Editing PL/C (section)

== Cross compilers ==
In the early 1970s, three [[cross compiler]]s based on PL/C were created at the [[University of North Carolina]]; in these, the host platform was the IBM 360,<ref name="erda-plcv"/> and the target machine was one of several minicomputers in use at the time.  The PL/C language subset was used in these cross compilers,<ref name="siggraph-sat"/> as was the PL/C compiler's first two passes for syntax and semantic analysis.<ref name="erda-plci">{{cite book | url=https://books.google.com/books?id=DklNGDnHC5AC&pg=PA311 | title=ERDA Research Abstracts| volume=1 / #2 | publisher=United States Energy Research and Development Administration | location=Oak Ridge, Tennessee | date=February 1976 | page=311 }} Entry 2956; also entry 2957.</ref>  However the IBM 360 code generation pass and storage allocation modules were replaced by ones specific to the target architecture.<ref name="erda-plci"/>

The first of these cross compilers was PLCV (not to be confused with the PL/CV verifier), a cross compiler for [[Varian Data Machines]] minicomputers,<ref name="acm-sat"/> specifically the 620/i and 620/f, and was created around 1971.<ref name="erda-plcv">{{cite book | url=https://books.google.com/books?id=DklNGDnHC5AC&pg=PA474 | title=ERDA Research Abstracts| volume=1 / #3 | publisher=United States Energy Research and Development Administration | location=Oak Ridge, Tennessee | date=March 1976 | page=474 }} Entry 4422.</ref>  An improved version of PLCV came out around 1973.<ref name="erda-plci"/>  The second, PLCI, was targeted at the [[Interdata]] Model 3; it also had a revised version around the same time.<ref name="erda-plci"/>  The third was PLCD, used to target the [[Digital Equipment Corporation]]'s [[PDP-11/45]] minicomputer, which came out in 1973.<ref name="acm-sat"/>  Again, PLCD used PL/C but with the IBM 360 code generator replaced by one for PDP-11/45.<ref name="acm-sat"/><!-- the source mangles the description of this -->

The University of North Carolina used these cross compilers for real projects, not just education; in particular, PLCD was used in support of a [[graphical programming]] environment that would use the same programming language for both a general purpose mainframe and a graphical support minicomputer, thereby allowing easier shifting of code from one to the other.<ref name="siggraph-sat">{{cite conference | author-first=Griffith | author-last=Hamlin |author2-first=James D. | author2-last=Foley |year= 1975 | contribution=Configurable applications for graphics employing satellites (CAGES) | title= Proceedings of the 2nd annual conference on Computer graphics and interactive techniques (SIGGRAPH '75) | publisher= Association for Computing Machinery | pages= 9&ndash;19 | doi=10.1145/563732.563734 | doi-access=free }}</ref> The IBM PL/I F compiler was used on the mainframe, with programmers restricting themselves to the PL/C subset of the language, and PLCD was used to generate code for the PDP-11/45.<ref name="acm-sat">{{cite conference | author-first=James D. | author-last=Foley | year=1973 | contribution=Software for satellite graphics systems | title= Proceedings of the ACM annual conference (ACM '73) | publisher= Association for Computing Machinery  | pages= 76&ndash;80 | doi=10.1145/800192.805684 | doi-access=free }} </ref>