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fix stack relative addressing mode

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This commit is contained in:
Franco Colmenarez
2024-03-10 19:06:06 -05:00
parent b8cfc55fb9
commit 59a3ca286a
1 changed files with 8 additions and 9 deletions
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17
snes-core/src/utils/addressing.rs
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@@ -118,8 +118,9 @@ pub fn direct_page_indirect_long_indexed(bus: &mut Bus, pc_addr: u32, direct_pag
}
/// OPCODE sr,S
pub fn stack_relative(bus: &mut Bus, pc_addr: u32, stack_pointer: u16, dbr: u8) -> u32 {
absolute_indexed(bus, pc_addr, stack_pointer, dbr) & 0xFFFF
pub fn stack_relative(bus: &mut Bus, pc_addr: u32, stack_pointer: u16) -> u32 {
let operand = bus.read(pc_addr + 1);
stack_pointer.wrapping_add(operand as u16) as u32
}
/// OPCODE (sr,S),X
@@ -193,7 +194,7 @@ impl AddressingMode {
Self::DirectPageIndexedIndirect(idx) => direct_page_indexed_indirect(bus, p.pc_addr, p.direct_page_register, if idx == X {p.x} else {p.y}, p.dbr),
Self::DirectPageIndirectIndexed(idx) => direct_page_indirect_indexed(bus, p.pc_addr, p.direct_page_register, if idx == X {p.x} else {p.y}, p.dbr),
Self::DirectPageIndirectLongIndexed(idx) => direct_page_indirect_long_indexed(bus, p.pc_addr, p.direct_page_register, if idx == X {p.x} else {p.y}),
Self::StackRelative => stack_relative(bus, p.pc_addr, p.stack_pointer, p.dbr),
Self::StackRelative => stack_relative(bus, p.pc_addr, p.stack_pointer),
Self::StackRelativeIndirectIndexed(idx) => stack_relative_indirect_indexed(bus, p.pc_addr, p.stack_pointer, if idx == X {p.x} else {p.y}, p.dbr),
}
}
@@ -490,15 +491,13 @@ mod addressing_modes_tests {
fn test_stack_relative() {
let mut bus = Bus::new();
let pc_addr = 0x000000;
bus.write(pc_addr + 1, 0x01);
bus.write(pc_addr + 2, 0x02);
assert_eq!(stack_relative(&mut bus, pc_addr, 0x02, 0x00), 0x000203);
bus.write(pc_addr + 1, 0x03);
assert_eq!(stack_relative(&mut bus, pc_addr, 0x200), 0x000203);
let mut bus = Bus::new();
let pc_addr = 0x7F0000;
bus.write(pc_addr + 1, 0x01);
bus.write(pc_addr + 2, 0x02);
assert_eq!(stack_relative(&mut bus, pc_addr, 0x02, 0x7F), 0x000203);
bus.write(pc_addr + 1, 0x03);
assert_eq!(stack_relative(&mut bus, pc_addr, 0x200), 0x000203);
}
#[test]