remove use of out_do_z, use Mux instead of m.If/Else

[ieee754fpu.git] / src / ieee754 / fpcommon / denorm.py

diff --git a/src/ieee754/fpcommon/denorm.py b/src/ieee754/fpcommon/denorm.py
index 7f45b6b779e4551cca28f6e9f379c3c91a976e09..350f413ede9858ae490059f6709b3454ea8a7f1e 100644 (file)
--- a/src/ieee754/fpcommon/denorm.py
+++ b/src/ieee754/fpcommon/denorm.py
@@ -1,110 +1,56 @@
-# IEEE Floating Point Adder (Single Precision)
-# Copyright (C) Jonathan P Dawson 2013
-# 2013-12-12
+"""IEEE754 Floating Point Library
 
-from nmigen import Module, Signal, Elaboratable
-from nmigen.cli import main, verilog
-from math import log
-
-from ieee754.fpcommon.fpbase import FPNumIn, FPNumOut, FPNumBaseRecord
-from ieee754.fpcommon.fpbase import FPState, FPNumBase
-
-
-class FPSCData:
+Copyright (C) 2019 Luke Kenneth Casson Leighton <lkcl@lkcl.net>
 
-    def __init__(self, width, id_wid, m_extra=True):
-        self.a = FPNumBaseRecord(width, m_extra)
-        self.b = FPNumBaseRecord(width, m_extra)
-        self.z = FPNumBaseRecord(width, False)
-        self.oz = Signal(width, reset_less=True)
-        self.out_do_z = Signal(reset_less=True)
-        self.mid = Signal(id_wid, reset_less=True)
+"""
 
-    def __iter__(self):
-        yield from self.a
-        yield from self.b
-        yield from self.z
-        yield self.oz
-        yield self.out_do_z
-        yield self.mid
+from nmigen import Module, Mux
+from nmigen.cli import main, verilog
+from math import log
 
-    def eq(self, i):
-        return [self.z.eq(i.z), self.out_do_z.eq(i.out_do_z), self.oz.eq(i.oz),
-                self.a.eq(i.a), self.b.eq(i.b), self.mid.eq(i.mid)]
+from nmutil.pipemodbase import PipeModBase
+from ieee754.fpcommon.fpbase import FPNumBase
+from ieee754.fpcommon.pscdata import FPSCData
 
 
-class FPAddDeNormMod(FPState, Elaboratable):
+class FPAddDeNormMod(PipeModBase):
 
-    def __init__(self, width, id_wid, m_extra=True):
-        self.width = width
-        self.id_wid = id_wid
+    def __init__(self, pspec, m_extra):
         self.m_extra = m_extra
-        self.i = self.ispec()
-        self.o = self.ospec()
+        super().__init__(pspec, "denormalise")
 
     def ispec(self):
-        return FPSCData(self.width, self.id_wid, self.m_extra)
+        return FPSCData(self.pspec, self.m_extra)
 
     def ospec(self):
-        return FPSCData(self.width, self.id_wid, self.m_extra)
-
-    def process(self, i):
-        return self.o
-
-    def setup(self, m, i):
-        """ links module to inputs and outputs
-        """
-        m.submodules.denormalise = self
-        m.d.comb += self.i.eq(i)
+        return FPSCData(self.pspec, self.m_extra)
 
     def elaborate(self, platform):
         m = Module()
+        comb = m.d.comb
+
         m.submodules.denorm_in_a = in_a = FPNumBase(self.i.a)
         m.submodules.denorm_in_b = in_b = FPNumBase(self.i.b)
-        #m.submodules.denorm_out_a = self.o.a
-        #m.submodules.denorm_out_b = self.o.b
-        #m.submodules.denorm_out_z = self.o.z
 
-        with m.If(~self.i.out_do_z):
-            # XXX hmmm, don't like repeating identical code
-            m.d.comb += self.o.a.eq(self.i.a)
-            with m.If(in_a.exp_n127):
-                m.d.comb += self.o.a.e.eq(self.i.a.N126) # limit a exponent
-            with m.Else():
-                m.d.comb += self.o.a.m[-1].eq(1) # set top mantissa bit
-
-            m.d.comb += self.o.b.eq(self.i.b)
-            with m.If(in_b.exp_n127):
-                m.d.comb += self.o.b.e.eq(self.i.b.N126) # limit a exponent
-            with m.Else():
-                m.d.comb += self.o.b.m[-1].eq(1) # set top mantissa bit
-
-        m.d.comb += self.o.mid.eq(self.i.mid)
-        m.d.comb += self.o.z.eq(self.i.z)
-        m.d.comb += self.o.out_do_z.eq(self.i.out_do_z)
-        m.d.comb += self.o.oz.eq(self.i.oz)
+        # XXX hmmm, don't like repeating identical code
+        comb += self.o.a.eq(self.i.a)
+        ae = self.i.a.e
+        am = self.i.a.m
+        # either limit exponent, or set top mantissa bit
+        comb += self.o.a.e.eq(Mux(in_a.exp_n127, self.i.a.N126, ae))
+        comb += self.o.a.m[-1].eq(Mux(in_a.exp_n127, am[-1], 1))
+
+        # XXX code now repeated for b
+        comb += self.o.b.eq(self.i.b)
+        be = self.i.b.e
+        bm = self.i.b.m
+        # either limit exponent, or set top mantissa bit
+        comb += self.o.b.e.eq(Mux(in_b.exp_n127, self.i.b.N126, be))
+        comb += self.o.b.m[-1].eq(Mux(in_b.exp_n127, bm[-1], 1))
+
+        comb += self.o.ctx.eq(self.i.ctx)
+        comb += self.o.z.eq(self.i.z)
+        comb += self.o.out_do_z.eq(self.i.out_do_z)
+        comb += self.o.oz.eq(self.i.oz)
 
         return m
-
-
-class FPAddDeNorm(FPState):
-
-    def __init__(self, width, id_wid):
-        FPState.__init__(self, "denormalise")
-        self.mod = FPAddDeNormMod(width)
-        self.out_a = FPNumBaseRecord(width)
-        self.out_b = FPNumBaseRecord(width)
-
-    def setup(self, m, i):
-        """ links module to inputs and outputs
-        """
-        self.mod.setup(m, i)
-
-        m.d.sync += self.out_a.eq(self.mod.out_a)
-        m.d.sync += self.out_b.eq(self.mod.out_b)
-
-    def action(self, m):
-        # Denormalised Number checks
-        m.next = "align"
-
-