Editing Cross compiler (section)

=== 1987 ===
C programs had long been linked with modules written in [[assembly language]]. Most C compilers (even current compilers) offer an assembly language pass (that can be tweaked for efficiency then linked to the rest of the program after assembling).

Compilers like Aztec-C converted everything to assembly language as a distinct pass and then assembled the code in a distinct pass, and were noted for their very efficient and small code, but by 1987 the optimizer built into Microsoft C was very good, and only "mission critical" parts of a program were usually considered for rewriting. In fact, C language programming had taken over as the "lowest-level" language, with programming becoming a multi-disciplinary growth industry and projects becoming larger, with programmers writing user interfaces and database interfaces in higher-level languages, and a need had emerged for cross language development that continues to this day.

By 1987, with the release of MSC 5.1, Microsoft offered a cross language development environment for MS-DOS. 16-bit binary object code written in assembly language ([[MASM]]) and Microsoft's other languages including [[QuickBASIC]], [[Pascal (programming language)|Pascal]], and [[Fortran]] could be linked together into one program, in a process they called "Mixed Language Programming" and now "InterLanguage Calling".<ref>[http://support.microsoft.com/kb/35965 Which Basic Versions Can CALL C, FORTRAN, Pascal, MASM]</ref> If [[BASIC]] was used in this mix, the main program needed to be in BASIC to support the internal [[runtime system]] that compiled BASIC required for garbage collection and its other managed operations that simulated a BASIC [[interpreter (computing)|interpreter]] like [[QBasic]] in MS-DOS.

The [[calling convention]] for C code, in particular, was to pass parameters in "reverse order" on the [[call stack|stack]] and return values on the stack rather than in a [[processor register]]. There were other programming rules to make all the languages work together, but this particular rule persisted through the cross language development that continued throughout [[Microsoft Windows|Windows]] 16- and 32-bit versions and in the development of programs for [[OS/2]], and which persists to this day. It is known as the [[Pascal calling convention]].

Another type of cross compilation that Microsoft C was used for during this time was in retail applications that require [[handheld device]]s like the [[Symbol Technologies]] PDT3100 (used to take [[inventory]]), which provided a link library targeted at an [[Intel 8088|8088]] based [[barcode reader]]. The application was built on the host computer then transferred to the handheld device (via a [[serial cable]]) where it was run, similar to what is done today for that same market using [[Windows Mobile]] by companies like [[Motorola]], who bought Symbol.