use std::fmt; use std::ops::Add; use super::cartridge::Cartridge; use super::gpu::{GpuState, VIDEO_RAM_SIZE}; use super::iodev::IoDevices; use super::{Addr, Bus}; const WORK_RAM_SIZE: usize = 256 * 1024; const INTERNAL_RAM_SIZE: usize = 32 * 1024; pub const BIOS_ADDR: u32 = 0x0000_0000; pub const EWRAM_ADDR: u32 = 0x0200_0000; pub const IWRAM_ADDR: u32 = 0x0300_0000; pub const IOMEM_ADDR: u32 = 0x0400_0000; pub const PALRAM_ADDR: u32 = 0x0500_0000; pub const VRAM_ADDR: u32 = 0x0600_0000; pub const OAM_ADDR: u32 = 0x0700_0000; pub const GAMEPAK_WS0_ADDR: u32 = 0x0800_0000; pub const GAMEPAK_MIRROR_WS0_ADDR: u32 = 0x0900_0000; pub const GAMEPAK_WS1_ADDR: u32 = 0x0A00_0000; pub const GAMEPAK_WS2_ADDR: u32 = 0x0C00_0000; #[derive(Debug, Copy, Clone)] pub enum MemoryAccessType { NonSeq, Seq, } impl fmt::Display for MemoryAccessType { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!( f, "{}", match self { MemoryAccessType::NonSeq => "N", MemoryAccessType::Seq => "S", } ) } } #[derive(Debug, PartialEq, Copy, Clone)] pub enum MemoryAccessWidth { MemoryAccess8, MemoryAccess16, MemoryAccess32, } impl Add for MemoryAccessType { type Output = MemoryAccess; fn add(self, other: MemoryAccessWidth) -> Self::Output { MemoryAccess(self, other) } } #[derive(Debug, Copy, Clone)] pub struct MemoryAccess(pub MemoryAccessType, pub MemoryAccessWidth); impl fmt::Display for MemoryAccess { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "{}-Cycle ({:?})", self.0, self.1) } } #[derive(Debug)] pub struct BoxedMemory { pub mem: Box<[u8]>, } impl BoxedMemory { pub fn new(boxed_slice: Box<[u8]>) -> BoxedMemory { BoxedMemory { mem: boxed_slice } } } impl Bus for BoxedMemory { fn read_8(&self, addr: Addr) -> u8 { self.mem[addr as usize] } fn write_8(&mut self, addr: Addr, value: u8) { self.mem[addr as usize] = value; } } #[derive(Debug)] struct DummyBus([u8; 4]); impl Bus for DummyBus { fn read_8(&self, _addr: Addr) -> u8 { 0 } fn write_8(&mut self, _addr: Addr, _value: u8) {} } pub struct SysBus { pub io: IoDevices, bios: BoxedMemory, onboard_work_ram: BoxedMemory, internal_work_ram: BoxedMemory, gamepak: Cartridge, dummy: DummyBus, pub trace_access: bool, } impl SysBus { pub fn new(io: IoDevices, bios_rom: Vec, gamepak: Cartridge) -> 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()), gamepak: gamepak, dummy: DummyBus([0; 4]), trace_access: false, } } fn map(&self, addr: Addr) -> (&dyn Bus, Addr) { let ofs = addr & 0x00ff_ffff; match addr & 0xff000000 { BIOS_ADDR => { if ofs >= 0x4000 { (&self.dummy, ofs) // TODO return last fetched opcode } else { (&self.bios, ofs) } } EWRAM_ADDR => (&self.onboard_work_ram, ofs & 0x3_ffff), IWRAM_ADDR => (&self.internal_work_ram, ofs & 0x7fff), IOMEM_ADDR => (&self.io, { if ofs & 0xffff == 0x8000 { 0x800 } else { ofs & 0x7ff } }), PALRAM_ADDR => (&self.io.gpu.palette_ram, ofs & 0x3ff), VRAM_ADDR => (&self.io.gpu.vram, { let mut ofs = ofs & ((VIDEO_RAM_SIZE as u32) - 1); if ofs > 0x18000 { ofs -= 0x8000; } ofs }), OAM_ADDR => (&self.io.gpu.oam, ofs & 0x3ff), GAMEPAK_WS0_ADDR | GAMEPAK_MIRROR_WS0_ADDR | GAMEPAK_WS1_ADDR | GAMEPAK_WS2_ADDR => { (&self.gamepak, addr & 0x01ff_ffff) } _ => (&self.dummy, ofs), } } /// TODO proc-macro for generating this function fn map_mut(&mut self, addr: Addr) -> (&mut dyn Bus, Addr) { let ofs = addr & 0x00ff_ffff; match addr & 0xff000000 { BIOS_ADDR => (&mut self.dummy, ofs), EWRAM_ADDR => (&mut self.onboard_work_ram, ofs & 0x3_ffff), IWRAM_ADDR => (&mut self.internal_work_ram, ofs & 0x7fff), IOMEM_ADDR => (&mut self.io, { if ofs & 0xffff == 0x8000 { 0x800 } else { ofs & 0x7ff } }), PALRAM_ADDR => (&mut self.io.gpu.palette_ram, ofs & 0x3ff), VRAM_ADDR => (&mut self.io.gpu.vram, { let mut ofs = ofs & ((VIDEO_RAM_SIZE as u32) - 1); if ofs > 0x18000 { ofs -= 0x8000; } ofs }), OAM_ADDR => (&mut self.io.gpu.oam, ofs & 0x3ff), GAMEPAK_WS0_ADDR | GAMEPAK_MIRROR_WS0_ADDR | GAMEPAK_WS1_ADDR | GAMEPAK_WS2_ADDR => { (&mut self.gamepak, addr & 0x01ff_ffff) } _ => (&mut self.dummy, ofs), } } pub fn get_cycles(&self, addr: Addr, access: MemoryAccess) -> usize { let nonseq_cycles = [4, 3, 2, 8]; let seq_cycles = [2, 1]; let mut cycles = 0; // TODO handle EWRAM accesses match addr & 0xff000000 { EWRAM_ADDR => match access.1 { MemoryAccessWidth::MemoryAccess32 => cycles += 6, _ => cycles += 3, }, OAM_ADDR | VRAM_ADDR | PALRAM_ADDR => { match access.1 { MemoryAccessWidth::MemoryAccess32 => cycles += 2, _ => cycles += 1, } if self.io.gpu.state == GpuState::HDraw { cycles += 1; } } GAMEPAK_WS0_ADDR | GAMEPAK_MIRROR_WS0_ADDR => match access.0 { MemoryAccessType::NonSeq => match access.1 { MemoryAccessWidth::MemoryAccess32 => { cycles += nonseq_cycles[self.io.waitcnt.ws0_first_access() as usize]; cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize]; } _ => { cycles += nonseq_cycles[self.io.waitcnt.ws0_first_access() as usize]; } }, MemoryAccessType::Seq => { cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize]; if access.1 == MemoryAccessWidth::MemoryAccess32 { cycles += seq_cycles[self.io.waitcnt.ws0_second_access() as usize]; } } }, GAMEPAK_WS1_ADDR | GAMEPAK_WS2_ADDR => { panic!("unimplemented - need to refactor code with a nice macro :(") } _ => {} } cycles } } impl Bus for SysBus { fn read_32(&self, addr: Addr) -> u32 { let (dev, addr) = self.map(addr); dev.read_32(addr & 0x1ff_fffc) } fn read_16(&self, addr: Addr) -> u16 { let (dev, addr) = self.map(addr); dev.read_16(addr & 0x1ff_fffe) } fn read_8(&self, addr: Addr) -> u8 { let (dev, addr) = self.map(addr); dev.read_8(addr & 0x1ff_ffff) } fn write_32(&mut self, addr: Addr, value: u32) { let (dev, addr) = self.map_mut(addr); dev.write_32(addr & 0x1ff_fffc, value); } fn write_16(&mut self, addr: Addr, value: u16) { let (dev, addr) = self.map_mut(addr); dev.write_16(addr & 0x1ff_fffe, value); } fn write_8(&mut self, addr: Addr, value: u8) { let (dev, addr) = self.map_mut(addr); dev.write_8(addr & 0x1ff_ffff, value); } }