From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Fri, 30 Dec 2022 13:41:49 +0000 (+0000)
Subject: add rollover mem test, store "rolls over" a 64-bit boundary
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=245194ee2937392c922828024757fed399f31b43;p=openpower-isa.git

add rollover mem test, store "rolls over" a 64-bit boundary
---

diff --git a/src/openpower/decoder/isa/mem.py b/src/openpower/decoder/isa/mem.py
index 23e2c07e..8b3e0563 100644
--- a/src/openpower/decoder/isa/mem.py
+++ b/src/openpower/decoder/isa/mem.py
@@ -147,10 +147,20 @@ class Mem:
         if swap:
             v = swap_order(v, width)
         # not misaligned: pass through to Mem._st but we've swapped already
-        if remainder & (width - 1) == 0:
+        misaligned = remainder & (width - 1)
+        if misaligned == 0:
             return self._st(addr, v, width, swap=False)
         shifter, mask = self._get_shifter_mask(width, remainder)
-        print ("mask", hex(shifter), hex(mask))
+        # split into two halves. lower first
+        maxmask = (1 << (self.bytes_per_word)*8) - 1
+        val1 = ((v << shifter) & maxmask) >> shifter
+        self._st(addr+misaligned, val1,
+                 width=width-misaligned, swap=False)
+        # now upper
+        val2 = v >> ((width-misaligned)*8)
+        print ("v, val2", hex(v), hex(val2))
+        self._st(addr+self.bytes_per_word, val2,
+                 width=width-misaligned, swap=False)
 
     def __call__(self, addr, sz):
         val = self.ld(addr.value, sz, swap=False)
diff --git a/src/openpower/decoder/isa/test_mem.py b/src/openpower/decoder/isa/test_mem.py
index b7734449..9a5423af 100644
--- a/src/openpower/decoder/isa/test_mem.py
+++ b/src/openpower/decoder/isa/test_mem.py
@@ -16,13 +16,13 @@ class TestMem(unittest.TestCase):
         log ("dict", d)
         self.assertEqual(d, [(0, 0x1234567800000000)])
 
-    def test_mem_misalign_st(self):
+    def test_mem_misalign_st_rollover(self):
         m = Mem(row_bytes=8, initial_mem={}, misaligned_ok=True)
-        m.st(4, 0x912345678, width=8, swap=False)
+        m.st(6, 0x912345678, width=8, swap=False)
         d = m.dump()
         log ("dict", d)
-        self.assertEqual(d, [(0, 0x1234567800000000),
-                              8, 0x0000000000000009])
+        self.assertEqual(d, [(0, 0x5678000000000000),
+                             (8, 0x0000000000091234)])
 
 
 if __name__ == '__main__':