From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 9 Jul 2020 19:54:09 +0000 (+0100)
Subject: ha ha very funny.  pipelines being pipelines, you have to wait for them
X-Git-Tag: div_pipeline~124
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=4dc4160e6c3545785c32a21fdfd7e30826ee3224;p=soc.git

ha ha very funny.  pipelines being pipelines, you have to wait for them
just as with MUL, it was necessary to set the "valid" signal for
only one cycle otherwise spurious output is created
---

diff --git a/src/soc/fu/div/test/test_pipe_caller.py b/src/soc/fu/div/test/test_pipe_caller.py
index 978c1b9b..4b7fea86 100644
--- a/src/soc/fu/div/test/test_pipe_caller.py
+++ b/src/soc/fu/div/test/test_pipe_caller.py
@@ -111,6 +111,16 @@ class DIVTestCase(FHDLTestCase):
         initial_regs[2] = 0xe730c2eed6cc8dd7
         self.run_tst_program(Program(lst), initial_regs)
 
+    def test_5_regression(self):
+        lst = ["divw 3, 1, 2",
+               "divwo. 6, 4, 5"]
+        initial_regs = [0] * 32
+        initial_regs[1] = 0x1c4e6c2f3aa4a05c
+        initial_regs[2] = 0xe730c2eed6cc8dd7
+        initial_regs[4] = 0x1b8e32f2458746af
+        initial_regs[5] = 0x6b8aee2ccf7d62e9
+        self.run_tst_program(Program(lst), initial_regs)
+
     def test_rand_divw(self):
         insns = ["divw", "divw.", "divwo", "divwo."]
         for i in range(40):
@@ -125,7 +135,7 @@ class DIVTestCase(FHDLTestCase):
         pspec = DIVPipeSpec(id_wid=2)
         alu = DIVBasePipe(pspec)
         vl = rtlil.convert(alu, ports=alu.ports())
-        with open("alu_pipeline.il", "w") as f:
+        with open("div_pipeline.il", "w") as f:
             f.write(vl)
 
 
@@ -147,7 +157,6 @@ class TestRunner(FHDLTestCase):
         m.submodules.alu = alu = DIVBasePipe(pspec)
 
         comb += alu.p.data_i.ctx.op.eq_from_execute1(pdecode2.e)
-        comb += alu.p.valid_i.eq(1)
         comb += alu.n.ready_i.eq(1)
         comb += pdecode2.dec.raw_opcode_in.eq(instruction)
         sim = Simulator(m)
@@ -162,6 +171,7 @@ class TestRunner(FHDLTestCase):
                                 test.mem, test.msr)
                 gen = program.generate_instructions()
                 instructions = list(zip(gen, program.assembly.splitlines()))
+                yield Settle()
 
                 index = sim.pc.CIA.value//4
                 while index < len(instructions):
@@ -182,7 +192,12 @@ class TestRunner(FHDLTestCase):
                     fn_unit = yield pdecode2.e.do.fn_unit
                     self.assertEqual(fn_unit, Function.DIV.value)
                     yield from set_alu_inputs(alu, pdecode2, sim)
+
+                    # set valid for one cycle, propagate through pipeline...
+                    yield alu.p.valid_i.eq(1)
                     yield
+                    yield alu.p.valid_i.eq(0)
+
                     opname = code.split(' ')[0]
                     yield from sim.call(opname)
                     index = sim.pc.CIA.value//4
@@ -194,6 +209,7 @@ class TestRunner(FHDLTestCase):
                     yield
 
                     yield from self.check_alu_outputs(alu, pdecode2, sim, code)
+                    yield Settle()
 
         sim.add_sync_process(process)
         with sim.write_vcd("div_simulator.vcd", "div_simulator.gtkw",
@@ -210,15 +226,6 @@ class TestRunner(FHDLTestCase):
         if rc:
             self.assertEqual(cridx, 0, code)
 
-        oe = yield dec2.e.do.oe.oe
-        oe_ok = yield dec2.e.do.oe.ok
-        if not oe or not oe_ok:
-            # if OE not enabled, XER SO and OV must correspondingly be false
-            so_ok = yield alu.n.data_o.xer_so.ok
-            ov_ok = yield alu.n.data_o.xer_ov.ok
-            self.assertEqual(so_ok, False, code)
-            self.assertEqual(ov_ok, False, code)
-
         sim_o = {}
         res = {}
 
@@ -241,6 +248,17 @@ class TestRunner(FHDLTestCase):
         ALUHelpers.check_xer_ov(self, res, sim_o, code)
         ALUHelpers.check_xer_so(self, res, sim_o, code)
 
+        oe = yield dec2.e.do.oe.oe
+        oe_ok = yield dec2.e.do.oe.ok
+        print ("oe, oe_ok", oe, oe_ok)
+        if not oe or not oe_ok:
+            # if OE not enabled, XER SO and OV must not be activated
+            so_ok = yield alu.n.data_o.xer_so.ok
+            ov_ok = yield alu.n.data_o.xer_ov.ok
+            print ("so, ov", so_ok, ov_ok)
+            self.assertEqual(ov_ok, False, code)
+            self.assertEqual(so_ok, False, code)
+
 
 if __name__ == "__main__":
     unittest.main(exit=False)