fuel-vm 0.2.0

FuelVM interpreter.
Documentation 
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use super::Interpreter;
use crate::consts::*;
use crate::error::RuntimeError;

use fuel_types::{RegisterId, Word};

impl<S> Interpreter<S> {
    pub(crate) fn alu_overflow<F, B, C>(&mut self, ra: RegisterId, f: F, b: B, c: C) -> Result<(), RuntimeError>
    where
        F: FnOnce(B, C) -> (Word, bool),
    {
        Self::is_register_writable(ra)?;

        let (result, overflow) = f(b, c);

        // TODO If the F_UNSAFEMATH flag is unset, an operation that would have set $err
        // to true is instead a panic.
        //
        // TODO If the F_WRAPPING flag is unset, an operation that would have set $of to
        // a non-zero value is instead a panic.

        self.registers[REG_OF] = overflow as Word;
        self.registers[REG_ERR] = 0;

        self.registers[ra] = result;

        self.inc_pc()
    }

    pub(crate) fn alu_error<F, B, C>(&mut self, ra: RegisterId, f: F, b: B, c: C, err: bool) -> Result<(), RuntimeError>
    where
        F: FnOnce(B, C) -> Word,
    {
        Self::is_register_writable(ra)?;

        self.registers[REG_OF] = 0;
        self.registers[REG_ERR] = err as Word;

        self.registers[ra] = if err { 0 } else { f(b, c) };

        self.inc_pc()
    }

    pub(crate) fn alu_set(&mut self, ra: RegisterId, b: Word) -> Result<(), RuntimeError> {
        Self::is_register_writable(ra)?;

        self.registers[REG_OF] = 0;
        self.registers[REG_ERR] = 0;

        self.registers[ra] = b;

        self.inc_pc()
    }

    pub(crate) fn alu_clear(&mut self) -> Result<(), RuntimeError> {
        self.registers[REG_OF] = 0;
        self.registers[REG_ERR] = 0;

        self.inc_pc()
    }
}