lsr

snes-core/src/cpu/instructionstemp/lsr.rs

@@ -0,0 +1,131 @@
+use crate::{cpu::{bus::Bus, registers::Registers}, utils::{alu, addressing::AddressingMode}};
+
+use crate::cpu::cycles;
+use super::{CPUInstruction, Decode, read_8bit_from_address, write_8bit_to_address, read_16bit_from_address, write_16bit_to_address};
+use super::decoder_common;
+
+static INSTR_NAME: &'static str = "LSR";
+
+pub struct LSR8 {
+    addressing_mode: AddressingMode,
+}
+
+impl CPUInstruction for LSR8 {
+    fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
+        let (result, affected_flags) = alu::lsr(read_8bit_from_address(registers, bus, self.addressing_mode));
+        write_8bit_to_address(registers, bus, self.addressing_mode, result);
+        registers.set_flags(&affected_flags);
+        let (bytes, cycles) = cycles::increment_cycles_shift(&registers, self.addressing_mode);
+        registers.increment_pc(bytes); registers.cycles += cycles;
+    }
+}
+
+impl Decode for LSR8 {
+    fn mnemonic(&self, registers: &Registers, bus: &Bus, opcode: u8) -> String {
+        decoder_common::mnemonic_arithmetic(false, opcode, INSTR_NAME, self.addressing_mode, registers, bus)
+    }
+}
+
+pub struct LSR16 {
+    addressing_mode: AddressingMode,
+}
+
+impl CPUInstruction for LSR16 {
+    fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
+        let (result, affected_flags) = alu::lsr(read_16bit_from_address(registers, bus, self.addressing_mode));
+        write_16bit_to_address(registers, bus, self.addressing_mode, result);
+        registers.set_flags(&affected_flags);
+        let (bytes, cycles) = cycles::increment_cycles_shift(&registers, self.addressing_mode);
+        registers.increment_pc(bytes); registers.cycles += cycles;
+    }
+}
+
+impl Decode for LSR16 {
+    fn mnemonic(&self, registers: &Registers, bus: &Bus, opcode: u8) -> String {
+        decoder_common::mnemonic_arithmetic(true, opcode, INSTR_NAME, self.addressing_mode, registers, bus)
+    }
+}
+
+
+#[cfg(test)]
+mod cpu_instructions_tests {
+    use super::*;
+
+    #[test]
+    fn test_8bit() {
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.emulation_mode = false;
+        registers.a   = 0b00000000_00000011;
+        registers.pbr = 0x00;
+        registers.pc  = 0x0000;
+        registers.set_16bit_mode(false);
+        registers.set_negative_flag(true);
+        registers.set_carry_flag(false);
+        let instruction = LSR8{addressing_mode: AddressingMode::Accumulator};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.a, 0b00000000_00000001);
+        assert_eq!(registers.pc, 0x01);
+        assert_eq!(registers.cycles, 2);
+        assert!(registers.get_carry_flag());
+        assert!(!registers.get_zero_flag());
+        assert!(!registers.get_negative_flag());
+
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.emulation_mode = false;
+        registers.a   = 0b00000001_10000011;
+        registers.pbr = 0x00;
+        registers.pc  = 0x0000;
+        registers.set_16bit_mode(false);
+        registers.set_negative_flag(true);
+        registers.set_carry_flag(false);
+        let instruction = LSR8{addressing_mode: AddressingMode::Accumulator};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.a, 0b00000001_01000001);
+        assert_eq!(registers.pc, 0x01);
+        assert_eq!(registers.cycles, 2);
+        assert!(registers.get_carry_flag());
+        assert!(!registers.get_zero_flag());
+        assert!(!registers.get_negative_flag());
+    }
+
+    #[test]
+    fn test_16bit() {
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.emulation_mode = false;
+        registers.a   = 0b00000000_00000011;
+        registers.pbr = 0x00;
+        registers.pc  = 0x0000;
+        registers.set_16bit_mode(true);
+        registers.set_negative_flag(true);
+        registers.set_carry_flag(false);
+        let instruction = LSR16{addressing_mode: AddressingMode::Accumulator};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.a, 0b00000000_00000001);
+        assert_eq!(registers.pc, 0x01);
+        assert_eq!(registers.cycles, 4);
+        assert!(registers.get_carry_flag());
+        assert!(!registers.get_zero_flag());
+        assert!(!registers.get_negative_flag());
+
+        let mut registers = Registers::new();
+        let mut bus = Bus::new();
+        registers.emulation_mode = false;
+        registers.a   = 0b10000000_00000011;
+        registers.pbr = 0x00;
+        registers.pc  = 0x0000;
+        registers.set_16bit_mode(true);
+        registers.set_negative_flag(true);
+        registers.set_carry_flag(true);
+        let instruction = LSR16{addressing_mode: AddressingMode::Accumulator};
+        instruction.execute(&mut registers, &mut bus);
+        assert_eq!(registers.a, 0b01000000_00000001);
+        assert_eq!(registers.pc, 0x01);
+        assert_eq!(registers.cycles, 4);
+        assert!(registers.get_carry_flag());
+        assert!(!registers.get_zero_flag());
+        assert!(!registers.get_negative_flag());
+    }
+}

snes-core/src/cpu/instructionstemp/mod.rs

@@ -37,6 +37,7 @@ pub mod jsr;
 pub mod lda;
 pub mod ldx;
 pub mod ldy;
+pub mod lsr;
 pub mod bit_common;
 pub mod dec_common;
 pub mod decoder_common;