From: lkcl <lkcl@web>
Date: Fri, 25 Oct 2019 15:45:09 +0000 (+0100)
Subject: (no commit message)
X-Git-Tag: convert-csv-opcode-to-binary~3841
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=abae9c64fab666221f79fa63b7103531a34b047f;p=libreriscv.git

---

diff --git a/openpower.mdwn b/openpower.mdwn
index 064bdc74a..ac5aaaf73 100644
--- a/openpower.mdwn
+++ b/openpower.mdwn
@@ -44,3 +44,8 @@ Store activation length in a CSR.
 
 2nd idea: 11 bits can be used for extremely common operations, then length-encoding page selection for further ops, using the full 16 bit range and an entirely new encoding scheme. 1 bit specifies which of 2 pages was selected?
 
+3rd idea: "stack" mechanism. Allow subpages like a stack, to page in new pages.
+
+3 bits for subpage number. 4 bits for length, gives 7 bits. 4x7 is 28, then 3 bits can be used to specify "stack depth".
+
+Requirements are to have one instruction in each subpage which resets all the way back to PowerISA default. The other is a "back up stack by 1".