From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Wed, 22 Jun 2022 11:51:11 +0000 (+0100)
Subject: add experimental bmask demo
X-Git-Tag: opf_rfc_ls005_v1~1602
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9d20ba215073133be57d80c8fcfbf4db564e6302;p=libreriscv.git

add experimental bmask demo
---

diff --git a/openpower/sv/bmask.py b/openpower/sv/bmask.py
new file mode 100644
index 000000000..4b431837c
--- /dev/null
+++ b/openpower/sv/bmask.py
@@ -0,0 +1,47 @@
+def bmask(mode, RA, RB=None, zero=False):
+    RT = RA if RB is not None and not zero else 0
+    mask = RB if RB is not None else 0xffffffffffffffff
+    a1 = RA if mode&1 else ~RA
+    mode2 = (mode >> 1) & 0b11
+    if mode2 == 0:
+        a2 = -RA
+    if mode2 == 1:
+        a2 = RA-1
+    if mode2 == 2:
+        a2 = RA+1
+    if mode2 == 3:
+        a2 = ~(RA+1)
+    a1 = a1 & mask
+    a2 = a2 & mask
+    mode3 = (mode >> 3) & 0b11
+    if mode3 == 0:
+         RT = a1 | a2
+    if mode3 == 1:
+         RT = a1 & a2
+    if mode3 == 2:
+         RT = a1 ^ a2
+    return RT & mask
+
+SBF = 0b001110
+
+if __name__ == '__main__':
+   for SBF in range(32):
+     print("mode", bin(SBF))
+     m  = 0b11000011
+     v3 = 0b10010100 # vmsbf.m v2, v3
+     v2 = 0b01000011 # v2
+     RT = bmask(SBF, v3, m, zero=True)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b10010100 # vmsbf.m v2, v3
+     v2 = 0b00000011 # v2 contents
+     RT = bmask(SBF, v3)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b10010101 # vmsbf.m v2, v3
+     v2 = 0b00000000 # v2
+     RT = bmask(SBF, v3)
+     print(bin(v3), bin(v2), bin(RT))
+     v3 = 0b00000000 # vmsbf.m v2, v3
+     v2 = 0b11111111 # v2
+     RT = bmask(SBF, v3)
+     print(bin(v3), bin(v2), bin(RT))
+     print()