From a54986d296c381e45f9990e7f1c76da4a07970cb Mon Sep 17 00:00:00 2001 From: lkcl Date: Mon, 3 Apr 2023 13:34:31 +0100 Subject: [PATCH] --- openpower/sv/rfc/ls010.mdwn | 85 ++++++++++++++++++++++++++++++++++++- 1 file changed, 84 insertions(+), 1 deletion(-) diff --git a/openpower/sv/rfc/ls010.mdwn b/openpower/sv/rfc/ls010.mdwn index ec9c8ba20..21d81e71b 100644 --- a/openpower/sv/rfc/ls010.mdwn +++ b/openpower/sv/rfc/ls010.mdwn @@ -1,6 +1,89 @@ # RFC ls010 SVP64 Zero-Overhead Loop Prefix Subsystem +**URLs**: -TODO template from other RFCs +* +* +* +* + +**Severity**: Major + +**Status**: New + +**Date**: 04 Apr 2023 v1 + +**Target**: v3.2B + +**Source**: v3.0B + +**Books and Section affected**: + +``` + New Book: new Zero-Overhead-Loop + New Appendix, Zero-Overhead-Loop +``` + +**Summary** + +``` + Adds a Zero-Overhead-Loop Subsystem based on the Cray True-Scalable Vector concept + in a RISC-paradigm fashion. Total instructions added is six, plus Prefix format. +``` + +**Submitter**: Luke Leighton (Libre-SOC) + +**Requester**: Libre-SOC + +**Impact on processor**: + +``` + Addition of new "Zero-Overhead-Loop-Control" DSP-style Vector-style + subsystem that in simple low-end (Embedded) systems may be minimalistically + and easily be implemented by inserting a new fully-independent Pipeline Stage + in between Decode and Issue, with very little disruption, and in higher + performance pre-existing Multi-Issue Out-of-Order systems seamlessly fits likewise + to significantly boost performance. +``` + +**Impact on software**: + +``` + Requires support for new instructions in assembler, debuggers, and related tools. + Dramatically reduces instructions. Requires introduction of term "High-Level Assembler" +``` + +**Keywords**: + +``` + Cray Supercomputing, Vectorisation, Zero-Overhead-Loop-Control (ZOLC), + True-Scalable Vectors, Multi-Issue Out-of-Order, Sequential Programming Model, + Digital Signal Processing (DSP), High-level Assembler +``` + +**Motivation** + +SIMD is getting out of control and damaging the reputation of mainstream +general-purpose ISAs that offer it. A solution from 50 years ago exists +in the form of Cray-Style True-Scalable Vectors. However the usual way that +True-Scalable Vector ISAs are done *also* adds more instructions and +complexifies the ISA. Simple-V takes a step back to a simpler era in +computing from half a century ago: the Zilog Z80 CPIR and LDIR instructions, +and the 8086 REP instruction, and brings them forward to Modern-day Computing. +The result is a huge reduction in programming complexity, and a strong +base to project the Power ISA back to the most powerful Supercomputing ISA +for at least the next two decades. + +**Notes and Observations**: + +1. TODO + +**Changes** + +Add the following entries to: + +* A new "Vector Looping" Book +* New Vector-Looping Chapters +* New Vector-Looping Appendices [[!tag opf_rfc]] -- 2.30.2