// 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) { if (offset < 0x080000) // rom return m_bios + (offset & 0x7ffff); else if (offset < 0x100000) // slot0 return m_ram_base + (offset & 0x7ffff); else if (offset < 0x200000) // slot1 return m_carts[1]->get_cart_base() + (offset & 0xfffff); else if (offset < 0x300000) // slot2 return m_carts[2]->get_cart_base() + (offset & 0xfffff); else if (offset < 0x400000) // slot3 return m_carts[3]->get_cart_base() + (offset & 0xfffff); return nullptr; } /*************************************************************************** Start the video hardware emulation. ***************************************************************************/ // Initialise the palette void z88_state::z88_palette(palette_device &palette) const { 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, BIT(data, 7 - b) ? pen1 : pen0); } } } 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, BIT(data, 7 - b) ? pen1 : pen0); } } } 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) { uint8_t byte0 = vram[(y * 0x100) + c]; uint8_t byte1 = vram[(y * 0x100) + c + 1]; // inverted graphics? uint16_t pen0 = 0; uint16_t pen1 = 0; if (byte1 & Z88_SCR_HW_REV) pen0 = (byte1 & Z88_SCR_HW_GRY) ? 2 : 1; else 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 const uint16_t ch = (byte0 | (byte1 << 8)) & 0x1ff; uint8_t *char_gfx; if ((ch & 0x01c0) == 0x01c0) char_gfx = convert_address(lores0 << 9) + ((ch & 0x3f) << 3); else char_gfx = convert_address(lores1 << 12) + (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 const uint16_t ch = (byte0 | (byte1 << 8)) & 0x3ff; uint8_t *char_gfx; if (BIT(ch, 8)) char_gfx = convert_address(hires1 << 11) + ((ch & 0xff) << 3); else char_gfx = convert_address(hires0 << 13) + ((ch & 0xff) << 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; } } } }