Updated readme

README.md

@@ -15,8 +15,8 @@ For more detail, check out this post about how I started the project:
 [Making a 68000 Emulator in Rust](https://jabberwocky.ca/posts/2021-11-making_an_emulator.html)
 
 
-Running
--------
+Computie
+--------
 
 For Computie, it can do everything the 68k-SMT board can do, including run the
 monitor program and load the Computie OS kernel and boot it from the
@@ -32,6 +32,9 @@ host, and set up host routing.  The exact commands in
 `src/machines/computie.rs` might need to be adjusted to work on different
 hosts.
 
+TRS-80
+------
+
 For the TRS-80, it can run Level I or Level II Basic, but it doesn't yet
 support a cassette tape drive or floppy drive.  I haven't tested it that
 thoroughly either, so any help with it would be welcome.  I mostly made it to
@@ -40,16 +43,50 @@ Genesis emulator.  The frontend uses the
 [`minifb`](https://github.com/emoon/rust_minifb) rust crate to open a window
 and render the characters to screen, as well as accept input from the keyboard.
 ```
-cargo run -p moa-minifb --release --bin moa-trs-80 --
+cargo run -p moa-minifb --release --bin moa-trs-80
 ```
 By default it will start Level I Basic.  To use the other rom, add the option
 `--rom binaries/trs80/level2.rom`
 
-The Genesis emulator is a work in progress but can be run with:
+![alt text](images/trs-80-level-ii-basic.png)
+
+Sega Genesis/MegaDrive
+----------------------
+
+It can be run with:
 ```
-cargo run -p moa-minifb --release --bin moa-genesis
+cargo run -p moa-minifb --release --bin moa-genesis -- <ROM FILE>
 ```
 
+The Genesis emulator is a work in progress.  It can play a few games but some
+games won't run because the bank switching for the Z80 coprocessor is not
+working yet, and some games will hang waiting for the Z80 to respond.  For the
+video processor, the window layer is not drawn and the layer priority is not
+handled.  The horizontal scroll also doesn't work on a line-by-line basis so it
+tends to be quite jerky as you move, with the sprites and cells misaligned
+until you've moved one complete cell over (8x8 pixels).
+
+On the Sonic 2 title screen, the colours for Tails are wonky, probably because
+there's some trickery going on to get more than 16 colours per line, but the
+emulator currently renders the whole frame at once instead of line by line, so
+changes that should be made while the screen is updating don't show up
+![alt text](images/sega-genesis-sonic2-title.png)
+
+In the first one, it's mostly working but the bottom of the clouds should be a
+different colour.  Highlight/Shadow colours are not yet supported
+![alt text](sega-genesis-sonic2-start.png)
+
+I'm not yet sure why the clouds in the background are cut off suddenly
+![alt text](sega-genesis-sonic2-bridge.png)
+
+There are some graphics glitches in Earthworm Jim, but it's almost playable if it
+wasn't for the 'jump' button, which only makes him jump a few pixels
+![alt text](sega-genesis-earthworm-jim.png)
+
+
+General Options
+---------------
+
 By default, the minifb frontend will scale the window by 2.  This can be
 changed with the `--scale [1,2,4]` option.
 

frontends/moa-minifb/src/bin/moa-genesis.rs

@@ -1,14 +1,20 @@
 
 
 use moa_minifb;
-use moa::machines::genesis::build_genesis;
+use moa::machines::genesis::{build_genesis, SegaGenesisOptions};
 
 fn main() {
     let matches = moa_minifb::new("Sega Genesis/Mega Drive Emulator")
+        .arg("<ROM>        'ROM file to load (must be flat binary)'")
         .get_matches();
 
+    let mut options = SegaGenesisOptions::new();
+    if let Some(filename) = matches.value_of("ROM") {
+        options.rom = filename.to_string();
+    }
+
     moa_minifb::run(matches, |frontend| {
-        build_genesis(frontend)
+        build_genesis(frontend, options)
     });
 }
 

src/machines/genesis.rs

@@ -14,15 +14,29 @@ use crate::peripherals::genesis;
 use crate::host::traits::{Host};
 
 
-pub fn build_genesis<H: Host>(host: &mut H) -> Result<System, Error> {
+pub struct SegaGenesisOptions {
+    pub rom: String,
+}
+
+impl SegaGenesisOptions {
+    pub fn new() -> Self {
+        Self {
+            rom: "".to_string(),
+        }
+    }
+}
+
+pub fn build_genesis<H: Host>(host: &mut H, options: SegaGenesisOptions) -> Result<System, Error> {
     let mut system = System::new();
 
+    let mut rom = MemoryBlock::load(&options.rom).unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/GenTestV3.0.bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/HDRV_Genesis_Test_v1_4.bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/ComradeOj's tiny demo.bin").unwrap();
+    //let mut rom = MemoryBlock::load("binaries/genesis/Digital Rain demo.bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/Sonic The Hedgehog (W) (REV 00) [!].bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/Sonic The Hedgehog (W) (REV 01) [!].bin").unwrap();
-    let mut rom = MemoryBlock::load("binaries/genesis/Sonic the Hedgehog 2 (JUE) [!].bin").unwrap();
+    //let mut rom = MemoryBlock::load("binaries/genesis/Sonic the Hedgehog 2 (JUE) [!].bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/Sonic the Hedgehog 3 (U) [!].bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/Earthworm Jim (U) [h1].bin").unwrap();
     //let mut rom = MemoryBlock::load("binaries/genesis/Home Alone (beta).bin").unwrap();
@@ -50,7 +64,7 @@ pub fn build_genesis<H: Host>(host: &mut H) -> Result<System, Error> {
     let bus_request = coproc.bus_request.clone();
 
     system.add_addressable_device(0x00a00000, coproc_mem)?;
-    //system.add_device("coproc", wrap_transmutable(coproc))?;
+    system.add_device("coproc", wrap_transmutable(coproc))?;
 
 
 
@@ -65,27 +79,7 @@ pub fn build_genesis<H: Host>(host: &mut H) -> Result<System, Error> {
     system.add_peripheral("vdp", 0x00c00000, wrap_transmutable(vdp)).unwrap();
 
 
-    // TODO this is temporarily a 68010 because GenTest tests the CPU type by relying on the illegal instruction
-    // exception which is bypassed to Error and I don't want to un-bypass yet while testing
-    let mut cpu = M68k::new(M68kType::MC68010, 7_670_454, BusPort::new(0, 24, 16, system.bus.clone()));
-
-    //cpu.enable_tracing();
-    //cpu.add_breakpoint(0x206);
-    //cpu.add_breakpoint(0x1dd0);         // Sonic: some kind of palette fading function
-    //cpu.add_breakpoint(0x16ee);
-    //cpu.decoder.dump_disassembly(&mut system, 0x206, 0x2000);
-
-    //cpu.add_breakpoint(0x16a0e);
-    //cpu.add_breakpoint(0x16812);
-    //cpu.add_breakpoint(0x166ec);
-    //cpu.add_breakpoint(0x13e18);
-    //cpu.add_breakpoint(0x16570);
-    //cpu.add_breakpoint(0x1714);
-
-    //cpu.add_breakpoint(0x43c2);
-
-    //cpu.add_breakpoint(0x21a);
-
+    let mut cpu = M68k::new(M68kType::MC68000, 7_670_454, BusPort::new(0, 24, 16, system.bus.clone()));
     system.add_interruptable_device("cpu", wrap_transmutable(cpu)).unwrap();
 
     Ok(system)

src/peripherals/genesis/ym7101.rs

@@ -418,9 +418,8 @@ impl Ym7101State {
 
         for cell_y in 0..cells_v {
             for cell_x in 0..cells_h {
-                let pattern_addr = self.get_pattern_addr(cell_table, cell_x as usize, cell_y as usize);
-                let pattern = read_beu16(&self.vram[pattern_addr..]);
-                self.draw_pattern(frame, pattern, (cell_x << 3) as u32, (cell_y << 3) as u32);
+                let pattern_w = read_beu16(&self.vram[self.get_pattern_addr(cell_table, cell_x as usize, cell_y as usize)..]);
+                self.draw_pattern(frame, pattern_w, (cell_x << 3) as u32, (cell_y << 3) as u32);
             }
         }
     }