From: Michael Nolan <mtnolan2640@gmail.com>
Date: Sat, 16 May 2020 18:05:55 +0000 (-0400)
Subject: Implement mtocrf (which isn't different from mtcrf?)
X-Git-Tag: div_pipeline~1129
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f755665f4a19929675065830cdb16551b565b84c;p=soc.git

Implement mtocrf (which isn't different from mtcrf?)
---

diff --git a/src/soc/cr/main_stage.py b/src/soc/cr/main_stage.py
index 4a27fcd4..1552c4b1 100644
--- a/src/soc/cr/main_stage.py
+++ b/src/soc/cr/main_stage.py
@@ -65,6 +65,13 @@ class CRMainStage(PipeModBase):
         # There's no field, just have to grab it directly from the insn
         comb += lut.eq(self.i.ctx.op.insn[6:10])
 
+
+        # Ugh. mtocrf and mtcrf have one random bit differentiating
+        # them. This bit is not in any particular field, so this
+        # extracts that bit from the instruction
+        move_one = Signal(reset_less=True)
+        comb += move_one.eq(self.i.ctx.op.insn[20])
+
         with m.Switch(op.insn_type):
             with m.Case(InternalOp.OP_MCRF):
                 # MCRF copies the 4 bits of crA to crB (for instance
@@ -108,6 +115,7 @@ class CRMainStage(PipeModBase):
                 fxm = Signal(xfx_fields['FXM'][0:-1].shape())
                 comb += fxm.eq(xfx_fields['FXM'][0:-1])
 
+                # mtcrf
                 mask = Signal(32, reset_less=True)
 
                 for i in range(8):
@@ -115,6 +123,7 @@ class CRMainStage(PipeModBase):
 
                 comb += cr_output.eq((self.i.a[0:32] & mask) |
                                      (self.i.cr & ~mask))
+                    
 
         comb += self.o.cr.eq(cr_output)
         comb += self.o.ctx.eq(self.i.ctx)
diff --git a/src/soc/cr/test/test_pipe_caller.py b/src/soc/cr/test/test_pipe_caller.py
index 42133771..ccb41a76 100644
--- a/src/soc/cr/test/test_pipe_caller.py
+++ b/src/soc/cr/test/test_pipe_caller.py
@@ -92,7 +92,15 @@ class CRTestCase(FHDLTestCase):
             initial_regs[2] = random.randint(0, (1<<32)-1)
             self.run_tst_program(Program(lst), initial_regs=initial_regs,
                                  initial_cr=cr)
-        
+    def test_mtocrf(self):
+        for i in range(20):
+            mask = 1<<random.randint(0, 7)
+            lst = [f"mtocrf {mask}, 2"]
+            cr = random.randint(0, (1<<32)-1)
+            initial_regs = [0] * 32
+            initial_regs[2] = random.randint(0, (1<<32)-1)
+            self.run_tst_program(Program(lst), initial_regs=initial_regs,
+                                 initial_cr=cr)
 
     def test_ilang(self):
         rec = CompALUOpSubset()