Difference between revisions of "FPJ11 floating point accelerator"
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Although the DCJ11 contains a full implementation of the FP11 floating point [[instruction]]s, in [[microcode]], if a J-11 CPU board has an FPJ11 installed, the DCJ111 will automatically notice the presence of the FPJ11, and allow it to handle all floating-point instructions. | Although the DCJ11 contains a full implementation of the FP11 floating point [[instruction]]s, in [[microcode]], if a J-11 CPU board has an FPJ11 installed, the DCJ111 will automatically notice the presence of the FPJ11, and allow it to handle all floating-point instructions. | ||
| − | Addition of the FPJ11 improves floating-point | + | Addition of the FPJ11 improves floating-point performance by a factor of 5 to 8. The interface between the DCJ11 and the FPJ11 is designed to allow overlap between execution of floating point instructions in the FPJ11, and execution of non-floating point instructions in the DCJ11. |
==Versions== | ==Versions== | ||
Revision as of 21:30, 3 June 2023
The FPJ11 floating point accelerator is an optional floating point co-processor for the DCJ11 J-11 PDP-11 CPU chip, which implements the full FP11 floating point instruction set. The FPJ11 is a single chip which is plugged into a socket on a KDJ11 CPU card.
Although the DCJ11 contains a full implementation of the FP11 floating point instructions, in microcode, if a J-11 CPU board has an FPJ11 installed, the DCJ111 will automatically notice the presence of the FPJ11, and allow it to handle all floating-point instructions.
Addition of the FPJ11 improves floating-point performance by a factor of 5 to 8. The interface between the DCJ11 and the FPJ11 is designed to allow overlap between execution of floating point instructions in the FPJ11, and execution of non-floating point instructions in the DCJ11.
Versions
Two versions of the FPJ11 exist; the FPJ11-AA and the FPJ11-AB. DEC had a number of problems with 'corner cases' (e.g. DMA during certain floating point instructions), and had to issue revised versions of the FPJ11 and some J-11 CPU boards (e.g. the KDJ11-A) to fix them all.
External links
- DEC Semiconductor Databook, Volume 1, pp. 335-359
- FPJ11 Theory of Operation μNote #040, 17 September 1985
- DCJ11/FPJ11 Compatibility
Further reading
- μNote #025, "FPJ11-AA Compatibility with the LSI-11/73 (KDJ11-A)", 28 April 1985
| v • d • e PDP-11 Computers and Peripherals |
|---|
| UNIBUS PDP-11s - PDP-11/20 • PDP-11/15 • PDP-11/35 • PDP-11/40 • PDP-11/45 • PDP-11/50 • PDP-11/55 • PDP-11/70 PDP-11/05 • PDP-11/10 • PDP-11/04 • PDP-11/34 • PDP-11/60 • PDP-11/44 • PDP-11/24 • PDP-11/84 • PDP-11/94 QBUS PDP-11s - PDP-11/03 • PDP-11/23 • PDP-11/23+ • MicroPDP-11/73 • MicroPDP-11/53 • MicroPDP-11/83 • MicroPDP-11/93 QBUS CPUs: LSI-11 • LSI-11/2 • KDF11-A • KDF11-B • KDJ11-A • KDJ11-B • KDJ11-D • KDJ11-E Buses: UNIBUS • UNIBUS map • SPC • MUD • EUB • QBUS • CD interconnect • PMI Also: PDP-11 architecture • PDP-11 Extended Instruction Set • FP11 floating point • PDP-11 Memory Management |
| UNIBUS CPUs: KA11 • KC11 • KB11-A • KB11-B • KB11-C • KB11-D • KD11-A • KD11-B • KD11-D • KD11-E • KD11-EA • KD11-K • KD11-Z • KDF11-U
Co-processors: FP11-A • FP11-B • FP11-C • FP11-E • FP11-F • KE44-A • FPF11 Chips: LSI-11 • KEV11-A • KEV11-B • KEV11-C • F-11 • KEF11-A • KTF11-A • T-11 • J-11 • FPJ11 CPU options: KE11-E • KE11-F • KJ11-A • KT11-C • KT11-D • KK11-A • KK11-B • KT24 • KTJ11-B Rare CPU options: KS11 Memory Protection and Relocation option • KT11-B Paging Option • KUV11 Writeable Control Store Front panels: KY11-A • KY11-D • KY11-J • KY11-LA • KY11-LB • KY11-P More on buses: UNIBUS and QBUS termination • Bus Arbitration on the Unibus and QBUS • CTI BUS PDT-11s - PDT-11/110 • PDT-11/130 • PDT-11/150 CTI PDP-11s - PRO-325 • PRO-350 • PRO-380 Other: FIS floating point • PDP-11 Commercial Instruction Set • PDP-11 stacks • PDP-11 family differences |
