pfv: add gpr_width parameter to explore designs with 32-bit GPRs.

power_fv/check/insn/__init__.py

@@ -28,7 +28,13 @@ class InsnCheck(PowerFVCheck, metaclass=InsnCheckMeta):
     def __init__(self, *, depth, skip, core, **kwargs):
         super().__init__(depth=depth, skip=skip, core=core, **kwargs)
         self.insn = self.insn_cls()
-        self.spec = self.spec_cls(self.insn, mem_aligned=self.dut.pfv.mem_aligned, muldiv_altops=self.dut.pfv.muldiv_altops)
+        self.spec = self.spec_cls(
+            insn              = self.insn,
+            gpr_width         = self.dut.pfv.gpr_width,
+            mem_aligned       = self.dut.pfv.mem_aligned,
+            illegal_insn_heai = self.dut.pfv.illegal_insn_heai,
+            muldiv_altops     = self.dut.pfv.muldiv_altops,
+        )
 
     def testbench(self):
         return InsnTestbench(self)
@@ -136,6 +142,7 @@ class _GPRFileTest(Elaboratable):
     def __init__(self, check, *, port):
         self._dut   = getattr(check.dut .pfv, port)
         self._spec  = getattr(check.spec.pfv, port)
+        self._width = check.dut.pfv.gpr_width
 
         self.valid = Record([
             ("read" , [("index", 1), ("r_stb", 1)]),
@@ -148,6 +155,10 @@ class _GPRFileTest(Elaboratable):
         dut  = Record.like(self._dut )
         spec = Record.like(self._spec)
 
+        def gpr_equal(a, b):
+            mask = Const(2**self._width - 1, self._width)
+            return a & mask == b & mask
+
         m.d.comb += [
             dut .eq(self._dut ),
             spec.eq(self._spec),
@@ -159,7 +170,7 @@ class _GPRFileTest(Elaboratable):
             # The DUT and the spec must write the same value to the same GPR.
             self.valid.write.index .eq(spec.w_stb.implies(dut.index == spec.index)),
             self.valid.write.w_stb .eq(spec.w_stb == dut.w_stb),
-            self.valid.write.w_data.eq(spec.w_stb.implies(dut.w_data == spec.w_data)),
+            self.valid.write.w_data.eq(spec.w_stb.implies(gpr_equal(dut.w_data, spec.w_data))),
         ]
 
         return m

power_fv/pfv.py

@@ -106,6 +106,9 @@ class Interface(Record):
     The following parameters describe implementation-specific behavior. They do not affect the
     layout of this interface.
 
+    gpr_width : int
+        General-purpose register width. Either 32 or 64. Compliance with Power ISA versions above
+        v2.7B requires 64-bit wide GPRs.
     mem_aligned : bool
         If ``True``, an Alignment interrupt is expected if the effective address of a Load/Store
         operation is not aligned to its operand; ``mem.addr`` is also expected to be aligned to
@@ -215,8 +218,12 @@ class Interface(Record):
     srr1 : Record(:func:`reg_port_layout`)
         Save/Restore Register 1 access.
     """
-    def __init__(self, *, mem_aligned=False, illegal_insn_heai=False, muldiv_altops=False,
+    def __init__(self, *, gpr_width=64, mem_aligned=False, illegal_insn_heai=False,
-                 name=None, src_loc_at=0):
+                 muldiv_altops=False, name=None, src_loc_at=0):
+        if gpr_width not in (32, 64):
+            raise ValueError("GPR width must be 32 or 64, not {!r}".format(gpr_width))
+
+        self.gpr_width         = gpr_width
         self.mem_aligned       = bool(mem_aligned)
         self.illegal_insn_heai = bool(illegal_insn_heai)
         self.muldiv_altops     = bool(muldiv_altops)