73 lines
2.3 KiB
Rust
73 lines
2.3 KiB
Rust
use crate::prelude::*;
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/// Not to be used directly, just call [`Instruction::encode`].
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pub trait Encode {
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fn encode(self, opcode: u8) -> u32;
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}
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/// Encodes a zero argument instruction.
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fn encode_no_args(opcode: u8) -> u32 {
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let opcode = u32::from(opcode);
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let sr1 = Register::NoReg as u32;
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let sr2 = Register::NoReg as u32;
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let dr = Register::NoReg as u32;
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let shamt = 0;
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(opcode << 26) | (sr1 << 21) | (sr2 << 16) | (dr << 11) | (shamt << 6)
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}
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/// Expands to a match statement that calls encode on instructions that implement
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/// [`Encode`]:
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///
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/// # Usage
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///
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/// ```rs
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/// encode_instruction!(self, with_args: [...], no_args: [...], special: [...] )
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/// ```
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macro_rules! encode_instruction {
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($self:expr, with_args: [$($variant:ident),+ $(,)?], no_args: [$($no_arg_variant:ident),* $(,)?] $(, special: [$($special:pat => $body:expr),* $(,)?])?) => {
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match $self {
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$(
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Instruction::$variant(args) => args.encode($self.opcode()),
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)+
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$(
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Instruction::$no_arg_variant => encode_no_args($self.opcode()),
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)*
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$($(
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$special => $body,
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)*)?
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}
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};
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}
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impl Encode for Instruction {
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fn encode(self, _: u8) -> u32 {
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encode_instruction!(
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self,
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with_args: [
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Mov, MovSigned, LoadByte, LoadByteSigned, LoadHalfword,
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LoadHalfwordSigned, LoadWord, StoreByte, StoreHalfword,
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StoreWord, LoadLowerImmediate, LoadUpperImmediate, Jump,
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JumpEq, JumpNeq, JumpGt, JumpGe, JumpLt, JumpLe, Compare,
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Add, Sub, Increment, Decrement, ShiftLeft, ShiftRight,
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And, Or, Not, Xor, Nand, Nor, Xnor, AddImmediate, SubImmediate
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],
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no_args: [Nop, IntReturn, Halt],
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special: [
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Self::Data(data) => data,
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Self::Interrupt(interrupt) => {
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let opcode = u32::from(self.opcode());
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(opcode << 26) | u32::from(interrupt.as_u8())
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},
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Self::Segment(segment) => {
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let opcode = u32::from(self.opcode());
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(opcode << 26) | u32::from(segment as u8)
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}
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]
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)
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}
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}
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#[cfg(test)]
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mod tests;
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