From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 10 Oct 2022 16:42:03 +0000 (+0100)
Subject: add bfloat16 definition
X-Git-Tag: opf_rfc_ls005_v1~99
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=c4a0e1371ad89372794852c5a830d335504387d4;p=libreriscv.git

add bfloat16 definition
---

diff --git a/openpower/sv/rfc/ls002.mdwn b/openpower/sv/rfc/ls002.mdwn
index dca0fb6a9..51a1ffa32 100644
--- a/openpower/sv/rfc/ls002.mdwn
+++ b/openpower/sv/rfc/ls002.mdwn
@@ -85,6 +85,7 @@ Add the following entries to:
 * the Appendices of Book I
 * Instructions of Book I as a new Section 4.6.2.1
 * DX-Form of Book I Section 1.6.1.6 and 1.6.2
+* Floating-Point Data a Format of Book I Section 4.3.1
 
 ----------------
 
@@ -199,6 +200,24 @@ Add `DX` to `FRT` Field in Book I, 1.6.2
      Formats: D, X, DX
 ```
 
+# bfloat16 definition
+
+Add the following to Book I, 4.3.1:
+
+The format may be a 16-bit bfloat16, 32-bit single format for a
+single-precision value...
+
+The bfloat16 format is used as an immediate.
+
+The structure of the bfloat16, single and double formats is shown below.
+
+```
+  |S |EXP| FRACTION|
+  |0 |1 8|9      15|
+```
+
+Figure #. Binary floating-point half-precision format (bfloat16)
+
 # Appendices
 
     Appendix E Power ISA sorted by opcode