Implement DMA, WIP

I have fought very hard against the rust ownership model,
In the end for DMA to play nice with my code, I had to resort to use
unsafe code for now..

The DMA implementation itself is not accurate to say the least, but will
have to do for now.

Tonc's dma_demo.gba plays but with a visual glitch.


Former-commit-id: 3b9cdcb2d09c78701290f2c48b77f9f3487e85c9

src/core/dma.rs

@@ -1,74 +1,210 @@
-// use super::arm7tdmi::{Addr, Bus};
+use std::collections::VecDeque;
-// use super::ioregs::consts::*;
-// use super::sysbus::SysBus;
-// use super::{EmuIoDev, Interrupt};
 
-// #[allow(non_camel_case_types)]
+use super::arm7tdmi::{Addr, Bus};
-// #[derive(Debug)]
+use super::sysbus::SysBus;
-// pub struct DmaChannel {
+use super::{Interrupt, IrqBitmask, SyncedIoDevice};
-//     src_ioreg: Addr, /* Source Address register */
-//     dst_ioreg: Addr, /* Destination Address register */
-//     wc_ioreg: Addr,  /* Word Count 14bit */
-// }
 
-// #[derive(Debug, Primitive)]
+use num::FromPrimitive;
-// enum DmaAddrControl {
-//     Increment = 0,
-//     Decrement = 1,
-//     Fixed = 2,
-//     IncrementReloadProhibited = 3,
-// }
 
-// #[derive(Debug)]
+#[derive(Debug)]
-// enum DmaTransferType {
+enum DmaTransferType {
-//     Xfer16bit,
+    Xfer16bit,
-//     Xfer32bit,
+    Xfer32bit,
-// }
+}
 
-// #[derive(Debug, Primitive)]
+#[derive(Debug)]
-// enum DmaStartTiming {
+pub struct DmaChannel {
-//     Immediately = 0,
+    id: usize,
-//     VBlank = 1,
-//     HBlank = 2,
-//     Special = 3,
-// }
 
-// #[derive(Debug)]
+    pub src: u32,
-// struct DmaControl {
+    pub dst: u32,
-//     dst_addr_ctl: DmaAddrControl,
+    pub wc: u32,
-//     src_addr_ctl: DmaAddrControl,
+    pub ctrl: DmaChannelCtrl,
-//     repeat: bool,
-//     xfer: DmaTransferType,
-//     start_timing: DmaStartTiming,
-//     irq_upon_end_of_wc: bool,
-//     enable: bool,
-// }
 
-// impl DmaChannel {
+    running: bool,
-//     pub fn new(src_ioreg: Addr, dst_ioreg: Addr, wc_ioreg: Addr) -> DmaChannel {
+    cycles: usize,
-//         DmaChannel {
+    start_cycles: usize,
-//             src_ioreg,
+    irq: Interrupt,
-//             dst_ioreg,
+}
-//             wc_ioreg,
-//         }
-//     }
 
-//     // fn src_addr(&self, sysbus: &SysBus) -> Addr {
+impl DmaChannel {
-//     //     sysbus.ioregs.read_32(self.src_ioreg - IO_BASE) as Addr
+    pub fn new(id: usize) -> DmaChannel {
-//     // }
+        if id > 3 {
+            panic!("invalid dma id {}", id);
+        }
+        DmaChannel {
+            id: id,
+            irq: Interrupt::from_usize(id + 8).unwrap(),
+            running: false,
+            src: 0,
+            dst: 0,
+            wc: 0,
+            ctrl: DmaChannelCtrl(0),
+            cycles: 0,
+            start_cycles: 0,
+        }
+    }
 
-//     // fn dst_addr(&self, sysbus: &SysBus) -> Addr {
+    pub fn is_running(&self) -> bool {
-//     //     sysbus.ioregs.read_32(self.dst_ioreg - IO_BASE) as Addr
+        self.running
-//     // }
+    }
 
-//     // fn word_count(&self, sysbus: &SysBus) -> usize {
+    pub fn write_src_low(&mut self, low: u16) {
-//     //     sysbus.ioregs.read_reg(self.wc_ioreg) as usize
+        let src = self.src;
-//     // }
+        self.src = (src & 0xffff0000) | (low as u32);
-// }
+    }
 
-// impl EmuIoDev for DmaChannel {
+    pub fn write_src_high(&mut self, high: u16) {
-//     fn step(&mut self, cycles: usize, sysbus: &mut SysBus) -> (usize, Option<Interrupt>) {
+        let src = self.src;
-//         // TODO
+        let high = high as u32;
-//         (0, None)
+        self.src = (src & 0xffff) | (high << 16);
-//     }
+    }
-// }
+
+    pub fn write_dst_low(&mut self, low: u16) {
+        let dst = self.dst;
+        self.dst = (dst & 0xffff0000) | (low as u32);
+    }
+
+    pub fn write_dst_high(&mut self, high: u16) {
+        let dst = self.dst;
+        let high = high as u32;
+        self.dst = (dst & 0xffff) | (high << 16);
+    }
+
+    pub fn write_word_count(&mut self, value: u16) {
+        self.wc = value as u32;
+    }
+
+    pub fn write_dma_ctrl(&mut self, value: u16) -> bool {
+        let ctrl = DmaChannelCtrl(value);
+        let mut start_immediately = false;
+        if ctrl.is_enabled() {
+            self.start_cycles = self.cycles;
+            self.running = true;
+            if ctrl.timing() == 0 {
+                start_immediately = true;
+            }
+        }
+        self.ctrl = ctrl;
+        return start_immediately;
+    }
+
+    fn xfer(&mut self, sb: &mut SysBus, irqs: &mut IrqBitmask) {
+        let word_size = if self.ctrl.is_32bit() { 4 } else { 2 };
+        let dst_rld = self.dst;
+        for word in 0..self.wc {
+            if word_size == 4 {
+                let w = sb.read_32(self.src);
+                sb.write_32(self.dst, w)
+            } else {
+                let hw = sb.read_16(self.src);
+                // println!("src {:x} dst {:x}", self.src, self.dst);
+                sb.write_16(self.dst, hw)
+            }
+            match self.ctrl.src_adj() {
+                /* Increment */ 0 => self.src += word_size,
+                /* Decrement */ 1 => self.src -= word_size,
+                /* Fixed */ 2 => {}
+                _ => panic!("forbidden DMA source address adjustment"),
+            }
+            match self.ctrl.dst_adj() {
+                /* Increment[+Reload] */ 0 | 3 => self.dst += word_size,
+                /* Decrement */ 1 => self.dst -= word_size,
+                /* Fixed */ 2 => {}
+                _ => panic!("forbidden DMA dest address adjustment"),
+            }
+        }
+        if self.ctrl.is_triggering_irq() {
+            irqs.add_irq(self.irq);
+        }
+        if self.ctrl.repeat() {
+            self.start_cycles = self.cycles;
+            /* reload */
+            if 3 == self.ctrl.dst_adj() {
+                self.dst = dst_rld;
+            }
+        } else {
+            self.running = false;
+            self.ctrl.set_enabled(false);
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct DmaController {
+    pub channels: [DmaChannel; 4],
+    xfers_queue: VecDeque<usize>,
+    cycles: usize,
+}
+
+impl DmaController {
+    pub fn new() -> DmaController {
+        DmaController {
+            channels: [
+                DmaChannel::new(0),
+                DmaChannel::new(1),
+                DmaChannel::new(2),
+                DmaChannel::new(3),
+            ],
+            xfers_queue: VecDeque::new(),
+            cycles: 0,
+        }
+    }
+
+    pub fn perform_work(&mut self, sb: &mut SysBus, irqs: &mut IrqBitmask) -> bool {
+        if self.xfers_queue.is_empty() {
+            false
+        } else {
+            while let Some(id) = self.xfers_queue.pop_front() {
+                self.channels[id].xfer(sb, irqs)
+            }
+            true
+        }
+    }
+
+    pub fn write_16(&mut self, channel_id: usize, ofs: u32, value: u16) {
+        match ofs {
+            0 => self.channels[channel_id].write_src_low(value),
+            2 => self.channels[channel_id].write_src_high(value),
+            4 => self.channels[channel_id].write_dst_low(value),
+            6 => self.channels[channel_id].write_dst_high(value),
+            8 => self.channels[channel_id].write_word_count(value),
+            10 => {
+                if self.channels[channel_id].write_dma_ctrl(value) {
+                    self.xfers_queue.push_back(channel_id)
+                }
+            }
+            _ => panic!("Invalid dma offset"),
+        }
+    }
+
+    pub fn notify_vblank(&mut self) {
+        for i in 0..4 {
+            if self.channels[i].ctrl.is_enabled() && self.channels[i].ctrl.timing() == 1 {
+                self.xfers_queue.push_back(i);
+            }
+        }
+    }
+
+    pub fn notify_hblank(&mut self) {
+        for i in 0..4 {
+            if self.channels[i].ctrl.is_enabled() && self.channels[i].ctrl.timing() == 2 {
+                self.xfers_queue.push_back(i);
+            }
+        }
+    }
+}
+
+bitfield! {
+    #[derive(Default)]
+    pub struct DmaChannelCtrl(u16);
+    impl Debug;
+    u16;
+    dst_adj, _ : 6, 5;
+    src_adj, _ : 8, 7;
+    repeat, _ : 9;
+    is_32bit, _: 10;
+    timing, _: 13, 12;
+    is_triggering_irq, _: 14;
+    is_enabled, set_enabled: 15;
+}

src/core/gba.rs

@@ -1,42 +1,19 @@
 /// Struct containing everything
-///
-use std::cell::RefCell;
-use std::rc::Rc;
-
 use super::arm7tdmi::{exception::Exception, Core, DecodedInstruction};
 use super::cartridge::Cartridge;
 use super::gpu::*;
 use super::interrupt::*;
-use super::ioregs::IoRegs;
+use super::iodev::*;
 use super::sysbus::SysBus;
-use super::timer::Timers;
+
 use super::GBAResult;
 use super::SyncedIoDevice;
 use crate::backend::*;
 
-#[derive(Debug)]
-pub struct IoDevices {
-    pub intc: InterruptController,
-    pub gpu: Gpu,
-    pub timers: Timers,
-}
-
-impl IoDevices {
-    pub fn new() -> IoDevices {
-        IoDevices {
-            intc: InterruptController::new(),
-            gpu: Gpu::new(),
-            timers: Timers::new(),
-        }
-    }
-}
-
 pub struct GameBoyAdvance {
-    backend: Box<EmulatorBackend>,
+    backend: Box<dyn EmulatorBackend>,
     pub cpu: Core,
-    pub sysbus: SysBus,
+    pub sysbus: Box<SysBus>,
-
-    pub io: Rc<RefCell<IoDevices>>,
 }
 
 impl GameBoyAdvance {
@@ -44,51 +21,63 @@ impl GameBoyAdvance {
         cpu: Core,
         bios_rom: Vec<u8>,
         gamepak: Cartridge,
-        backend: Box<EmulatorBackend>,
+        backend: Box<dyn EmulatorBackend>,
     ) -> GameBoyAdvance {
-        let io = Rc::new(RefCell::new(IoDevices::new()));
+        let io = IoDevices::new();
-
-        let ioregs = IoRegs::new(io.clone());
-        let sysbus = SysBus::new(io.clone(), bios_rom, gamepak, ioregs);
-
         GameBoyAdvance {
             backend: backend,
             cpu: cpu,
-            sysbus: sysbus,
+            sysbus: Box::new(SysBus::new(io, bios_rom, gamepak)),
-
-            io: io.clone(),
         }
     }
 
     pub fn frame(&mut self) {
         self.update_key_state();
-        while self.io.borrow().gpu.state != GpuState::VBlank {
+        while self.sysbus.io.gpu.state != GpuState::VBlank {
-            let cycles = self.emulate_cpu();
+            self.step_new();
-            self.emulate_peripherals(cycles);
         }
-        self.backend.render(self.io.borrow().gpu.get_framebuffer());
+        self.backend.render(self.sysbus.io.gpu.get_framebuffer());
-        while self.io.borrow().gpu.state == GpuState::VBlank {
+        while self.sysbus.io.gpu.state == GpuState::VBlank {
-            let cycles = self.emulate_cpu();
+            self.step_new();
-            self.emulate_peripherals(cycles);
         }
     }
 
     fn update_key_state(&mut self) {
-        self.sysbus.ioregs.keyinput = self.backend.get_key_state();
+        self.sysbus.io.keyinput = self.backend.get_key_state();
     }
 
-    pub fn emulate_cpu(&mut self) -> usize {
+    // TODO deprecate
+    pub fn step(&mut self) -> GBAResult<DecodedInstruction> {
         let previous_cycles = self.cpu.cycles;
-        self.cpu.step(&mut self.sysbus).unwrap();
+        let executed_insn = self.cpu.step_one(&mut self.sysbus)?;
-        self.cpu.cycles - previous_cycles
+        let cycles = self.cpu.cycles - previous_cycles;
+        Ok(executed_insn)
     }
 
-    pub fn emulate_peripherals(&mut self, cycles: usize) {
+    pub fn step_new(&mut self) {
         let mut irqs = IrqBitmask(0);
-        let mut io = self.io.borrow_mut();
+        let previous_cycles = self.cpu.cycles;
+
+        // // I hate myself for doing this, but rust left me no choice.
+        let io = unsafe {
+            let ptr = &mut *self.sysbus as *mut SysBus;
+            &mut (*ptr).io as &mut IoDevices
+        };
+
+        if !io.dmac.perform_work(&mut self.sysbus, &mut irqs) {
+            self.cpu.step(&mut self.sysbus).unwrap();
+        }
+
+        let cycles = self.cpu.cycles - previous_cycles;
 
         io.timers.step(cycles, &mut self.sysbus, &mut irqs);
-        io.gpu.step(cycles, &mut self.sysbus, &mut irqs);
+        if let Some(new_gpu_state) = io.gpu.step(cycles, &mut self.sysbus, &mut irqs) {
+            match new_gpu_state {
+                GpuState::VBlank => io.dmac.notify_vblank(),
+                GpuState::HBlank => io.dmac.notify_hblank(),
+                _ => {}
+            }
+        }
 
         if !self.cpu.cpsr.irq_disabled() {
             io.intc.request_irqs(irqs);
@@ -97,18 +86,4 @@ impl GameBoyAdvance {
             }
         }
     }
-
-    pub fn step(&mut self) -> GBAResult<DecodedInstruction> {
-        let previous_cycles = self.cpu.cycles;
-        let executed_insn = self.cpu.step_one(&mut self.sysbus)?;
-        let cycles = self.cpu.cycles - previous_cycles;
-
-        self.emulate_peripherals(cycles);
-
-        if self.io.borrow().gpu.state == GpuState::VBlank {
-            self.backend.render(self.io.borrow().gpu.get_framebuffer());
-        }
-
-        Ok(executed_insn)
-    }
 }

src/core/gpu/mod.rs

@@ -361,7 +361,7 @@ impl Gpu {
     }
 
     fn scanline_aff_bg(&mut self, bg: usize, sb: &mut SysBus) {
-      // TODO
+        // TODO
     }
 
     fn scanline_mode3(&mut self, bg: usize, sb: &mut SysBus) {
@@ -444,10 +444,14 @@ impl Gpu {
     pub fn get_framebuffer(&self) -> &[u32] {
         &self.frame_buffer.0
     }
-}
 
-impl SyncedIoDevice for Gpu {
+    // Returns the new gpu state
-    fn step(&mut self, cycles: usize, sb: &mut SysBus, irqs: &mut IrqBitmask) {
+    pub fn step(
+        &mut self,
+        cycles: usize,
+        sb: &mut SysBus,
+        irqs: &mut IrqBitmask,
+    ) -> Option<GpuState> {
         self.cycles += cycles;
 
         if self.dispstat.vcount_setting() != 0 {
@@ -472,12 +476,14 @@ impl SyncedIoDevice for Gpu {
                             irqs.set_LCD_HBlank(true);
                         };
                         self.state = HBlank;
+                        return Some(HBlank);
                     } else {
                         self.dispstat.set_vblank(true);
                         if self.dispstat.vblank_irq_enable() {
                             irqs.set_LCD_VBlank(true);
                         };
                         self.state = VBlank;
+                        return Some(VBlank);
                     };
                 }
             }
@@ -487,6 +493,7 @@ impl SyncedIoDevice for Gpu {
                     self.state = HDraw;
                     self.dispstat.set_hblank(false);
                     self.dispstat.set_vblank(false);
+                    return Some(HDraw);
                 }
             }
             VBlank => {
@@ -497,9 +504,12 @@ impl SyncedIoDevice for Gpu {
                     self.dispstat.set_vblank(false);
                     self.current_scanline = 0;
                     self.render_scanline(sb);
+                    return Some(HDraw);
                 }
             }
         }
+
+        return None;
     }
 }
 

src/core/iodev.rs

@@ -1,28 +1,35 @@
-use std::cell::RefCell;
-use std::rc::Rc;
-
 use super::arm7tdmi::{Addr, Bus};
-use super::gba::IoDevices;
+use super::dma::DmaController;
 use super::gpu::regs::WindowFlags;
+use super::gpu::*;
+use super::interrupt::InterruptController;
 use super::keypad;
 use super::sysbus::BoxedMemory;
+use super::timer::Timers;
 
 use consts::*;
 
 #[derive(Debug)]
-pub struct IoRegs {
+pub struct IoDevices {
-    mem: BoxedMemory,
+    pub intc: InterruptController,
-    pub io: Rc<RefCell<IoDevices>>,
+    pub gpu: Gpu,
+    pub timers: Timers,
+    pub dmac: DmaController,
     pub keyinput: u16,
     pub post_boot_flag: bool,
     pub waitcnt: WaitControl, // TODO also implement 4000800
+
+    mem: BoxedMemory,
 }
 
-impl IoRegs {
+impl IoDevices {
-    pub fn new(io: Rc<RefCell<IoDevices>>) -> IoRegs {
+    pub fn new() -> IoDevices {
-        IoRegs {
+        IoDevices {
+            gpu: Gpu::new(),
+            timers: Timers::new(),
+            dmac: DmaController::new(),
+            intc: InterruptController::new(),
             mem: BoxedMemory::new(vec![0; 0x800].into_boxed_slice()),
-            io: io,
             post_boot_flag: false,
             keyinput: keypad::KEYINPUT_ALL_RELEASED,
             waitcnt: WaitControl(0),
@@ -30,14 +37,15 @@ impl IoRegs {
     }
 }
 
-impl Bus for IoRegs {
+impl Bus for IoDevices {
     fn read_32(&self, addr: Addr) -> u32 {
         (self.read_16(addr + 2) as u32) << 16 | (self.read_16(addr) as u32)
     }
 
     fn read_16(&self, addr: Addr) -> u16 {
-        let io = self.io.borrow();
+        let io = self;
-        match addr + IO_BASE {
+        let io_addr = addr + IO_BASE;
+        match io_addr {
             REG_DISPCNT => io.gpu.dispcnt.0,
             REG_DISPSTAT => io.gpu.dispstat.0,
             REG_VCOUNT => io.gpu.current_scanline as u16,
@@ -71,12 +79,24 @@ impl Bus for IoRegs {
             REG_TM3CNT_L => io.timers[3].timer_data,
             REG_TM3CNT_H => io.timers[3].timer_ctl.0,
 
-            REG_WAITCNT => self.waitcnt.0,
+            REG_DMA0CNT_H => io.dmac.channels[0].ctrl.0,
+            REG_DMA1CNT_H => io.dmac.channels[1].ctrl.0,
+            REG_DMA2CNT_H => io.dmac.channels[2].ctrl.0,
+            REG_DMA3CNT_H => io.dmac.channels[3].ctrl.0,
 
-            REG_POSTFLG => self.post_boot_flag as u16,
+            REG_WAITCNT => io.waitcnt.0,
+
+            REG_POSTFLG => io.post_boot_flag as u16,
             REG_HALTCNT => 0,
-            REG_KEYINPUT => self.keyinput as u16,
+            REG_KEYINPUT => io.keyinput as u16,
-            _ => self.mem.read_16(addr),
+            _ => {
+                println!(
+                    "Unimplemented read from {:x} {}",
+                    io_addr,
+                    io_reg_string(io_addr)
+                );
+                io.mem.read_16(addr)
+            }
         }
     }
 
@@ -95,8 +115,10 @@ impl Bus for IoRegs {
     }
 
     fn write_16(&mut self, addr: Addr, value: u16) {
-        let mut io = self.io.borrow_mut();
+        let mut io = self;
-        match addr + IO_BASE {
+        io.mem.write_16(addr, value);
+        let io_addr = addr + IO_BASE;
+        match io_addr {
             REG_DISPCNT => io.gpu.dispcnt.0 = value,
             REG_DISPSTAT => io.gpu.dispstat.0 |= value & !3,
             REG_BG0CNT => io.gpu.bg[0].bgcnt.0 = value,
@@ -192,18 +214,22 @@ impl Bus for IoRegs {
             }
             REG_TM3CNT_H => io.timers[3].timer_ctl.0 = value,
 
-            REG_WAITCNT => self.waitcnt.0 = value,
+            DMA_BASE..=REG_DMA3CNT_H => {
+                let ofs = io_addr - DMA_BASE;
+                let channel_id = (ofs / 12) as usize;
+                io.dmac.write_16(channel_id, ofs % 12, value)
+            }
 
-            REG_POSTFLG => self.post_boot_flag = value != 0,
+            REG_WAITCNT => io.waitcnt.0 = value,
+
+            REG_POSTFLG => io.post_boot_flag = value != 0,
             REG_HALTCNT => {}
             _ => {
-                let ioreg_addr = IO_BASE + addr;
                 println!(
                     "Unimplemented write to {:x} {}",
-                    ioreg_addr,
+                    io_addr,
-                    io_reg_string(ioreg_addr)
+                    io_reg_string(io_addr)
                 );
-                self.mem.write_16(addr, value);
             }
         }
     }
@@ -301,6 +327,7 @@ pub mod consts {
     pub const REG_WAVE_RAM: Addr = 0x0400_0090;     //              Channel 3 Wave Pattern RAM (2 banks!!)
     pub const REG_FIFO_A: Addr = 0x0400_00A0;       //  4    W      Channel A FIFO, Data 0-3
     pub const REG_FIFO_B: Addr = 0x0400_00A4;       //  4    W      Channel B FIFO, Data 0-3
+    pub const DMA_BASE: Addr = REG_DMA0SAD;
     pub const REG_DMA0SAD: Addr = 0x0400_00B0;      //  4    W      DMA 0 Source Address
     pub const REG_DMA0DAD: Addr = 0x0400_00B4;      //  4    W      DMA 0 Destination Address
     pub const REG_DMA0CNT_L: Addr = 0x0400_00B8;    //  2    W      DMA 0 Word Count

src/core/mod.rs

@@ -4,7 +4,7 @@ pub mod gpu;
 pub mod sysbus;
 pub use sysbus::SysBus;
 pub mod interrupt;
-pub mod ioregs;
+pub mod iodev;
 pub use interrupt::Interrupt;
 pub use interrupt::IrqBitmask;
 pub mod gba;

src/core/sysbus.rs

@@ -1,15 +1,13 @@
-use std::cell::RefCell;
 use std::fmt;
 use std::ops::Add;
-use std::rc::Rc;
 
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 
 use super::arm7tdmi::bus::Bus;
 use super::arm7tdmi::Addr;
-use super::gba::IoDevices;
+use super::cartridge::Cartridge;
 use super::gpu::GpuState;
-use super::{cartridge::Cartridge, ioregs::IoRegs};
+use super::iodev::IoDevices;
 
 const VIDEO_RAM_SIZE: usize = 128 * 1024;
 const WORK_RAM_SIZE: usize = 256 * 1024;
@@ -141,13 +139,11 @@ impl Bus for DummyBus {
 
 #[derive(Debug)]
 pub struct SysBus {
-    pub io: Rc<RefCell<IoDevices>>,
+    pub io: IoDevices,
 
     bios: BoxedMemory,
     onboard_work_ram: BoxedMemory,
     internal_work_ram: BoxedMemory,
-    /// Currently model the IOMem as regular buffer, later make it into something more sophisticated.
-    pub ioregs: IoRegs,
     pub palette_ram: BoxedMemory,
     pub vram: BoxedMemory,
     pub oam: BoxedMemory,
@@ -156,19 +152,13 @@ pub struct SysBus {
 }
 
 impl SysBus {
-    pub fn new(
+    pub fn new(io: IoDevices, bios_rom: Vec<u8>, gamepak: Cartridge) -> SysBus {
-        io: Rc<RefCell<IoDevices>>,
-        bios_rom: Vec<u8>,
-        gamepak: Cartridge,
-        ioregs: IoRegs,
-    ) -> SysBus {
         SysBus {
             io: io,
 
             bios: BoxedMemory::new(bios_rom.into_boxed_slice()),
             onboard_work_ram: BoxedMemory::new(vec![0; WORK_RAM_SIZE].into_boxed_slice()),
             internal_work_ram: BoxedMemory::new(vec![0; INTERNAL_RAM_SIZE].into_boxed_slice()),
-            ioregs: ioregs,
             palette_ram: BoxedMemory::new(vec![0; PALETTE_RAM_SIZE].into_boxed_slice()),
             vram: BoxedMemory::new(vec![0; VIDEO_RAM_SIZE].into_boxed_slice()),
             oam: BoxedMemory::new(vec![0; OAM_SIZE].into_boxed_slice()),
@@ -177,13 +167,13 @@ impl SysBus {
         }
     }
 
-    fn map(&self, addr: Addr) -> (&Bus, Addr) {
+    fn map(&self, addr: Addr) -> (&dyn Bus, Addr) {
         let ofs = addr & 0x00ff_ffff;
         match addr & 0xff000000 {
             BIOS_ADDR => (&self.bios, ofs),
             EWRAM_ADDR => (&self.onboard_work_ram, ofs & 0x3_ffff),
             IWRAM_ADDR => (&self.internal_work_ram, ofs & 0x7fff),
-            IOMEM_ADDR => (&self.ioregs, {
+            IOMEM_ADDR => (&self.io, {
                 if ofs & 0xffff == 0x8000 {
                     0x800
                 } else {
@@ -205,13 +195,13 @@ impl SysBus {
     }
 
     /// TODO proc-macro for generating this function
-    fn map_mut(&mut self, addr: Addr) -> (&mut Bus, Addr) {
+    fn map_mut(&mut self, addr: Addr) -> (&mut dyn Bus, Addr) {
         let ofs = addr & 0x00ff_ffff;
         match addr & 0xff000000 {
             BIOS_ADDR => (&mut self.bios, ofs),
             EWRAM_ADDR => (&mut self.onboard_work_ram, ofs & 0x3_ffff),
             IWRAM_ADDR => (&mut self.internal_work_ram, ofs & 0x7fff),
-            IOMEM_ADDR => (&mut self.ioregs, {
+            IOMEM_ADDR => (&mut self.io, {
                 if ofs & 0xffff == 0x8000 {
                     0x800
                 } else {
@@ -249,24 +239,24 @@ impl SysBus {
                     MemoryAccessWidth::MemoryAccess32 => cycles += 2,
                     _ => cycles += 1,
                 }
-                if self.io.borrow().gpu.state == GpuState::HDraw {
+                if self.io.gpu.state == GpuState::HDraw {
                     cycles += 1;
                 }
             }
             GAMEPAK_WS0_ADDR => match access.0 {
                 MemoryAccessType::NonSeq => match access.1 {
                     MemoryAccessWidth::MemoryAccess32 => {
-                        cycles += nonseq_cycles[self.ioregs.waitcnt.ws0_first_access() as usize];
+                        cycles += nonseq_cycles[self.io.waitcnt.ws0_first_access() as usize];
-                        cycles += seq_cycles[self.ioregs.waitcnt.ws0_second_access() as usize];
+                        cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize];
                     }
                     _ => {
-                        cycles += nonseq_cycles[self.ioregs.waitcnt.ws0_first_access() as usize];
+                        cycles += nonseq_cycles[self.io.waitcnt.ws0_first_access() as usize];
                     }
                 },
                 MemoryAccessType::Seq => {
-                    cycles += seq_cycles[self.ioregs.waitcnt.ws0_second_access() as usize];
+                    cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize];
                     if access.1 == MemoryAccessWidth::MemoryAccess32 {
-                        cycles += seq_cycles[self.ioregs.waitcnt.ws0_second_access() as usize];
+                        cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize];
                     }
                 }
             },

src/debugger/command.rs

@@ -6,7 +6,7 @@ use crate::core::GBAError;
 use crate::disass::Disassembler;
 
 use super::palette_view::create_palette_view;
-use super::tile_view::create_tile_view;
+// use super::tile_view::create_tile_view;
 use super::{parser::Value, Debugger, DebuggerError, DebuggerResult};
 
 use ansi_term::Colour;
@@ -32,7 +32,7 @@ pub enum Command {
     AddBreakpoint(Addr),
     DelBreakpoint(Addr),
     PaletteView,
-    TileView(u32),
+    // TileView(u32),
     ClearBreakpoints,
     ListBreakpoints,
     Reset,
@@ -44,7 +44,7 @@ impl Command {
         use Command::*;
         match *self {
             Info => println!("{}", debugger.gba.cpu),
-            DisplayInfo => println!("GPU: {:#?}", debugger.gba.io.borrow().gpu),
+            DisplayInfo => { /*println!("GPU: {:#?}", debugger.gba.sysbus.io.gpu)*/ }
             Step(count) => {
                 for _ in 0..count {
                     match debugger.gba.step() {
@@ -154,7 +154,7 @@ impl Command {
                 }
             }
             PaletteView => create_palette_view(&debugger.gba.sysbus.palette_ram.mem),
-            TileView(bg) => create_tile_view(bg, &debugger.gba),
+            // TileView(bg) => create_tile_view(bg, &debugger.gba),
             Reset => {
                 println!("resetting cpu...");
                 debugger.gba.cpu.reset(&mut debugger.gba.sysbus);
@@ -297,13 +297,13 @@ impl Debugger {
                 ))),
             },
             "palette-view" => Ok(Command::PaletteView),
-            "tiles" => {
+            // "tiles" => {
-                if args.len() != 1 {
+            //     if args.len() != 1 {
-                    return Err(DebuggerError::InvalidCommandFormat("tile <bg>".to_string()));
+            //         return Err(DebuggerError::InvalidCommandFormat("tile <bg>".to_string()));
-                }
+            //     }
-                let bg = self.val_number(&args[0])?;
+            //     let bg = self.val_number(&args[0])?;
-                Ok(Command::TileView(bg))
+            //     Ok(Command::TileView(bg))
-            }
+            // }
             "bl" => Ok(Command::ListBreakpoints),
             "q" | "quit" => Ok(Command::Quit),
             "r" | "reset" => Ok(Command::Reset),

src/debugger/tile_view.rs

@@ -1,107 +1,107 @@
-use std::time::Duration;
+// use std::time::Duration;
 
-use sdl2::event::Event;
+// use sdl2::event::Event;
-use sdl2::pixels::Color;
+// use sdl2::pixels::Color;
-use sdl2::rect::{Point, Rect};
+// use sdl2::rect::{Point, Rect};
-use sdl2::render::Canvas;
+// use sdl2::render::Canvas;
 
-use crate::core::gba::GameBoyAdvance;
+// use crate::core::gba::GameBoyAdvance;
-use crate::core::gpu::PixelFormat;
+// use crate::core::gpu::PixelFormat;
 
-fn draw_tile(
+// fn draw_tile(
-    gba: &GameBoyAdvance,
+//     gba: &GameBoyAdvance,
-    tile_addr: u32,
+//     tile_addr: u32,
-    pixel_format: PixelFormat,
+//     pixel_format: PixelFormat,
-    p: Point,
+//     p: Point,
-    canvas: &mut Canvas<sdl2::video::Window>,
+//     canvas: &mut Canvas<sdl2::video::Window>,
-) {
+// ) {
-    let io = gba.io.borrow();
+//     let io = &mut gba.sysbus.io;
-    for y in 0..8 {
+//     for y in 0..8 {
-        for x in 0..8 {
+//         for x in 0..8 {
-            let index = io
+//             let index = io
-                .gpu
+//                 .gpu
-                .read_pixel_index(&gba.sysbus, tile_addr, x, y, pixel_format);
+//                 .read_pixel_index(&gba.sysbus, tile_addr, x, y, pixel_format);
-            let color = io.gpu.get_palette_color(&gba.sysbus, index as u32, 0, 0);
+//             let color = io.gpu.get_palette_color(&gba.sysbus, index as u32, 0, 0);
-            canvas.set_draw_color(Color::RGB(
+//             canvas.set_draw_color(Color::RGB(
-                (color.r() as u8) << 3,
+//                 (color.r() as u8) << 3,
-                (color.g() as u8) << 3,
+//                 (color.g() as u8) << 3,
-                (color.b() as u8) << 3,
+//                 (color.b() as u8) << 3,
-            ));
+//             ));
-            canvas.draw_point(p.offset(x as i32, y as i32)).unwrap();
+//             canvas.draw_point(p.offset(x as i32, y as i32)).unwrap();
-        }
+//         }
-    }
+//     }
-}
+// }
 
-const TILESET_INITIAL_X: i32 = 0x20;
+// const TILESET_INITIAL_X: i32 = 0x20;
-const TILESET_INITIAL_Y: i32 = 0x20;
+// const TILESET_INITIAL_Y: i32 = 0x20;
 
-pub fn create_tile_view(bg: u32, gba: &GameBoyAdvance) {
+// pub fn create_tile_view(bg: u32, gba: &GameBoyAdvance) {
-    let sdl_context = sdl2::init().unwrap();
+//     let sdl_context = sdl2::init().unwrap();
-    let video_subsystem = sdl_context.video().unwrap();
+//     let video_subsystem = sdl_context.video().unwrap();
 
-    let window = video_subsystem
+//     let window = video_subsystem
-        .window("PaletteView", 512, 512)
+//         .window("PaletteView", 512, 512)
-        .position_centered()
+//         .position_centered()
-        .build()
+//         .build()
-        .unwrap();
+//         .unwrap();
 
-    let mut canvas = window.into_canvas().build().unwrap();
+//     let mut canvas = window.into_canvas().build().unwrap();
 
-    let bgcnt = gba.io.borrow().gpu.bg[bg as usize].bgcnt.clone();
+//     let bgcnt = gba.sysbus.io.gpu.bg[bg as usize].bgcnt.clone();
 
-    let (tile_size, pixel_format) = bgcnt.tile_format();
+//     let (tile_size, pixel_format) = bgcnt.tile_format();
-    let tileset_addr = bgcnt.char_block();
+//     let tileset_addr = bgcnt.char_block();
-    let tilemap_addr = bgcnt.screen_block();
+//     let tilemap_addr = bgcnt.screen_block();
-    let tiles_per_row = 32;
+//     let tiles_per_row = 32;
-    let num_tiles = 0x4000 / tile_size;
+//     let num_tiles = 0x4000 / tile_size;
-    println!("tileset: {:#x}, tilemap: {:#x}", tileset_addr, tilemap_addr);
+//     println!("tileset: {:#x}, tilemap: {:#x}", tileset_addr, tilemap_addr);
 
-    let mut event_pump = sdl_context.event_pump().unwrap();
+//     let mut event_pump = sdl_context.event_pump().unwrap();
-    'running: loop {
+//     'running: loop {
-        for event in event_pump.poll_iter() {
+//         for event in event_pump.poll_iter() {
-            match event {
+//             match event {
-                Event::Quit { .. } => break 'running,
+//                 Event::Quit { .. } => break 'running,
-                Event::MouseButtonDown { x, y, .. } => {
+//                 Event::MouseButtonDown { x, y, .. } => {
-                    let click_point = Point::new(x, y);
+//                     let click_point = Point::new(x, y);
-                    let mut tile_x = TILESET_INITIAL_X;
+//                     let mut tile_x = TILESET_INITIAL_X;
-                    let mut tile_y = TILESET_INITIAL_Y;
+//                     let mut tile_y = TILESET_INITIAL_Y;
-                    for t in 0..num_tiles {
+//                     for t in 0..num_tiles {
-                        let tile_addr = tileset_addr + t * tile_size;
+//                         let tile_addr = tileset_addr + t * tile_size;
-                        if t != 0 && t % tiles_per_row == 0 {
+//                         if t != 0 && t % tiles_per_row == 0 {
-                            tile_y += 10;
+//                             tile_y += 10;
-                            tile_x = TILESET_INITIAL_Y;
+//                             tile_x = TILESET_INITIAL_Y;
-                        }
+//                         }
-                        tile_x += 10;
+//                         tile_x += 10;
-                        if Rect::new(tile_x, tile_y, 8, 8).contains_point(click_point) {
+//                         if Rect::new(tile_x, tile_y, 8, 8).contains_point(click_point) {
-                            println!("tile #{:#x}, addr={:#x}", t, tile_addr);
+//                             println!("tile #{:#x}, addr={:#x}", t, tile_addr);
-                        }
+//                         }
-                    }
+//                     }
-                }
+//                 }
-                _ => {}
+//                 _ => {}
-            }
+//             }
-        }
+//         }
 
-        canvas.set_draw_color(Color::RGB(00, 00, 00));
+//         canvas.set_draw_color(Color::RGB(00, 00, 00));
-        canvas.clear();
+//         canvas.clear();
 
-        let mut tile_x = TILESET_INITIAL_X;
+//         let mut tile_x = TILESET_INITIAL_X;
-        let mut tile_y = TILESET_INITIAL_Y;
+//         let mut tile_y = TILESET_INITIAL_Y;
-        for t in 0..num_tiles {
+//         for t in 0..num_tiles {
-            let tile_addr = tileset_addr + t * tile_size;
+//             let tile_addr = tileset_addr + t * tile_size;
-            if t != 0 && t % tiles_per_row == 0 {
+//             if t != 0 && t % tiles_per_row == 0 {
-                tile_y += 10;
+//                 tile_y += 10;
-                tile_x = TILESET_INITIAL_Y;
+//                 tile_x = TILESET_INITIAL_Y;
-            }
+//             }
-            tile_x += 10;
+//             tile_x += 10;
-            draw_tile(
+//             draw_tile(
-                gba,
+//                 gba,
-                tile_addr,
+//                 tile_addr,
-                pixel_format,
+//                 pixel_format,
-                Point::from((tile_x, tile_y)),
+//                 Point::from((tile_x, tile_y)),
-                &mut canvas,
+//                 &mut canvas,
-            );
+//             );
-        }
+//         }
-        canvas.present();
+//         canvas.present();
-        ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
+//         ::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
-    }
+//     }
-}
+// }