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Sam M W 2024-04-23 17:07:16 +01:00 committed by Matthias Endler
parent 97d6b3fd89
commit ad622bc930
1 changed files with 19 additions and 7 deletions
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26
src/cpu.rs
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@ -32,7 +32,6 @@ use crate::Variant;
use crate::registers::{Registers, StackPointer, Status, StatusArgs}; use crate::registers::{Registers, StackPointer, Status, StatusArgs};
fn address_from_bytes(lo: u8, hi: u8) -> u16 { fn address_from_bytes(lo: u8, hi: u8) -> u16 {
u16::from(lo) + (u16::from(hi) << 8usize) u16::from(lo) + (u16::from(hi) << 8usize)
} }
@ -140,12 +139,16 @@ impl<M: Bus, V: Variant> CPU<M, V> {
AddressingMode::AbsoluteX => { AddressingMode::AbsoluteX => {
// Use [u8, ..2] from instruction as address, add X // Use [u8, ..2] from instruction as address, add X
// (Output: a 16-bit address) // (Output: a 16-bit address)
OpInput::UseAddress(address_from_bytes(slice[0], slice[1]).wrapping_add(x.into())) OpInput::UseAddress(
address_from_bytes(slice[0], slice[1]).wrapping_add(x.into()),
)
} }
AddressingMode::AbsoluteY => { AddressingMode::AbsoluteY => {
// Use [u8, ..2] from instruction as address, add Y // Use [u8, ..2] from instruction as address, add Y
// (Output: a 16-bit address) // (Output: a 16-bit address)
OpInput::UseAddress(address_from_bytes(slice[0], slice[1]).wrapping_add(y.into())) OpInput::UseAddress(
address_from_bytes(slice[0], slice[1]).wrapping_add(y.into()),
)
} }
AddressingMode::IndirectWithFix => { AddressingMode::IndirectWithFix => {
// Use [u8, ..2] from instruction as an address. Interpret the // Use [u8, ..2] from instruction as an address. Interpret the
@ -165,11 +168,18 @@ impl<M: Bus, V: Variant> CPU<M, V> {
let low_byte_of_target = memory.get_byte(pointer); let low_byte_of_target = memory.get_byte(pointer);
let low_byte_of_incremented_pointer = pointer.to_le_bytes()[0].wrapping_add(1); let low_byte_of_incremented_pointer =
let incremented_pointer = u16::from_le_bytes([low_byte_of_incremented_pointer, pointer.to_le_bytes()[1]]); pointer.to_le_bytes()[0].wrapping_add(1);
let incremented_pointer = u16::from_le_bytes([
low_byte_of_incremented_pointer,
pointer.to_le_bytes()[1],
]);
let high_byte_of_target = memory.get_byte(incremented_pointer); let high_byte_of_target = memory.get_byte(incremented_pointer);
OpInput::UseAddress(address_from_bytes(low_byte_of_target, high_byte_of_target)) OpInput::UseAddress(address_from_bytes(
low_byte_of_target,
high_byte_of_target,
))
} }
AddressingMode::IndexedIndirectX => { AddressingMode::IndexedIndirectX => {
// Use [u8, ..1] from instruction // Use [u8, ..1] from instruction
@ -187,7 +197,9 @@ impl<M: Bus, V: Variant> CPU<M, V> {
// (Output: a 16-bit address) // (Output: a 16-bit address)
let start = slice[0]; let start = slice[0];
let slice = read_address(memory, u16::from(start)); let slice = read_address(memory, u16::from(start));
OpInput::UseAddress(address_from_bytes(slice[0], slice[1]).wrapping_add(y.into())) OpInput::UseAddress(
address_from_bytes(slice[0], slice[1]).wrapping_add(y.into()),
)
} }
}; };