Content deleted Content added
CyberOne25 (talk | contribs) mNo edit summary Tags: Visual edit Mobile edit Mobile web edit Advanced mobile edit |
MichaelMaggs (talk | contribs) Adding short description: "Computer designed to run a specific language" |
||
| (2 intermediate revisions by 2 users not shown) | |||
Line 1:
{{Short description|Computer designed to run a specific language}}
A '''high-level language computer architecture''' ('''HLLCA''') is a [[computer architecture]] designed to be targeted by a specific [[high-level programming language]] (HLL), rather than the architecture being dictated by hardware considerations. It is accordingly also termed '''language-directed computer design''', coined in {{harvtxt|McKeeman|1967}} and primarily used in the 1960s and 1970s. HLLCAs were popular in the 1960s and 1970s, but largely disappeared in the 1980s. This followed the dramatic failure of the [[Intel 432]] (1981) and the emergence of [[optimizing compiler]]s and [[reduced instruction set computer]] (RISC) architectures and RISC-like [[complex instruction set computer]] (CISC) architectures, and the later development of [[just-in-time compilation]] (JIT) for HLLs. A detailed survey and critique can be found in {{harvtxt|Ditzel|Patterson|1980}}.
Line 4 ⟶ 5:
==Definition==
There are a wide variety of systems under this heading. The most extreme example is a Directly Executed Language (DEL), where the [[instruction set architecture]] (ISA) of the computer equals the instructions of the HLL, and the [[source code]] is directly executable with minimal processing. In extreme cases, the only compiling needed is [[Tokenization (lexical analysis)|tokenizing]] the source code and feeding the tokens directly to the processor; this is found in [[stack-oriented programming language]]s running on a [[stack machine]]. For more conventional languages, the HLL statements are grouped into instruction + [[Parameter (computer programming)|arguments]], and [[Infix notation|infix]] order is transformed to [[Substring|prefix]] or [[Reverse Polish notation|postfix]] order. DELs are typically only hypothetical, though they were advocated in the 1970s.<ref>See Yaohan Chu references.</ref>
In less extreme examples, the source code is first parsed to [[bytecode]], which is then the [[machine code]] that is passed to the processor. In these cases, the system typically lacks an [[Assembly language|assembler]], as the [[compiler]] is deemed sufficient, though in some cases (such as Java), assemblers are used to produce legal bytecode which would not be output by the compiler. This approach was found in the [[Pascal MicroEngine]] (1979), and is currently used by Java processors.
Line 24 ⟶ 25:
[[Rekursiv]] (mid-1980s) was a minor system, designed to support [[object-oriented programming]] and the [[Lingo (programming language)#Other languages|Lingo]] programming language in hardware, and supported [[recursion]] at the instruction set level, hence the name.
A number of processors and coprocessors intended to implement [[Prolog]] more directly were designed in the late 1980s and early 1990s, including the [http://www.eecs.berkeley.edu/Pubs/TechRpts/1991/6379.html Berkeley VLSI-PLM], its successor (the [http://portal.acm.org/citation.cfm?id=74948 PLUM]), and a [http://www.eecs.berkeley.edu/Pubs/TechRpts/1988/5870.html related microcode implementation]. There were also a number of simulated designs that were not produced as hardware [
[[Niklaus Wirth]]'s [[Lilith (computer)|Lilith]] project included a custom CPU geared toward the [[Modula-2]] language.<ref>{{cite web |url=http://pascal.hansotten.com/index.php?page=history-of-lilith |title=Pascal for Small Machines – History of Lilith |publisher=Pascal.hansotten.com |date=28 September 2010 |access-date=12 November 2011 |archive-date=20 March 2012 |archive-url=https://web.archive.org/web/20120320091110/http://pascal.hansotten.com/index.php?page=history-of-lilith |url-status=dead }}</ref>
| |||