PerqFlex Firmware,
Abstract
This report describes the firmware architecture of the Flex computing system as implemented on the ICL Perq. This implementation is very similar to that described in RSRE Report 81009, (Flex Firmware by Currie, Edwards and Foster) generally referred to as the Logica implementation. This is rather a misnomer, since although Logica built the hardware (to an RSRE design) on which it was implemented, Logica had nothing to do with the micro-coding or software construction of the Flex architecture. The differences between the Perq and Logica implementation arise mainly from the properties of the underlying hardware. In the Logica Flex, for example, each byte in main-store was in fact nine bits long rather than eight; the extra bits (the tag bits) were used to distinguish between pointers and non-pointers ie between capabilities and scalar data. On Perq, however, there are no bits to spare like this. In order to distinguish between pointers and non-pointers in Perq, it was necessary to steel a bit from each 32-bit word to act as a tag bit. (Great Britain).
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1985
- Accession Number
- ADA166398
Entities
People
- I. F. Currie
- J. M. Foster
- P. W. Edwards
Organizations
- Royal Signals and Radar Establishment