68 lines
2.0 KiB
Rust
68 lines
2.0 KiB
Rust
use crate::constants::constants_system::SIZE_32KB;
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use crate::periph::at28c256::At28C256;
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use crate::periph::hm62256::Hm62256;
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impl At28C256 {
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fn talking_to_me(&self, address: u16) -> bool {
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address >= self.offset && address < self.max_offset
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}
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pub fn tick(&mut self, address_bus: u16, data_bus: u8, read_mode: bool) -> (u16, u8) {
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println!("At28C256: Tick starting for A${address_bus:04x} D${data_bus:02x} R{read_mode}");
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// we aren't being addressed
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// OR
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// we arent reading from the ROM...
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if !self.talking_to_me(address_bus) ||
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!read_mode {
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// ...go away.
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return (address_bus, data_bus)
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}
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let effective = address_bus - self.offset;
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if effective < self.max_offset {
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if effective < self.data.len() as u16 {
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self.data_bus = self.data[effective as usize];
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} else {
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self.data_bus = 0x00;
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}
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} else {
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println!("At28C256: OUTSIDE RANGE. :(");
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return (address_bus, data_bus)
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}
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println!("At28C256: Read... {:02x}", self.data_bus);
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println!("At28C256: Done with ticking the AtC256");
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(address_bus, self.data_bus)
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}
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}
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#[cfg(test)]
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mod test {
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use std::fs;
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use crate::periph::rom_chip::RomChip;
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use super::*;
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#[test]
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fn smoke() { assert!(true); }
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#[test]
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fn checksum_binary_loads() {
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let path = "/home/tmerritt/Projects/mos6502/resources/test/periph/at28c256/checksum.bin";
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let bytes = match fs::read(path) {
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Ok(bytes) => {
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println!("Read {} bytes.", bytes.len());
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bytes
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},
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Err(e) => {
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eprintln!("FAIL to read rom.");
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panic!("No rom no run.");
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vec![]
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}
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};
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let mut rom = At28C256::new(0x0000, 0x3fff, bytes);
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assert_eq!(rom.checksum(), 0x58);
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}
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} |