From: lkcl <lkcl@web>
Date: Fri, 28 Apr 2023 18:11:20 +0000 (+0100)
Subject: (no commit message)
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bd5c632a3e1e889f0778fb1406dbce7637743d37;p=libreriscv.git

---

diff --git a/openpower/sv/twin_butterfly.mdwn b/openpower/sv/twin_butterfly.mdwn
index deaf80d29..9933380e2 100644
--- a/openpower/sv/twin_butterfly.mdwn
+++ b/openpower/sv/twin_butterfly.mdwn
@@ -110,3 +110,27 @@ Special Registers Altered:
     VXSNAN VXISI VXIMZ
     CR1          (if Rc=1)
 ```
+
+# [DRAFT] Floating Multiply-Add FFT [Single]
+
+A-Form
+
+* ffmadds FRT,FRA,FRB (Rc=0)
+* ffmadds. FRT,FRA,FRB (Rc=1)
+
+Pseudo-code:
+
+```
+    tmp <- FRT
+    FRT <- FPMULADD32(tmp, FRA, FRB, 1, 1)
+    FRS <- FPMULADD32(tmp, FRA, FRB, -1, 1)
+```
+
+Special Registers Altered:
+
+```
+    FPRF FR FI
+    FX OX UX XX
+    VXSNAN VXISI VXIMZ
+    CR1          (if Rc=1)
+```