FranLMSP/snes
1
0
Fork 0
mirror of https://github.com/FranLMSP/snes.git synced 2026-01-01 07:21:35 -05:00
Code Issues Packages Projects Releases Wiki Activity

Minor fixes with addressing modes and ldy instr

Browse Source
This commit is contained in:
Franco Colmenarez
2024-01-29 21:44:47 -05:00
parent 467ffd791e
commit 48309a0021
7 changed files with 20 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
snes-core/src/cpu/cycles.rs
View File

@@ -96,7 +96,7 @@ fn common_conditions(cpu_registers: &Registers, addressing_mode: AddressingMode,
},
// Add 1 byte if <index> = 0 (16-bit index registers)
Condition::IndexIs16Bit => {
if cpu_registers.is_16bit_index() {
if addressing_mode == AddressingMode::Immediate && cpu_registers.is_16bit_index() {
bytes += 1; cycles += 1;
}
},

5
snes-core/src/cpu/instructions/lda.rs
View File

@@ -4,7 +4,7 @@ use crate::cpu::{bus::Bus, registers::Registers};
use crate::utils::addressing::AddressingMode;
use super::read_write_common::{read_8bit_from_address, read_16bit_from_address};
use super::{CPUInstruction, bit_common};
use super::CPUInstruction;
use super::decoder_common;
static INSTR_NAME: &str = "LDA";
@@ -41,12 +41,11 @@ pub struct LDA8 {
impl CPUInstruction for LDA8 {
fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
let value = read_8bit_from_address(registers, bus, self.addressing_mode);
registers.set_low_a(value);
registers.set_flags(&[
Flags::Negative(value >> 7 == 1),
Flags::Zero(value == 0),
]);
registers.set_low_a(value);
bit_common::do_bit(registers, registers.a as u8, value, self.addressing_mode);
let (bytes, cycles) = cycles::increment_cycles_lda(registers, self.addressing_mode);
registers.increment_pc(bytes); registers.cycles += cycles;
}

5
snes-core/src/cpu/instructions/ldx.rs
View File

@@ -4,7 +4,7 @@ use crate::cpu::{bus::Bus, registers::Registers};
use crate::utils::addressing::AddressingMode;
use super::read_write_common::{read_8bit_from_address, read_16bit_from_address};
use super::{CPUInstruction, bit_common};
use super::CPUInstruction;
use super::decoder_common;
static INSTR_NAME: &str = "LDX";
@@ -41,12 +41,11 @@ pub struct LDX8 {
impl CPUInstruction for LDX8 {
fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
let value = read_8bit_from_address(registers, bus, self.addressing_mode);
registers.set_low_x(value);
registers.set_flags(&[
Flags::Negative(value >> 7 == 1),
Flags::Zero(value == 0),
]);
registers.set_low_x(value);
bit_common::do_bit(registers, registers.x as u8, value, self.addressing_mode);
let (bytes, cycles) = cycles::increment_cycles_ld_index(registers, self.addressing_mode);
registers.increment_pc(bytes); registers.cycles += cycles;
}

5
snes-core/src/cpu/instructions/ldy.rs
View File

@@ -4,7 +4,7 @@ use crate::cpu::{bus::Bus, registers::Registers};
use crate::utils::addressing::AddressingMode;
use super::read_write_common::{read_8bit_from_address, read_16bit_from_address};
use super::{CPUInstruction, bit_common};
use super::CPUInstruction;
use super::decoder_common;
static INSTR_NAME: &str = "LDY";
@@ -41,12 +41,11 @@ pub struct LDY8 {
impl CPUInstruction for LDY8 {
fn execute(&self, registers: &mut Registers, bus: &mut Bus) {
let value = read_8bit_from_address(registers, bus, self.addressing_mode);
registers.set_low_y(value);
registers.set_flags(&[
Flags::Negative(value >> 7 == 1),
Flags::Zero(value == 0),
]);
registers.set_low_y(value);
bit_common::do_bit(registers, registers.y as u8, value, self.addressing_mode);
let (bytes, cycles) = cycles::increment_cycles_ld_index(registers, self.addressing_mode);
registers.increment_pc(bytes); registers.cycles += cycles;
}

4
snes-core/src/cpu/instructions/mapper.rs
View File

@@ -178,8 +178,8 @@ pub fn map_opcode_to_instruction(opcode: u8) -> Box<dyn CPUInstruction> {
0xA0 => Box::new(LDY{addressing_mode: A::Immediate}),
0xAC => Box::new(LDY{addressing_mode: A::Absolute}),
0xA4 => Box::new(LDY{addressing_mode: A::DirectPage}),
0xB4 => Box::new(LDY{addressing_mode: A::AbsoluteIndexed(I::Y)}),
0xBC => Box::new(LDY{addressing_mode: A::DirectPageIndexed(I::Y)}),
0xBC => Box::new(LDY{addressing_mode: A::AbsoluteIndexed(I::X)}),
0xB4 => Box::new(LDY{addressing_mode: A::DirectPageIndexed(I::X)}),
// LSR
0x4A => Box::new(LSR{addressing_mode: A::Accumulator}),
0x4E => Box::new(LSR{addressing_mode: A::Absolute}),

2
snes-core/src/rom/special_ram_cart.rs
View File

@@ -7,7 +7,7 @@ pub struct SpecialRAMCart {
impl SpecialRAMCart {
pub fn new() -> Self {
Self {
data: vec![0x00; 0x1000000],
data: vec![0x00; 0x100000000],
}
}
}

13
snes-core/src/utils/addressing.rs
View File

@@ -21,7 +21,12 @@ pub fn immediate(pc_addr: u32) -> u32 {
/// OPCODE addr
pub fn absolute(bus: &mut Bus, pc_addr: u32, dbr: u8) -> u32 {
let addr = (bus.read(pc_addr + 1) as u32) | ((bus.read(pc_addr + 2) as u32) << 8);
let pbr = pc_addr & 0xFF0000;
let bus_addr_1 = pbr | ((pc_addr as u16).wrapping_add(1) as u32);
let bus_addr_2 = pbr | ((pc_addr as u16).wrapping_add(2) as u32);
let addr =
(bus.read(bus_addr_1) as u32) |
((bus.read(bus_addr_2) as u32) << 8);
((dbr as u32) << 16) | addr
}
@@ -49,7 +54,9 @@ pub fn absolute_indirect_long(bus: &mut Bus, pc_addr: u32, dbr: u8) -> u32 {
/// OPCODE dp
pub fn direct_page(bus: &mut Bus, pc_addr: u32, direct_page_register: u16) -> u32 {
(bus.read(pc_addr + 1) as u16).wrapping_add(direct_page_register) as u32
let pbr = pc_addr & 0xFF0000;
let bus_addr = pbr | ((pc_addr as u16).wrapping_add(1) as u32);
(bus.read(bus_addr) as u16).wrapping_add(direct_page_register) as u32
}
/// OPCODE (dp)
@@ -142,7 +149,7 @@ impl Display for IndexRegister {
}
}
#[derive(Copy, Clone)]
#[derive(Copy, Clone, PartialEq)]
pub enum AddressingMode {
Accumulator,
Immediate,