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72 lines
3.9 KiB
Markdown
72 lines
3.9 KiB
Markdown
[](https://github.com/balt-dev/descape/actions/)
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[](https://docs.rs/r6502)
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[](https://gist.github.com/alexheretic/d1e98d8433b602e57f5d0a9637927e0c)
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[](https://github.com/balt-dev/r6502)
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[](https://crates.io/crates/r6502)
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[](https://github.com/balt-dev/r6502/blob/master/LICENSE-MIT)
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[](https://github.com/rust-secure-code/safety-dance/)
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# r6502
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### Yet another NMOS 6502 emulator.
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---
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Designed to support `no-std` and not require an allocator nor any unsafe code.
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The API of this crate shies away from implementing interrupt handling,
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instead having you step the emulator one opcode at a time and handle them yourself.
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## Feature Flags
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The following feature flags exist:
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| Name | Description |
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|-----------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| bcd | Enable binary-coded decimal arithmetic.<br/>Enabled by default. Disable if you're writing a NES emulator.<br/>Note that invalid BCD is left untested and will not function faithfully to the NMOS 6502. |
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| bytemuck | Enables [bytemuck](https://docs.rs/bytemuck/) support. |
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| arbitrary | Enables [arbitrary](https://docs.rs/arbitrary/) support. This will pull in `std`. |
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| serde | Enables [serde](https://docs.rs/serde) support. |
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| hashbrown | Enables [hashbrown](https://docs.rs/hashbrown) support. |
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## Example
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```rust ignore
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extern crate std;
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use std::eprintln;
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use r6502::{Emulator, FunctionReadCallback, FunctionWriteCallback};
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fn main() {
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let mut emu = Emulator::default()
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.with_read_callback(FunctionReadCallback(|state: &mut State, addr| {
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// Log reads
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eprintln!("Read from #${addr:04x}");
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state.memory[addr as usize]
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}))
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.with_write_callback(FunctionWriteCallback(|state: &mut State, addr, byte|
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// Don't write to ROM
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if addr < 0xFF00 {
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state.memory[addr as usize] = byte
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})
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)
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.with_rom(include_bytes!("rom.bin"))
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.with_program_counter(0x200);
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loop {
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let interrupt_requested = emu.step()
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.expect("found an invalid opcode (only NMOS 6502 opcodes are supported)");
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if interrupt_requested { // Go to IRQ interrupt vector
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let vector = u16::from_le_bytes([
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emu.read(0xFFFE),
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emu.read(0xFFFF)
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]);
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emu.state.program_counter = vector;
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}
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}
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}
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```
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---
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## Licensing
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This may be licensed under either the MIT or Apache-2.0 license, at your option.
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