From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 25 Mar 2023 14:31:28 +0000 (+0000)
Subject: update nunmber of instructions (to 8, sigh), clarify heading
X-Git-Tag: opf_rfc_ls001_v3~75
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0acbcae658f7571723b71bf7b742391e0302192e;p=libreriscv.git

update nunmber of instructions (to 8, sigh), clarify heading
for each instruction explicitly saying "Double-Precision"
https://bugs.libre-soc.org/show_bug.cgi?id=1015
---

diff --git a/openpower/sv/rfc/ls006.mdwn b/openpower/sv/rfc/ls006.mdwn
index 1059568f7..34606f77d 100644
--- a/openpower/sv/rfc/ls006.mdwn
+++ b/openpower/sv/rfc/ls006.mdwn
@@ -28,12 +28,19 @@
 
 **Summary**
 
-Instructions added
+Single-precision Instructions added:
 
-* `fmvtg` -- Floating Move To GPR
-* `fmvfg` -- Floating Move From GPR
-* `fcvttg` -- Floating Convert To Integer In GPR
-* `fcvtfg` -- Floating Convert From Integer In GPR
+* `fmvtgs` -- Single-Precision Floating Move To GPR
+* `fmvfgs` -- Single-Precision Floating Move From GPR
+* `fcvttgs` -- Single-Precision Floating Convert To Integer In GPR
+* `fcvtfgs` -- Single-Precision Floating Convert From Integer In GPR
+
+Identical (except Double-precision) Instructions added:
+
+* `fmvtg` -- Double-Precision Floating Move To GPR
+* `fmvfg` -- Double-Precision Floating Move From GPR
+* `fcvttg` -- Double-Precision Floating Convert To Integer In GPR
+* `fcvtfg` -- Double-Precision Floating Convert From Integer In GPR
 
 **Submitter**: Luke Leighton (Libre-SOC)
 
@@ -41,7 +48,8 @@ Instructions added
 
 **Impact on processor**:
 
-* Addition of five new GPR-FPR-based instructions
+* Addition of four new Single-Precision GPR-FPR-based instructions
+* Addition of four new Double-Precision GPR-FPR-based instructions
 
 **Impact on software**:
 
@@ -73,6 +81,10 @@ implements each variant.
 * These instructions are present in many other ISAs.
 * JavaScript rounding as one instruction saves 35 instructions including
   six branches. (FIXME: disagrees with int_fp_mv and int_fp_mv/appendix)
+* Both sets are orthogonal (no difference except being Single/Double).
+  This allows IBM to follow the pre-existing precedent of allocating
+  separate Major Opcodes (PO) for Double-precision and Single-precision
+  respectively.
 
 **Changes**
 
@@ -180,7 +192,7 @@ Special Registers altered:
 
 \newpage{}
 
-## Floating Move From GPR
+## Double-Precision Floating Move From GPR
 
 ```
     fmvfg FRT, RB
@@ -240,7 +252,7 @@ Special Registers altered:
 
 \newpage{}
 
-## Floating Convert From Integer In GPR
+## Double-Precision Floating Convert From Integer In GPR
 
 ```
     fcvtfg FRT, RB, IT
@@ -520,7 +532,7 @@ Section 7.1 of the ECMAScript / JavaScript
 \newpage{}
 
 
-## Floating Convert To Integer In GPR
+## Double-Precision Floating Convert To Integer In GPR
 
 ```
     fcvttg RT, FRB, CVM, IT