From: lkcl Date: Wed, 29 Mar 2023 17:29:29 +0000 (+0100) Subject: (no commit message) X-Git-Tag: opf_rfc_ls012_v1~237 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bc92ee3faf52bd9bd612a36dc987b5766918a5a8;p=libreriscv.git --- diff --git a/openpower/sv/rfc/ls010.mdwn b/openpower/sv/rfc/ls010.mdwn index 0d54ff69f..6d6ab6e37 100644 --- a/openpower/sv/rfc/ls010.mdwn +++ b/openpower/sv/rfc/ls010.mdwn @@ -108,9 +108,10 @@ because there is only one `MSR`. ## Register files, elements, and Element-width Overrides -In the Upper Compliancy Levels the size of the GPR and FPR Register +In the Upper Compliancy Levels of SVP64 the size of the GPR and FPR Register files are expanded from 32 to 128 entries, and the number of CR Fields -expanded from CR0-CR7 to CR0-CR127. +expanded from CR0-CR7 to CR0-CR127. (Note: A future version of SVP64 is anticipated +to extend the VSR register file). Memory access remains exactly the same: the effects of `MSR.LE` remain exactly the same, affecting as they already do and remain **only** @@ -118,11 +119,19 @@ on the Load and Store memory-register operation byte-order, and having nothing to do with the ordering of the contents of register files or register-register operations. +To be absolutely clear: + +**No conceptual arithmetic ordering or other changes over the Scalar Power ISA +definitions to registers or register files +or to arithmetic or Logical Operations beyond element-width subdivision and +sequential element numbering are expressed or implied** + Whilst the bits within the GPRs and FPRs are expected to be MSB0-ordered and for numbering to be sequentially incremental the element offset numbering is naturally **LSB0-sequentially-incrementing from zero not MSB0-incrementing.** Expressed exclusively in MSB0-numbering, SVP64 is -unnecessarily complex to understand: the required subtractions from 63, +becomes unnecessarily complex to both express and subsequently understand: +the required subtractions from 63, 31, 15 and 7 unfortunately become a hostile minefield. Therefore for the purposes of this section the more natural **LSB0 numbering is assumed** and it is up to the reader to translate to MSB0 numbering.