From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 10 Oct 2022 16:20:14 +0000 (+0100)
Subject: convert fp32 to bfp32, fix FRS->FRT
X-Git-Tag: opf_rfc_ls005_v1~103
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=187453979089c90b5b3118e6c1a970de3c0a28ba;p=libreriscv.git

convert fp32 to bfp32, fix FRS->FRT
---

diff --git a/openpower/sv/rfc/ls002.mdwn b/openpower/sv/rfc/ls002.mdwn
index a762e31f7..d02a542f7 100644
--- a/openpower/sv/rfc/ls002.mdwn
+++ b/openpower/sv/rfc/ls002.mdwn
@@ -73,8 +73,8 @@ and TLB lookup. Even quickly clearing an FPR to zero presently requires Load.
   is an immediate loading instruction.  No FPR Load Operations
   alter `FPSCR`, neither does `lxvkq`, and on that basis neither
   should these instructions.
-3. `fishmv` as a FRS-only Read-Modify-Write (instead of an unnecessary
-  FRS,FRA pair) saves five potential bits, making
+3. `fishmv` as a FRT-only Read-Modify-Write (instead of an unnecessary
+  FRT,FRA pair) saves five potential bits, making
   the difference between a 5-bit XO (VA/DX-Form) and requiring an entire
   Primary Opcode.
 
@@ -101,9 +101,9 @@ Add the following entries to:
 Pseudocode:
 
 ```
-    bf16 <- d0 || d1 || d2 # create bfloat16 immediate
-    fp32 <- bf16 || [0]*16 # convert bfloat16 to BFP32
-    FRT <- DOUBLE(fp32)    # convert BFP32 to BFP64
+    bf16 <- d0 || d1 || d2  # create bfloat16 immediate
+    bfp32 <- bf16 || [0]*16 # convert bfloat16 to BFP32
+    FRT <- DOUBLE(bfp32)    # convert BFP32 to BFP64
 ```
 
 Special registers altered:
@@ -140,10 +140,10 @@ DX-Form:
 Pseudocode:
 
 ```
-    n <- (FRT)                     # read FRT
-    fp32 <- SINGLE(n)              # convert to BFP32
-    fp32[16:31] <- d0 || d1 || d2  # replace LSB half
-    FRT <- DOUBLE(fp32)            # convert back to BFP64
+    n <- (FRT)                      # read FRT
+    bfp32 <- SINGLE(n)              # convert to BFP32
+    bfp32[16:31] <- d0 || d1 || d2  # replace LSB half
+    FRT <- DOUBLE(bfp32)            # convert back to BFP64
 ```
 
 Special registers altered:
@@ -190,10 +190,10 @@ Add the following to Book I, 1.6.1.6, DX-Form
   | PO  | FRT|   d1|   d0|   XO|d2
 ```
 
-Add `DX` to `FRS` Field in Book I, 1.6.2
+Add `DX` to `FRT` Field in Book I, 1.6.2
 
 ```
- FRS (6:10)
+ FRT (6:10)
      Field used to specify an FPR to be used as a
      source.
      Formats: D, X, DX