From d4794bd731d407a9c7a39ce7938c507dd6d2514a Mon Sep 17 00:00:00 2001
From: lkcl <lkcl@web>
Date: Tue, 15 Mar 2022 21:28:08 +0000
Subject: [PATCH]

---
 openpower/sv/bitmanip.mdwn | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/openpower/sv/bitmanip.mdwn b/openpower/sv/bitmanip.mdwn
index 3774322ed..f319d5147 100644
--- a/openpower/sv/bitmanip.mdwn
+++ b/openpower/sv/bitmanip.mdwn
@@ -270,6 +270,20 @@ Immediate-variant is an overwrite form:
 | NN | RS | RB  | sh  | SH | itype | 1000 110 |Rc| bm*i |
 
 ```
+def MASK(x, y):
+     if x < y:
+         x = x+1
+         mask_a = ((1 << x) - 1) & ((1 << 64) - 1)
+         mask_b = ((1 << y) - 1) & ((1 << 64) - 1)
+     elif x == y:
+         return 1 << x
+     else:
+         x = x+1
+         mask_a = ((1 << x) - 1) & ((1 << 64) - 1)
+         mask_b = (~((1 << y) - 1)) & ((1 << 64) - 1)
+     return mask_a ^ mask_b
+
+
 uint_xlen_t bmset(RS, RB, sh)
 {
     int shamt = RB & (XLEN - 1);
-- 
2.30.2