PL/M

The PL/M programming language (an acronym of Programming Language for Microcomputers) is a high-level language developed by Gary Kildall in 1972 for Intel for its microprocessors.

The language incorporated ideas from PL/I, ALGOL and XPL, and had an integrated macro processor. Unlike other contemporary languages such as Pascal, C or BASIC, PL/M had no standard input or output routines. It included features targeted at the low-level hardware specific to the target microprocessors, and as such, it could support direct access to any location in memory, I/O ports and the processor interrupt flags in a very efficient manner. PL/M was the first higher level programming language for microprocessor based computers and the original implementation language for the CP/M operating system. Also the firmware of the Service Processor component of CISC AS/400 was written in PL/M. PL/M compilers have been made for the following processors/controllers: 8008, 8080, 8085, 8051, 8052, 8096, 80196, 8086/8088, 80186/80188, 286, and 386. While some PL/M compilers were "native", meaning that they ran on systems using that same microprocessor, e.g. for the Intel ISIS operating system, there were also "cross compilers" which ran on other operating environments such as Microsoft's DOS, and Digital Equipment Corporation's VAX/VMS.