if (byte1 & Z88_SCR_HW_UND)
vh_render_line(bitmap, x, (y<<3), pen1);
x += 6;
}
else if ((byte1 & Z88_SCR_HW_HRS) && !(byte1 & Z88_SCR_HW_REV))
{
// high-res 8x8
uint16_t ch = (byte0 | (byte1<<8)) & 0x3ff;
if (ch & 0x0100)
{
ch &= 0xff;
char_gfx = convert_address(hires1<<11);
}
else
{
ch &= 0xff;
char_gfx = convert_address(hires0<<13);
}
char_gfx += (ch<<3);
// flash
if ((byte1 & Z88_SCR_HW_FLS) && flash)
pen0 = pen1 = 0;
vh_render_8x8(bitmap, x,(y<<3), pen0, pen1, char_gfx);
x += 8;
}
// every char takes 2 bytes
c += 2;
}
}
}
}