37 lines
913 B
Rust
37 lines
913 B
Rust
//
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// sprocketnes/mem.rs
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//
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// Author: Patrick Walton
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//
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//
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// The memory interface
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//
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/// The basic memory interface
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pub trait Mem {
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fn loadb(&mut self, addr: u16) -> u8;
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fn storeb(&mut self, addr: u16, val: u8);
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}
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pub trait MemUtil {
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fn loadw(&mut self, addr: u16) -> u16;
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fn storew(&mut self, addr: u16, val: u16);
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fn loadw_zp(&mut self, addr: u8) -> u16;
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}
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impl<M:Mem> MemUtil for M {
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fn loadw(&mut self, addr: u16) -> u16 {
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self.loadb(addr) as u16 | (self.loadb(addr + 1) as u16 << 8)
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}
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fn storew(&mut self, addr: u16, val: u16) {
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self.storeb(addr, (val & 0xff) as u8);
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self.storeb(addr + 1, ((val >> 8) & 0xff) as u8);
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}
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// Like loadw, but has wraparound behavior on the zero page for address 0xff.
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fn loadw_zp(&mut self, addr: u8) -> u16 {
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self.loadb(addr as u16) as u16 | (self.loadb((addr + 1) as u16) as u16 << 8)
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}
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}
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