From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Fri, 26 Aug 2022 18:39:05 +0000 (+0100)
Subject: initialise overflow to zero in setvl, unconditionally.
X-Git-Tag: sv_maxu_works-initial~79
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=80ad71609c45ad9bb4f93c6836487dc0d00f584f;p=openpower-isa.git

initialise overflow to zero in setvl, unconditionally.
add two new CTR-mode/Rc=1 setvl. tests, to confirm that overflow
does/does-not occur correctly when CTR is used as input to set VL
---

diff --git a/openpower/isa/simplev.mdwn b/openpower/isa/simplev.mdwn
index 7d60e901..e177b04d 100644
--- a/openpower/isa/simplev.mdwn
+++ b/openpower/isa/simplev.mdwn
@@ -26,12 +26,12 @@ SVL-Form
 
 Pseudo-code:
 
+    overflow <- 0b0
     if (vf & (¬vs) & ¬(ms)) = 1 then
         step <- SVSTATE_NEXT(SVi, 0b0)
         if _RT != 0 then
            GPR(_RT) <- [0]*57 || step
     else
-        overflow <- 0b0
         VLimm <- SVi + 1
         # set or get MVL
         if ms = 1 then MVL <- VLimm[0:6]
diff --git a/src/openpower/decoder/isa/test_caller_setvl.py b/src/openpower/decoder/isa/test_caller_setvl.py
index c6ddffcd..0f25218b 100644
--- a/src/openpower/decoder/isa/test_caller_setvl.py
+++ b/src/openpower/decoder/isa/test_caller_setvl.py
@@ -367,6 +367,40 @@ class DecoderTestCase(FHDLTestCase):
             self.assertEqual(CR0[CRFields.GT], 0)
             self.assertEqual(CR0[CRFields.SO], 0)
 
+    def test_setvl_ctr_1_rc1(self):
+        """setvl CTR mode, with Rc=1, testing if VL and MVL are over-ridden
+        and CR0 set correctly
+        """
+        lst = SVP64Asm(["setvl. 1, 0, 10, 0, 1, 1",
+                        ])
+        lst = list(lst)
+
+        # SVSTATE (in this case, VL=2), want to see if these get changed
+        svstate = SVP64State()
+        svstate.vl = 2 # VL
+        svstate.maxvl = 2 # MAXVL
+        print ("SVSTATE", bin(svstate.asint()))
+        sprs = {'CTR': 5,
+               }
+
+        with Program(lst, bigendian=False) as program:
+            sim = self.run_tst_program(program, svstate=svstate,
+                                       initial_sprs=sprs)
+            print ("SVSTATE after", bin(sim.svstate.asint()))
+            print ("        vl", bin(sim.svstate.vl))
+            print ("        mvl", bin(sim.svstate.maxvl))
+            self.assertEqual(sim.svstate.vl, 5)
+            self.assertEqual(sim.svstate.maxvl, 10)
+            print("      gpr1", sim.gpr(1))
+            self.assertEqual(sim.gpr(1), SelectableInt(5, 64))
+
+            CR0 = sim.crl[0]
+            print("      CR0", bin(CR0.get_range().value))
+            self.assertEqual(CR0[CRFields.EQ], 0)
+            self.assertEqual(CR0[CRFields.LT], 0)
+            self.assertEqual(CR0[CRFields.GT], 1)
+            self.assertEqual(CR0[CRFields.SO], 0)
+
     def test_setvl_ctr_1(self):
         """setvl CTR mode, testing if VL and MVL are over-ridden
         """
@@ -393,6 +427,47 @@ class DecoderTestCase(FHDLTestCase):
             print("      gpr1", sim.gpr(1))
             self.assertEqual(sim.gpr(1), SelectableInt(5, 64))
 
+            CR0 = sim.crl[0]
+            print("      CR0", bin(CR0.get_range().value))
+            self.assertEqual(CR0[CRFields.EQ], 0)
+            self.assertEqual(CR0[CRFields.LT], 0)
+            self.assertEqual(CR0[CRFields.GT], 0)
+            self.assertEqual(CR0[CRFields.SO], 0)
+
+    def test_setvl_ctr_2_rc1(self):
+        """setvl Rc=1, CTR large, testing if VL and MVL are over-ridden,
+        check if CR0.SO gets set
+        """
+        lst = SVP64Asm(["setvl. 1, 0, 10, 0, 1, 1",
+                        ])
+        lst = list(lst)
+
+        # SVSTATE (in this case, VL=2), want to see if these get changed
+        svstate = SVP64State()
+        svstate.vl = 2 # VL
+        svstate.maxvl = 2 # MAXVL
+        print ("SVSTATE", bin(svstate.asint()))
+        sprs = {'CTR': 0x1000000000,
+               }
+
+        with Program(lst, bigendian=False) as program:
+            sim = self.run_tst_program(program, svstate=svstate,
+                                       initial_sprs=sprs)
+            print ("SVSTATE after", bin(sim.svstate.asint()))
+            print ("        vl", bin(sim.svstate.vl))
+            print ("        mvl", bin(sim.svstate.maxvl))
+            self.assertEqual(sim.svstate.vl, 10)
+            self.assertEqual(sim.svstate.maxvl, 10)
+            print("      gpr1", sim.gpr(1))
+            self.assertEqual(sim.gpr(1), SelectableInt(10, 64))
+
+            CR0 = sim.crl[0]
+            print("      CR0", bin(CR0.get_range().value))
+            self.assertEqual(CR0[CRFields.EQ], 0)
+            self.assertEqual(CR0[CRFields.LT], 0)
+            self.assertEqual(CR0[CRFields.GT], 1)
+            self.assertEqual(CR0[CRFields.SO], 1)
+
     def test_setvl_ctr_2(self):
         """setvl CTR large, testing if VL and MVL are over-ridden
         """