From 7815f7295a1a9feb0b86f127cd9a9dd96939c461 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Mon, 20 Jun 2022 01:18:36 +0100
Subject: [PATCH] add set before first demo

---
 openpower/sv/sbf.py | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 openpower/sv/sbf.py

diff --git a/openpower/sv/sbf.py b/openpower/sv/sbf.py
new file mode 100644
index 000000000..1885a3929
--- /dev/null
+++ b/openpower/sv/sbf.py
@@ -0,0 +1,35 @@
+def sbf(RA, mask=None):
+    RT = RA if mask is not None else 0
+    i = 0
+    # start setting if no predicate or if 1st predicate bit set
+    setting_mode = mask is None
+    while i < 16:
+        bit = 1<<i
+        if not setting_mode and mask is not None and (mask & bit):
+            setting_mode = True # back into "setting" mode
+        if setting_mode:
+            if RA & bit: # found a bit in rs1: stop setting RT
+                setting_mode = False
+            else:
+                RT |= bit
+        i += 1
+    return RT
+
+if __name__ == '__main__':
+     m  = 0b11000011
+     v3 = 0b10010100 # vmsbf.m v2, v3
+     v2 = 0b01000011 # v2
+     RT = sbf(v3, m)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b10010100 # vmsbf.m v2, v3
+     v2 = 0b00000011 # v2 contents
+     RT = sbf(v3)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b10010101 # vmsbf.m v2, v3
+     v2 = 0b00000000 # v2
+     RT = sbf(v3)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b00000000 # vmsbf.m v2, v3
+     v2 = 0b11111111 # v2
+     RT = sbf(v3)
+     print(bin(v3), bin(v2), bin(RT))
-- 
2.30.2