191 lines
7.0 KiB
Rust
191 lines
7.0 KiB
Rust
use crate::Word;
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use crate::memory::PeekPoke;
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#[derive(Copy, Clone, Debug, Eq, PartialEq)]
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struct DisplayRegisters {
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mode: u8,
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screen: u32,
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palette: u32,
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font: u32,
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height: u32,
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width: u32,
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row_offset: u32,
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col_offset: u32
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}
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impl Default for DisplayRegisters {
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fn default() -> Self {
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Self {
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mode: 6,
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screen: 0x10000,
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palette: 0x20000 - 0x100,
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font: 0x20000 - 0x100 - 0x2000,
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height: 60,
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width: 80,
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row_offset: 0,
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col_offset: 0
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}
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}
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}
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fn read_display_registers<P: PeekPoke>(machine: &P, start: Word) -> DisplayRegisters {
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DisplayRegisters {
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mode: machine.peek(start),
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screen: machine.peek24(start + 1),
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palette: machine.peek24(start + 4),
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font: machine.peek24(start + 7),
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height: machine.peek24(start + 10),
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width: machine.peek24(start + 13),
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row_offset: machine.peek24(start + 16),
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col_offset: machine.peek24(start + 19)
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}
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}
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fn init_display_registers<P: PeekPoke>(machine: &mut P, start: Word) {
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let dr = DisplayRegisters::default();
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machine.poke(start, dr.mode);
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machine.poke24(start + 1, dr.screen.into());
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machine.poke24(start + 4, dr.palette.into());
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machine.poke24(start + 7, dr.font.into());
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machine.poke24(start + 10, dr.height.into());
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machine.poke24(start + 13, dr.width.into());
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machine.poke24(start + 16, dr.row_offset.into());
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machine.poke24(start + 19, dr.col_offset.into());
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}
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fn init_font<P: PeekPoke>(machine: &mut P) {
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let bytes = include_bytes!("font.rom");
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let font_addr = DisplayRegisters::default().font;
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for (offset, byte) in bytes.into_iter().enumerate() {
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machine.poke(Word::from(font_addr + offset as u32), *byte)
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}
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}
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pub fn draw<P: PeekPoke>(machine: &P, frame: &mut[u8]) {
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let reg = read_display_registers(machine, 16.into());
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let (gfx, highres, paletted) = (reg.mode & 1 > 0, reg.mode & 2 > 0, reg.mode & 4 > 0);
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match (paletted, highres, gfx) {
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(true, true, true) => draw_paletted_high_gfx(machine, reg, frame),
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(false, true, true) => draw_direct_high_gfx(machine, reg, frame),
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(true, true, false) => draw_paletted_high_text(machine, reg, frame),
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(false, true, false) => draw_direct_high_text(machine, reg, frame),
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(_, _, _) => {panic!("Unimplemented mode {}", reg.mode)}
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}
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}
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pub fn reset<P: PeekPoke>(machine: &mut P) {
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init_display_registers(machine, 16.into());
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init_font(machine);
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init_palette(machine);
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}
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fn init_palette<P: PeekPoke>(machine: &mut P) {
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let palette_addr = read_display_registers(machine, Word::from(16)).palette;
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let default_palette = [
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0x00, 0x05, 0x65, 0x11, 0xa8, 0x49, 0xeb, 0xff,
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0xe1, 0xf4, 0xfc, 0x1c, 0x37, 0x8e, 0xee, 0xfa
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];
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for (i, b) in default_palette.into_iter().enumerate() {
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machine.poke(Word::from(palette_addr + i as u32), b);
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}
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}
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fn to_byte_address((x, y): (u32, u32), reg: DisplayRegisters) -> u32 {
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let row_start = (y + reg.row_offset % reg.height) * reg.width + reg.screen;
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((x + reg.col_offset) % reg.width) + row_start
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}
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fn draw_direct_high_gfx<P: PeekPoke>(machine: &P, reg: DisplayRegisters, frame: &mut [u8]) {
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for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
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let (display_row, display_col) = (i / 640, i % 640);
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let (vulcan_row, vulcan_col) = ((display_row >> 2) as u32, (display_col >> 2) as u32);
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let vb = machine.peek(Word::from(to_byte_address((vulcan_col, vulcan_row), reg)));
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let (red, green, blue) = (vb >> 5, (vb >> 3) & 7, (vb & 3) << 1);
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pixel[0] = red << 5;
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pixel[1] = green << 5;
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pixel[2] = blue << 5;
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pixel[3] = 0xff;
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}
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}
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fn draw_paletted_high_gfx<P: PeekPoke>(machine: &P, reg: DisplayRegisters, frame: &mut [u8]) {
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for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
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let (display_row, display_col) = (i / 640, i % 640);
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let (vulcan_row, vulcan_col) = ((display_row >> 2) as u32, (display_col >> 2) as u32);
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let addr = to_byte_address((vulcan_col, vulcan_row), reg);
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let color_idx = machine.peek(Word::from(addr));
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let color = machine.peek(Word::from(reg.palette + color_idx as u32));
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let (red, green, blue) = (color >> 5, (color >> 3) & 7, (color & 3) << 1);
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pixel[0] = red << 5;
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pixel[1] = green << 5;
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pixel[2] = blue << 5;
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pixel[3] = 0xff;
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}
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}
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fn draw_paletted_high_text<P: PeekPoke>(machine: &P, reg: DisplayRegisters, frame: &mut [u8]) {
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for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
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let (display_row, display_col) = (i / 640, i % 640);
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let (vulcan_row, vulcan_col) = ((display_row >> 3) as u32, (display_col >> 3) as u32);
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let addr = to_byte_address((vulcan_col, vulcan_row), reg);
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let char_idx= machine.peek(Word::from(addr));
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let (char_row, char_col) = (display_row % 8, display_col % 8);
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let char_byte = machine.peek(Word::from(reg.font + ((char_idx as u32) << 3) + char_row as u32));
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let color_addr = addr + (reg.width * reg.height);
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let color_byte = machine.peek(Word::from(color_addr));
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let (fg_color_idx, bg_color_idx) = (color_byte & 0xf, color_byte >> 4);
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let fg_color = machine.peek(Word::from(reg.palette + fg_color_idx as u32));
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let bg_color = machine.peek(Word::from(reg.palette + bg_color_idx as u32));
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let (fg_red, fg_green, fg_blue) = (fg_color >> 5, (fg_color >> 3) & 7, (fg_color & 3) << 1);
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let (bg_red, bg_green, bg_blue) = (bg_color >> 5, (bg_color >> 3) & 7, (bg_color & 3) << 1);
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if char_byte & (1 << (7 - char_col)) != 0 {
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pixel[0] = fg_red << 5;
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pixel[1] = fg_green << 5;
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pixel[2] = fg_blue << 5;
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} else {
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pixel[0] = bg_red << 5;
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pixel[1] = bg_green << 5;
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pixel[2] = bg_blue << 5;
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}
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pixel[3] = 0xff;
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}
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}
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fn draw_direct_high_text<P: PeekPoke>(machine: &P, reg: DisplayRegisters, frame: &mut [u8]) {
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for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
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let (display_row, display_col) = (i / 640, i % 640);
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let (vulcan_row, vulcan_col) = ((display_row >> 3) as u32, (display_col >> 3) as u32);
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let addr = to_byte_address((vulcan_col, vulcan_row), reg);
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let char_idx= machine.peek(Word::from(addr));
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let (char_row, char_col) = (display_row % 8, display_col % 8);
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let char_byte = machine.peek(Word::from(reg.font + ((char_idx as u32) << 3) + char_row as u32));
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let color_addr = addr + (reg.width * reg.height);
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let color = machine.peek(Word::from(color_addr));
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let (red, green, blue) = (color >> 5, (color >> 3) & 7, (color & 3) << 1);
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if char_byte & (1 << (7 - char_col)) != 0 {
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pixel[0] = red << 5;
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pixel[1] = green << 5;
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pixel[2] = blue << 5;
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} else {
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pixel[0] = 0;
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pixel[1] = 0;
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pixel[2] = 0;
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}
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pixel[3] = 0xff;
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}
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} |