fix xce, plp and cop instructions

snes-core/src/cpu/instructions/cop.rs

@@ -11,15 +11,22 @@ pub struct COP {}
 
 impl CPUInstruction for COP {
     fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
+        if !registers.emulation_mode {
             push_common::do_push(registers, bus, &[registers.pbr]);
+        }
         let (bytes, cycles) = cycles::increment_cycles_brk(registers.emulation_mode);
         registers.increment_pc(bytes); registers.cycles += cycles;
         push_common::do_push(registers, bus, &[(registers.pc >> 8) as u8, registers.pc as u8]);
         push_common::do_push(registers, bus, &[registers.p]);
         registers.set_irq_disable_flag(true);
         registers.pbr = 0x00;
+        if registers.emulation_mode {
+            let vector = (bus.read(0x00FFF4) as u16) | ((bus.read(0x00FFF5) as u16) << 8);
+            registers.pc = vector;
+        } else {
             let vector = (bus.read(0x00FFE4) as u16) | ((bus.read(0x00FFE5) as u16) << 8);
             registers.pc = vector;
+        }
         registers.set_decimal_mode_flag(false);
     }
 

snes-core/src/cpu/instructions/plp.rs

@@ -12,6 +12,10 @@ impl CPUInstruction for PLP {
     fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
         let bytes = pull_common::do_pull(registers, bus, 1, true);
         registers.p = bytes[0];
+        if registers.emulation_mode {
+            registers.set_memory_select_flag(true);
+            registers.set_index_register_select_flag(true);
+        }
         let (bytes, cycles) = cycles::increment_cycles_plp();
         registers.increment_pc(bytes); registers.cycles += cycles;
     }

snes-core/src/cpu/instructions/pull_common.rs

@@ -6,7 +6,11 @@ pub fn do_pull(registers: &mut Registers, bus: &mut Bus, count: usize, alter_fla
     let mut is_zero = true;
     for _ in 0..count {
         registers.increment_sp(1);
-        let byte = bus.read(registers.sp as u32);
+        let mut address = registers.sp;
+        if registers.emulation_mode {
+            address = (registers.sp | 0x100) & 0x1FF
+        }
+        let byte = bus.read(address as u32);
         if byte != 0 {
             is_zero = false;
         }

snes-core/src/cpu/instructions/push_common.rs

@@ -2,7 +2,10 @@ use crate::cpu::{registers::Registers, bus::Bus};
 
 pub fn do_push(registers: &mut Registers, bus: &mut Bus, bytes: &[u8]) {
     for byte in bytes {
-        let address = registers.sp as u32;
+        let mut address = registers.sp as u32;
+        if registers.emulation_mode {
+            address = (address & 0xFF) | 0x100;
+        }
         bus.write(address, *byte);
         registers.decrement_sp(1);
     }

snes-core/src/cpu/instructions/xce.rs

@@ -10,7 +10,12 @@ pub struct XCE {}
 
 impl CPUInstruction for XCE {
     fn execute(&self, registers: &mut Registers, _bus: &mut Bus) {
+        let did_mode_change = registers.emulation_mode != registers.get_carry_flag();
         registers.exchange_carry_and_emulation();
+        if did_mode_change {
+            registers.set_memory_select_flag(true);
+            registers.set_index_register_select_flag(true);
+        }
         let (bytes, cycles) = cycles::increment_cycles_exchange();
         registers.increment_pc(bytes); registers.cycles += cycles;
     }
@@ -34,5 +39,44 @@ mod cpu_instructions_tests {
         instruction.execute(&mut registers, &mut bus);
         assert_eq!(registers.pc, 0x0001);
         assert_eq!(registers.cycles, 2);
+        assert!(registers.get_memory_select_flag());
+        assert!(registers.get_index_register_select_flag());
+
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.pc = 0x0000;
+        registers.emulation_mode = true;
+        registers.set_carry_flag(false);
+        let instruction = XCE{};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.pc, 0x0001);
+        assert_eq!(registers.cycles, 2);
+        assert!(!registers.emulation_mode);
+        assert!(registers.get_memory_select_flag());
+        assert!(registers.get_index_register_select_flag());
+
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.pc = 0x0000;
+        registers.emulation_mode = false;
+        registers.set_carry_flag(true);
+        let instruction = XCE{};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.pc, 0x0001);
+        assert_eq!(registers.cycles, 2);
+        assert!(registers.emulation_mode);
+        assert!(registers.get_memory_select_flag());
+        assert!(registers.get_index_register_select_flag());
+
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.pc = 0x0000;
+        registers.emulation_mode = true;
+        registers.set_carry_flag(false);
+        let instruction = XCE{};
+        instruction.execute(&mut registers, &mut bus);
+        assert!(registers.get_carry_flag());
+        assert!(registers.get_memory_select_flag());
+        assert!(registers.get_index_register_select_flag());
     }
 }

snes-core/src/cpu/registers.rs

@@ -17,6 +17,34 @@ pub struct Registers {
     pub is_move_next: bool, // TODO: refactor these states with an enum
     pub cycles: usize,
 }
+/*
+P register flags
+
+Emulation mode:
+NV-BDIZC
+N - Negative
+V - Overflow
+-
+B - Break Instruction
+D - Decimal Mode
+I - IRQ Disable
+Z - Zero
+C - Carry
+
+Native Mode
+       E - Emulation Mode
+NVMXDIZC
+
+N - Negative
+V - Overflow
+M - Memory/Accumulator Select
+X - Index Register Select
+D - Decimal Mode
+I - IRQ Disable
+Z - Zero
+C - Carry
+
+*/
 
 impl Registers {
     pub fn new() -> Self {
@@ -214,7 +242,11 @@ impl Registers {
     }
 
     pub fn reset_rep_byte(&mut self, byte: u8) {
-        self.p &= !byte;
+        let mut effective_byte = byte;
+        if self.emulation_mode {
+            effective_byte &= 0b1100_1111;
+        }
+        self.p &= !effective_byte;
     }
 
     pub fn set_sep_byte(&mut self, byte: u8) {
@@ -440,6 +472,7 @@ mod registers_tests {
     #[test]
     fn test_reset_rep_byte() {
         let mut registers = Registers::new();
+        registers.emulation_mode = false;
         registers.p = 0xFF;
         registers.reset_rep_byte(0b0000_0001);
         assert_eq!(registers.p,  0b1111_1110);

snes-core/src/ppu/registers.rs

@@ -263,6 +263,16 @@ impl PPURegisters {
             0b11 => 128,
             _ => unreachable!(),
         };
+        let address_translation_rotate = match (register >> 2) & 0b11 {
+            0b00 => 0,
+            0b01 => 8,
+            0b10 => 9,
+            0b11 => 10,
+            _ => unreachable!(),
+        };
+        if address_translation_rotate > 0 {
+            // TODO: implement address translation
+        }
         let increment_when_lo = (register >> 7) != 1;
         let increment_when_hi = !increment_when_lo;
         let current_value = self.get_current_vram_address();

snes-cpu-test-runner/src/main.rs

@@ -116,7 +116,7 @@ fn main() -> Result<()> {
             emulator.tick();
         }
 
-        let is_emu_mode = emulator.cpu.registers.emulation_mode;
+        let is_emu_mode = emulator.cpu.registers.emulation_mode || (test.initial.e == 1);
         let is_16index = emulator.cpu.registers.is_16bit_index();
 
         let emu_mode_sp = (emulator.cpu.registers.sp as usize & 0xFF) | 0x100;