diff --git a/snes-core/src/cpu/instructionstemp/mod.rs b/snes-core/src/cpu/instructionstemp/mod.rs index add0fbf..ff1d304 100644 --- a/snes-core/src/cpu/instructionstemp/mod.rs +++ b/snes-core/src/cpu/instructionstemp/mod.rs @@ -64,6 +64,7 @@ pub mod ror; pub mod rti; pub mod rtl; pub mod rts; +pub mod sbc; pub mod bit_common; pub mod dec_common; pub mod decoder_common; diff --git a/snes-core/src/cpu/instructionstemp/sbc.rs b/snes-core/src/cpu/instructionstemp/sbc.rs new file mode 100644 index 0000000..71c4b7d --- /dev/null +++ b/snes-core/src/cpu/instructionstemp/sbc.rs @@ -0,0 +1,187 @@ +use crate::{cpu::{bus::Bus, registers::Registers}, utils::{alu, addressing::AddressingMode}}; + +use crate::cpu::cycles; +use super::{CPUInstruction, Decode, read_8bit_from_address, read_16bit_from_address}; +use super::decoder_common; + +static INSTR_NAME: &'static str = "SBC"; + +pub struct SBC8BIN { + addressing_mode: AddressingMode, +} + +impl CPUInstruction for SBC8BIN { + fn execute(&self, registers: &mut Registers, bus: &mut Bus) { + let (result, affected_flags) = alu::sbc_bin( + registers.a as u8, + read_8bit_from_address(registers, bus, self.addressing_mode), + registers.get_carry_flag(), + ); + registers.set_low_a(result); + registers.set_flags(&affected_flags); + let (bytes, cycles) = cycles::increment_cycles_arithmetic(®isters, self.addressing_mode); + registers.increment_pc(bytes); registers.cycles += cycles; + } +} + +impl Decode for SBC8BIN { + 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 SBC16BIN { + addressing_mode: AddressingMode, +} + +impl CPUInstruction for SBC16BIN { + fn execute(&self, registers: &mut Registers, bus: &mut Bus) { + let (result, affected_flags) = alu::sbc_bin( + registers.a, + read_16bit_from_address(registers, bus, self.addressing_mode), + registers.get_carry_flag(), + ); + registers.a = result; + registers.set_flags(&affected_flags); + let (bytes, cycles) = cycles::increment_cycles_arithmetic(®isters, self.addressing_mode); + registers.increment_pc(bytes); registers.cycles += cycles; + } +} + +impl Decode for SBC16BIN { + fn mnemonic(&self, registers: &Registers, bus: &Bus, opcode: u8) -> String { + decoder_common::mnemonic_arithmetic(true, opcode, INSTR_NAME, self.addressing_mode, registers, bus) + } +} + +pub struct SBC8BCD { + addressing_mode: AddressingMode, +} + +impl CPUInstruction for SBC8BCD { + fn execute(&self, registers: &mut Registers, bus: &mut Bus) { + let (result, affected_flags) = alu::sbc_bcd( + registers.a as u8, + read_8bit_from_address(registers, bus, self.addressing_mode), + registers.get_carry_flag(), + ); + registers.set_low_a(result); + registers.set_flags(&affected_flags); + let (bytes, cycles) = cycles::increment_cycles_arithmetic(®isters, self.addressing_mode); + registers.increment_pc(bytes); registers.cycles += cycles; + } +} + +impl Decode for SBC8BCD { + 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 SBC16BCD { + addressing_mode: AddressingMode, +} + +impl CPUInstruction for SBC16BCD { + fn execute(&self, registers: &mut Registers, bus: &mut Bus) { + let (result, affected_flags) = alu::sbc_bcd( + registers.a, + read_16bit_from_address(registers, bus, self.addressing_mode), + registers.get_carry_flag(), + ); + registers.a = result; + registers.set_flags(&affected_flags); + let (bytes, cycles) = cycles::increment_cycles_arithmetic(®isters, self.addressing_mode); + registers.increment_pc(bytes); registers.cycles += cycles; + } +} + +impl Decode for SBC16BCD { + 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_sbc_bin_8bit() { + let mut registers = Registers::new(); + let mut bus = Bus::new(); + registers.emulation_mode = false; + registers.a = 0x0040; + registers.pbr = 0x00; + registers.pc = 0x0000; + registers.set_memory_select_flag(true); + bus.write(0x000001, 0x40); + let instruction = SBC8BIN{addressing_mode: AddressingMode::Immediate}; + instruction.execute(&mut registers, &mut bus); + assert_eq!(registers.a, 0x00); + assert_eq!(registers.pc, 0x02); + assert_eq!(registers.cycles, 2); + assert!(registers.get_zero_flag()); + assert!(!registers.get_carry_flag()); + } + + #[test] + fn test_sbc_bin_16bit() { + let mut registers = Registers::new(); + let mut bus = Bus::new(); + registers.emulation_mode = false; + registers.a = 0x4000; + registers.pbr = 0x00; + registers.pc = 0x0000; + registers.set_memory_select_flag(false); + bus.write(0x000001, 0x00); + bus.write(0x000002, 0x40); + let instruction = SBC16BIN{addressing_mode: AddressingMode::Immediate}; + instruction.execute(&mut registers, &mut bus); + assert_eq!(registers.a, 0x0000); + assert_eq!(registers.pc, 0x03); + assert_eq!(registers.cycles, 3); + assert!(registers.get_zero_flag()); + assert!(!registers.get_carry_flag()); + } + + #[test] + fn test_sbc_bcd_8bit() { + let mut registers = Registers::new(); + let mut bus = Bus::new(); + registers.emulation_mode = false; + registers.a = 0x0049; + registers.pbr = 0x00; + registers.pc = 0x0000; + registers.set_16bit_mode(false); + bus.write(0x000001, 0x48); + let instruction = SBC8BCD{addressing_mode: AddressingMode::Immediate}; + instruction.execute(&mut registers, &mut bus); + assert_eq!(registers.a, 0x00); + assert_eq!(registers.pc, 0x02); + assert_eq!(registers.cycles, 2); + assert!(registers.get_zero_flag()); + assert!(registers.get_carry_flag()); + } + + #[test] + fn test_sbc_bcd_16bit() { + let mut registers = Registers::new(); + let mut bus = Bus::new(); + registers.emulation_mode = false; + registers.a = 0x0049; + registers.pbr = 0x00; + registers.pc = 0x0000; + registers.set_16bit_mode(true); + bus.write(0x000001, 0x48); + bus.write(0x000002, 0x00); + let instruction = SBC16BCD{addressing_mode: AddressingMode::Immediate}; + instruction.execute(&mut registers, &mut bus); + assert_eq!(registers.a, 0x0000); + assert_eq!(registers.pc, 0x03); + assert_eq!(registers.cycles, 3); + assert!(registers.get_zero_flag()); + assert!(registers.get_carry_flag()); + } +}