FranLMSP/snes
1
0
Fork 0
mirror of https://github.com/FranLMSP/snes.git synced 2026-08-03 08:30:01 -04:00
Code Issues Packages Projects Releases Wiki Activity

Small refactor to cycles module

Browse Source
This commit is contained in:
Franco Colmenarez
2022-11-21 19:06:26 -05:00
parent 89a81917e0
commit cc9968dd93
1 changed files with 34 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files
snes-core/src/cpu/cycles.rs
+34 -42
View File
@@ -25,7 +25,7 @@ const BITWISE_CONDITIONS: [Condition; 3] = [
];
impl CPU {
fn common_conditions(&mut self, addressing_mode: AddressingMode, conditions: &[Condition]) {
fn common_conditions(&mut self, addressing_mode: AddressingMode, conditions: &[Condition]) -> (u16, usize) {
let mut bytes = 0;
let mut cycles = 0;
@@ -80,8 +80,7 @@ impl CPU {
};
}
self.registers.increment_pc(bytes);
self.cycles += cycles;
(bytes, cycles)
}
fn common_bytes_cycles_arithmetic(addressing_mode: AddressingMode) -> (u16, usize) {
@@ -122,30 +121,30 @@ impl CPU {
pub fn increment_cycles_arithmetic(&mut self, addressing_mode: AddressingMode) {
let (bytes, cycles) = CPU::common_bytes_cycles_arithmetic(addressing_mode);
self.registers.increment_pc(bytes);
self.cycles += cycles;
self.common_conditions(addressing_mode, &ALL_CONDITIONS);
self.registers.increment_pc(bytes); self.cycles += cycles;
let (bytes, cycles) = self.common_conditions(addressing_mode, &ALL_CONDITIONS);
self.registers.increment_pc(bytes); self.cycles += cycles;
}
pub fn increment_cycles_bitwise(&mut self, addressing_mode: AddressingMode) {
let (bytes, cycles) = CPU::common_bytes_cycles_arithmetic(addressing_mode);
self.registers.increment_pc(bytes);
self.cycles += cycles;
self.common_conditions(addressing_mode, &BITWISE_CONDITIONS);
self.registers.increment_pc(bytes); self.cycles += cycles;
let (bytes, cycles) = self.common_conditions(addressing_mode, &BITWISE_CONDITIONS);
self.registers.increment_pc(bytes); self.cycles += cycles;
}
pub fn increment_cycles_shift(&mut self, addressing_mode: AddressingMode) {
let (bytes, cycles) = CPU::common_bytes_cycles_shift(addressing_mode);
self.registers.increment_pc(bytes);
self.cycles += cycles;
self.registers.increment_pc(bytes); self.cycles += cycles;
// Add 2 cycles if m = 1
// TODO: Consider that this may be adding one byte more
self.common_conditions(addressing_mode, &[Condition::MemorySelectFlag]);
self.common_conditions(addressing_mode, &[
let (_, cycles) = self.common_conditions(addressing_mode, &[Condition::MemorySelectFlag]);
self.cycles += cycles;
let (bytes, cycles) = self.common_conditions(addressing_mode, &[
Condition::MemorySelectFlag,
Condition::DirectPageZero,
Condition::IndexCrossesPageBoundary,
]);
self.registers.increment_pc(bytes); self.cycles += cycles;
}
}
@@ -159,66 +158,59 @@ mod cpu_instructions_tests {
// 16-bit Memory/accumulator flag condition
cpu.registers.pc = 0;
cpu.cycles = 0;
cpu.registers.set_decimal_mode_flag(false);
cpu.registers.set_16bit_mode(false);
cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 0);
assert_eq!(cpu.cycles, 0);
let (bytes, cycles) = cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(bytes, 0);
assert_eq!(cycles, 0);
cpu.registers.pc = 0;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(true);
cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 1);
assert_eq!(cpu.cycles, 1);
let (bytes, cycles) = cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(bytes, 1);
assert_eq!(cycles, 1);
// Decimal flag condition
cpu.registers.pc = 0;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(true);
cpu.registers.set_decimal_mode_flag(true);
cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 1);
assert_eq!(cpu.cycles, 2);
let (bytes, cycles) = cpu.common_conditions(AddressingMode::Immediate, &ALL_CONDITIONS);
assert_eq!(bytes, 1);
assert_eq!(cycles, 2);
// Low byte of direct page register other than zero condition
cpu.registers.pc = 0;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(false);
cpu.registers.set_decimal_mode_flag(false);
cpu.registers.d = 0x0000;
cpu.common_conditions(AddressingMode::DirectPage, &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 0);
assert_eq!(cpu.cycles, 0);
let (bytes, cycles) = cpu.common_conditions(AddressingMode::DirectPage, &ALL_CONDITIONS);
assert_eq!(bytes, 0);
assert_eq!(cycles, 0);
cpu.registers.pc = 0;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(false);
cpu.registers.set_decimal_mode_flag(false);
cpu.registers.d = 0x0001;
cpu.common_conditions(AddressingMode::DirectPage, &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 0);
assert_eq!(cpu.cycles, 1);
let (bytes, cycles) = cpu.common_conditions(AddressingMode::DirectPage, &ALL_CONDITIONS);
assert_eq!(bytes, 0);
assert_eq!(cycles, 1);
// Adding index crosses a page boundary condition
cpu.registers.pc = 0xFE;
cpu.registers.x = 0x0001;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(false);
cpu.registers.set_decimal_mode_flag(false);
cpu.common_conditions(AddressingMode::AbsoluteIndexed(IndexRegister::X), &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 0xFE);
assert_eq!(cpu.cycles, 0); // Doesn't cross boundary
let (bytes, cycles) = cpu.common_conditions(AddressingMode::AbsoluteIndexed(IndexRegister::X), &ALL_CONDITIONS);
assert_eq!(bytes, 0);
assert_eq!(cycles, 0); // Doesn't cross boundary
cpu.registers.pc = 0xFE;
cpu.registers.x = 0x0010;
cpu.cycles = 0;
cpu.registers.set_16bit_mode(false);
cpu.registers.set_decimal_mode_flag(false);
cpu.common_conditions(AddressingMode::AbsoluteIndexed(IndexRegister::X), &ALL_CONDITIONS);
assert_eq!(cpu.registers.pc, 0xFE);
assert_eq!(cpu.cycles, 1); // Crosses boundary
let (bytes, cycles) = cpu.common_conditions(AddressingMode::AbsoluteIndexed(IndexRegister::X), &ALL_CONDITIONS);
assert_eq!(bytes, 0);
assert_eq!(cycles, 1); // Crosses boundary
// Test common and aritmetic together
cpu.registers.pc = 0xF5;