In computer science

Computer science

Computer science or computing science is the study of the theoretical foundations of information and computation and of practical techniques for their implementation and application in computer systems...

, a typed assembly language (TAL) is an assembly language

Assembly language

An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...

 that is extended to include a method of annotating the datatype of each value that is manipulated by the code. These annotations can then be used by a program (type checker) that processes the assembly language code in order to analyse how it will behave when it is executed. Specifically, such a type checker can be used to prove the type safety

Type safety

In computer science, type safety is the extent to which a programming language discourages or prevents type errors. A type error is erroneous or undesirable program behaviour caused by a discrepancy between differing data types...

 of code that meets the criteria of some appropriate type system

Type system

A type system associates a type with each computed value. By examining the flow of these values, a type system attempts to ensure or prove that no type errors can occur...

.

Typed assembly languages usually include a high-level memory management system based on garbage collection

Garbage collection (computer science)

In computer science, garbage collection is a form of automatic memory management. The garbage collector, or just collector, attempts to reclaim garbage, or memory occupied by objects that are no longer in use by the program...

.

A typed assembly language with a suitably expressive type system can be used to enable the safe execution of untrusted code without using an intermediate representation like bytecode

Bytecode

Bytecode, also known as p-code , is a term which has been used to denote various forms of instruction sets designed for efficient execution by a software interpreter as well as being suitable for further compilation into machine code...

, allowing features similar to those currently provided by virtual machine environments like Java and .NET

.NET Framework

The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...

.

Further reading

• Greg Morrisett
  Greg Morrisett
  John Gregory Morrisett is the Allen B. Cutting Professor of Computer Science and Associate Dean for Computer Science and Engineering in the Harvard School of Engineering and Applied Sciences....
  
  . "Typed assembly language" in Advanced Topics in Types and Programming Languages. Editor: Benjamin C. Pierce
  Benjamin C. Pierce
  Benjamin Crawford Pierce is an American professor of computer science at the University of Pennsylvania. Pierce joined Penn in 1998 from Indiana University and held research positions at the University of Cambridge and the University of Edinburgh. He received his Ph.D. from Carnegie Mellon...
  
  .

External links

• TALx86, a research project from Cornell University which has implemented a typed assembler for the Intel IA-32
  IA-32
  IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
  
  architecture.