From 527efabfbe08f5ce2ea81b4bf26d8b194eb109b5 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Tue, 17 May 2022 12:56:52 +0100
Subject: [PATCH] add first exploration of 4-wide AOI

---
 openpower/sv/grevlut_v2.py | 110 +++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 openpower/sv/grevlut_v2.py

diff --git a/openpower/sv/grevlut_v2.py b/openpower/sv/grevlut_v2.py
new file mode 100644
index 000000000..9da592801
--- /dev/null
+++ b/openpower/sv/grevlut_v2.py
@@ -0,0 +1,110 @@
+
+def andor(imm, a, b, ainv, binv):
+    inbits = [a, b, ainv, binv]
+    res = 0
+    for i in range(4):
+        if ((imm >> i) & 0b1) & inbits[i]:
+            res = 1
+    return res
+
+def dorow(imm8, step_i, chunk_size):
+    step_o = 0
+    for j in range(64):
+        if (j&chunk_size) == 0:
+           imm = (imm8 & 0b1111)
+        else:
+           imm = (imm8>>4)
+        a = (step_i>>j)&1
+        b = (step_i>>(j ^ chunk_size))&1
+        res = andor(imm, a, b, ~a, ~b)
+        #print(j, bin(imm), a, b, res)
+        step_o |= (res<<j)
+    #print ("  ", chunk_size, bin(step_o))
+    return step_o
+
+def grevlut64(RA, RB, imm, iv):
+    x = 0
+    if RA is None: # RA=0
+        x = 0x5555555555555555
+    else:
+        x = RA
+    if (iv): x = ~x;
+    shamt = RB & 63;
+    #print (bin(shamt), bin(63))
+    for i in range(6):
+        step = 1<<i
+        if shamt & step:
+            x = dorow(imm, x, step)
+    return x & ((1<<64)-1)
+
+
+if __name__ == '__main__':
+    imm = 0b0110
+    a = 1
+    b = 0
+    print (andor(imm, a, b, ~a, ~b))
+
+    # answer: 8888888...
+    RB = 0b0000
+    imm = 0b1100_0110
+    x = grevlut64(None, RB, imm, 1)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+
+    # answer: 8888888...
+    RB = 0b000001
+    imm = 0b10001000
+    x = grevlut64(None, RB, imm, 1)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+
+    exit(0)
+
+    # answer: 80808080...
+    RB = 0b00110
+    imm = 0b11000110
+    x = grevlut64(None, RB, imm, 1)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+
+    # answer: 80008000...
+    RB = 0b01110
+    imm = 0b11000110
+    x = grevlut64(None, RB, imm, 1)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
+    # answer: 01010101...
+    RB = 0b00110
+    imm = 0b01101100
+    x = grevlut64(None, RB, imm, 0)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+
+    # answer: 00010001...
+    RB = 0b01110
+    imm = 0b01101100
+    x = grevlut64(None, RB, imm, 0)
+    print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
+    for RB in range(64):
+        imm = 0b11000110
+        x = grevlut64(None, RB, imm, 1)
+        print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
+    for RB in range(64):
+        imm = 0b01101100
+        x = grevlut64(None, RB, imm, 0)
+        print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
+    for RB in range(64):
+        imm = 0b10011010
+        x = grevlut64(None, RB, imm, 1)
+        print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
+    for RB in range(64):
+        imm = 0b01011010
+        x = grevlut64(None, RB, imm, 1)
+        print ("grevlut", bin(RB), bin(imm), hex(x), "\n", bin(x))
+    print()
+
-- 
2.30.2