From: Luke Kenneth Casson Leighton Date: Sat, 29 Apr 2023 10:55:38 +0000 (+0100) Subject: clarify EXT022 Prefixed in PO9 encoding X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a4eb28edc34b840c5986de92fab4c16db71d3c38;p=libreriscv.git clarify EXT022 Prefixed in PO9 encoding --- diff --git a/openpower/sv/po9_encoding.mdwn b/openpower/sv/po9_encoding.mdwn index 7d041c06b..a330f70af 100644 --- a/openpower/sv/po9_encoding.mdwn +++ b/openpower/sv/po9_encoding.mdwn @@ -112,6 +112,17 @@ of this is that the Prefix Encoding is, like the 8086 REP instruction, an independent 32-bit Defined Word. The only semi-exceptions are the Post-Increment Mode of LD/ST-Update and Vectorised Branch-Conditional.* +Note a special application of the above paragraph: due to the fact that +the Prefix Encodings are independent, **by definition** two new Sandbox +areas "come into being" in an **inviolate** manner (i.e. they may not +be called anything else, nor may they be revoked rescinded removed or +recalled), named `SVP64:EXT022` and `SVP64Single:EXT022`. The **only +way** that these two new areas may be revoked is if EXT022 itself +is revoked. **All and any** re-definitions modifications enhancements +clarifications that apply to EXT022 **also apply to these two new areas** +because due to the Prefixes being independent Defined Words the three +areas are actually one and the same area. + Encoding spaces and their potential are illustrated: | Encoding |Available bits|Scalar|Vectoriseable | SVP64Single |PO1-Prefixable | diff --git a/openpower/sv/rfc/ls001.po9.mdwn b/openpower/sv/rfc/ls001.po9.mdwn index 37763fbf4..7f32bf0ee 100644 --- a/openpower/sv/rfc/ls001.po9.mdwn +++ b/openpower/sv/rfc/ls001.po9.mdwn @@ -62,7 +62,8 @@ New Primary Opcode areas are needed (beyond those already strictly defined as EXT1xx). New Primary Opcode areas EXT232-263 allows for immediate growth, allowing Power ISA to catch up 12-15 years on Intel and ARM. Also the Simple-V RISC-paradigm "Loop" subsystem based on x86 REP and Zilog Z80 -CPIR and LDIR may be cleanly and smoothly introduced. +CPIR and LDIR may be cleanly and smoothly introduced. Also several new +areas are RESERVED which allows significant future expansion. **Changes**