PL.8

PL.8 is a dialect of PL/I developed by IBM Research in the 1970s by compiler group, under Martin Hopkins, within a major research program that led to the IBM RISC architecture.^[1] It was so-called because it was about 80% of PL/I.^[1] Written in PL/I and bootstrapped via the PL/I Optimizing compiler, it was an alternative to PL/S for system programming, compiling initially to an intermediate machine-independent language with symbolic registers and machine-like operations.^[2] It applied machine-independent program optimization techniques to this intermediate language to produce exceptionally good object code. The intermediate language was mapped by the back-end to the target machine's register architecture and instruction set. Back-ends were written for IBM 801, S/370, Motorola 68000,^[3][4] and POWER/PowerPC.^{[citation needed]} A version was used on IBM mainframes as a development tool for software that was being designed for the IBM AS/400, as well as to write the "i370" internal code for the "Capitol" chipset used in the IBM 9377 processor and some ES/9370 models^[5][6] and the millicode for S/390 and z/Architecture processors.^[7]

References

1. Cocke, John; Markstein, V. (January 1990). "The evolution of RISC technology at IBM" (PDF). IBM Journal of Research & Development. 34 (1). IBM: 4–11. doi:10.1147/rd.341.0004. Retrieved 2008-03-06.
2. The compiler is described in: George Radin (May 1983). "The 801 Minicomputer". IBM Journal of Research and Development. 27 (3): 237–246. doi:10.1147/rd.273.0237.
3. Marc Auslander; Martin Hopkins (June 1982). "An Overview of the PL.8 Compiler" (PDF). SIGPLAN Notices. 17 (6).
4. Charles H. Ferguson; Charles R. Morris (1993). Computer Wars: The Post-IBM World. Beard Books. p. 44. ISBN 978-1-58798-139-5.
5. Maergner, Juergen; Schwermer, Hartmut R. (September 1988). "I370 - a new dimension of microprogramming". ACM SIGMICRO Newsletter. 19 (3): 24–31. doi:10.1145/62185.62189. ISSN 1050-916X. S2CID 2068407.
6. Wilhelm Spruth, ed. (6 December 2012). "7.2 High Level Microprogramming in I370". The Design of a Microprocessor. Springer-Verlag. ISBN 978-3-642-74918-6.
7. Gellerich, W.; Hendel, T.; Land, R.; Lehmann, H.; Mueller, M.; Oden, P.H.; Penner, H. (May 2004). "The GNU 64-bit PL8 compiler: Toward an open standard environment for firmware development". IBM Journal of Research and Development. 48 (3.4): 543–556. doi:10.1147/rd.483.0543.