Enum acs::vm::instruction::VmInstruction

pub enum VmInstruction {
    Push(Segment, u16),
    Pop(Segment, u16),
    Add,
    Sub,
    Eq,
    Lt,
    Gt,
    Neg,
    And,
    Or,
    Not,
    Label(String),
    Goto(String),
    IfGoto(String),
    Function(String, u16),
    Call(String, u16),
    Return(u16),
}

Sort of intermediate code designed to run on a stack machine. Part of a two-tier compilation model, where a high level language is first translated to this representation and then to machine language.

Variants

Push(Segment, u16)

Pushes segment[index] on top of the stack

Pop(Segment, u16)

Pops an element from the stack and stores it into segment[index]

Add

Pops y, pops x, and pushes x + y

Sub

Pops y, pops x, and pushes x - y

Eq

Pops y, pops x, and pushes x == y

Lt

Pops y, pops x, and pushes x < y

Gt

Pops y, pops x, and pushes x > y

Neg

Pops x, and pushes -x

And

Pops y, pops x, and pushes x & y

Or

Pops y, pops x, and pushes x | y

Not

Pops x, and pushes ~x (bitwise not)

Label(String)

Marks current code location for jumping

Goto(String)

Unconditional jump to the location marked by the label

IfGoto(String)

Pops topmost value from stack and, if it is not 0, jumps to the location marked by the label

Function(String, u16)

Marks the beginning of a function with a name and the number of words to allocate for the local segment

Call(String, u16)

Calls the function with that name with the number of arguments pushed onto the stack before calling.

Return(u16)

Jumps to the command following the Call command that called the current function, copying a number of words as the return value at the beginning of the Argument section.

Implementations

impl VmInstruction

pub fn parse(code: &str) -> Vec<VmInstruction>

Trait Implementations

impl Clone for VmInstruction

fn clone(&self) -> VmInstruction

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for VmInstruction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromStr for VmInstruction

type Err = String

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl PartialEq<VmInstruction> for VmInstruction

fn eq(&self, other: &VmInstruction) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for VmInstruction

impl StructuralEq for VmInstruction

impl StructuralPartialEq for VmInstruction