Instructions¶

enum UNIT_Instruction¶

Enumerated type containing the ID for all UNIT stack-based instructions.

enumerator UNIT_OP_LOAD_STRING¶

enumerator UNIT_OP_LOAD_INTEGER¶

enumerator UNIT_OP_ADD¶

enumerator UNIT_OP_SUBTRACT¶

enumerator UNIT_OP_MULTIPLY¶

enumerator UNIT_OP_DIVIDE¶

enumerator UNIT_OP_MODULO¶

enumerator UNIT_OP_RETURN_VALUE¶

enumerator UNIT_OP_EXIT¶

enumerator UNIT_OP_POP¶

enumerator UNIT_OP_PREPARE_CALL¶

enumerator UNIT_OP_CALL_NAME¶

enumerator UNIT_OP_STORE_LOCAL¶

enumerator UNIT_OP_LOAD_LOCAL¶

enumerator UNIT_OP_ADDRESS_OF¶

enumerator UNIT_OP_COMPARE_EQUAL¶

enumerator UNIT_OP_COMPARE_NOT_EQUAL¶

enumerator UNIT_OP_COMPARE_GREATER¶

enumerator UNIT_OP_COMPARE_GREATER_EQUAL¶

enumerator UNIT_OP_COMPARE_LESS¶

enumerator UNIT_OP_COMPARE_LESS_EQUAL¶

enumerator UNIT_OP_JUMP_TO¶

enumerator UNIT_OP_JUMP_IF_TRUE¶

enumerator UNIT_OP_JUMP_IF_FALSE¶

enumerator UNIT_OP_COPY¶

enumerator UNIT_OP_SWAP¶

enumerator UNIT_OP_READ_BYTES¶

enumerator UNIT_OP_WRITE_BYTES¶

enumerator UNIT_OP_CAST¶

enumerator UNIT_OP_PUSH_VIRTUAL¶

Constants¶

Opcode	Effect	Description
`UNIT_OP_LOAD_INTEGER`	`stack.push(oparg)`	Push a constant 32-bit integer onto the stack.
`UNIT_OP_LOAD_STRING`	`stack.push(strings[oparg])`	Push a constant string onto the stack.

Arithmetic¶

Opcode	Effect	Description
`UNIT_OP_ADD`	`stack.push(stack.pop(top - 1) + stack.pop(top))`	Add two numbers together.
`UNIT_OP_SUBTRACT`	`stack.push(stack.pop(top - 1) - stack.pop(top))`	Subtract two numbers.
`UNIT_OP_MULTIPLY`	`stack.push(stack.pop(top - 1) * stack.pop(top))`	Multiply two numbers together.
`UNIT_OP_DIVIDE`	`stack.push(stack.pop(top - 1) / stack.pop(top))`	Divide two numbers.
`UNIT_OP_MODULO`	`stack.push(stack.pop(top - 1) % stack.pop(top))`	Take the remainder of two numbers.

Local Variables¶

Opcode	Effect	Description
`UNIT_OP_STORE_LOCAL`	`locals[oparg] = stack.pop(top)`	Store a value into a local variable.
`UNIT_OP_LOAD_LOCAL`	`stack.push(locals[oparg])`	Read the value of a local variable.
`UNIT_OP_ADDRESS_OF`	`stack.push(&locals[oparg])`	Push the memory address of a local variable.

Memory Access¶

Opcode	Effect	Description
`UNIT_OP_READ_BYTES`	`stack.push(read(stack.pop(top), oparg))`	Read `oparg` bytes from a memory address.
`UNIT_OP_WRITE_BYTES`	`write(stack.pop(top - 1), stack.pop(top), oparg)`	Write `oparg` bytes to a memory address.

Comparisons¶

Opcode	Effect	Description
`UNIT_OP_COMPARE_EQUAL`	`stack.push(stack.pop(top - 1) == stack.pop(top))`	Compare two values for equality.
`UNIT_OP_COMPARE_NOT_EQUAL`	`stack.push(stack.pop(top - 1) != stack.pop(top))`	Compare two values for inequality.
`UNIT_OP_COMPARE_GREATER`	`stack.push(stack.pop(top - 1) > stack.pop(top))`	Check whether a value is greater than another.
`UNIT_OP_COMPARE_GREATER_EQUAL`	`stack.push(stack.pop(top - 1) >= stack.pop(top))`	Check whether a value is greater than or equal to another.
`UNIT_OP_COMPARE_LESS`	`stack.push(stack.pop(top - 1) < stack.pop(top))`	Check whether a value is less than another.
`UNIT_OP_COMPARE_LESS_EQUAL`	`stack.push(stack.pop(top - 1) <= stack.pop(top))`	Check whether a value is less than or equal to another.

Control Flow¶

Opcode	Effect	Description
`UNIT_OP_JUMP_TO`	`goto jump_labels[oparg]`	Unconditionally jump to a label.
`UNIT_OP_JUMP_IF_TRUE`	`if stack.pop(top): goto jump_labels[oparg]`	Jump to a label if the top of the stack is nonzero.
`UNIT_OP_JUMP_IF_FALSE`	`if not stack.pop(top): goto jump_labels[oparg]`	Jump to a label if the top of the stack is zero.

Function Calls¶

Opcode	Effect	Description
`UNIT_OP_PREPARE_CALL`	Collects `oparg` items from the stack as call arguments.	Prepare arguments for a function call. Used internally by `UNIT_Procedure_AddCall()`.
`UNIT_OP_CALL_NAME`	`stack.push(names[oparg](args))`	Call a named function and push its return value.
`UNIT_OP_PUSH_VIRTUAL`	`stack.push(<parameter>)`	Declare a procedure parameter. Used at the start of a procedure body.

Stack Manipulation¶

Opcode	Effect	Description
`UNIT_OP_POP`	`stack.pop(top)`	Discard the value on top of the stack.
`UNIT_OP_COPY`	`stack.push(stack[top - oparg])`	Duplicate a stack item. With no argument, copies the top.
`UNIT_OP_SWAP`	`swap(stack[top], stack[top - oparg])`	Swap two stack items. With no argument, swaps the top two.

Type Conversion¶

Opcode	Effect	Description
`UNIT_OP_CAST`	`stack.push((type)stack.pop(top))`	Cast the top of the stack to the integer type specified by `oparg`.

Program Control¶

Opcode	Effect	Description
`UNIT_OP_RETURN_VALUE`	`return stack.pop(top)`	Return a value and end execution of the current procedure.
`UNIT_OP_EXIT`	`exit(stack.pop(top))`	Exit the entire program with the given status code.