# Copyright (C) Jonathan P Dawson 2013
# 2013-12-12
-from nmigen import Module, Signal, Cat, Mux, Array, Const
-from nmigen.lib.coding import PriorityEncoder
+from nmigen import Module, Signal, Cat, Const
from nmigen.cli import main, verilog
from math import log
-from fpbase import FPNumIn, FPNumOut, FPOp, Overflow, FPBase, FPNumBase
-from fpbase import MultiShiftRMerge, Trigger
-from singlepipe import (ControlBase, StageChain, UnbufferedPipeline,
- PassThroughStage)
-from multipipe import CombMuxOutPipe
-from multipipe import PriorityCombMuxInPipe
+from fpbase import FPNumDecode
+from singlepipe import SimpleHandshake, StageChain
from fpbase import FPState, FPID
from fpcommon.getop import FPADDBaseData
-from fpcommon.denorm import (FPSCData, FPAddDeNormMod, FPAddDeNorm)
+from fpcommon.denorm import (FPSCData, FPAddDeNormMod)
class FPAddSpecialCasesMod:
m.submodules.sc_out_z = self.o.z
# decode: XXX really should move to separate stage
- a1 = FPNumIn(None, self.width)
- b1 = FPNumIn(None, self.width)
+ a1 = FPNumDecode(None, self.width)
+ b1 = FPNumDecode(None, self.width)
m.submodules.sc_decode_a = a1
m.submodules.sc_decode_b = b1
- m.d.comb += [a1.decode(self.i.a),
- b1.decode(self.i.b),
+ m.d.comb += [a1.v.eq(self.i.a),
+ b1.v.eq(self.i.b),
+ self.o.a.eq(a1),
+ self.o.b.eq(b1)
]
- s_nomatch = Signal()
+ s_nomatch = Signal(reset_less=True)
m.d.comb += s_nomatch.eq(a1.s != b1.s)
- m_match = Signal()
+ m_match = Signal(reset_less=True)
m.d.comb += m_match.eq(a1.m == b1.m)
+ e_match = Signal(reset_less=True)
+ m.d.comb += e_match.eq(a1.e == b1.e)
+
+ aeqmb = Signal(reset_less=True)
+ m.d.comb += aeqmb.eq(s_nomatch & m_match & e_match)
+
+ abz = Signal(reset_less=True)
+ m.d.comb += abz.eq(a1.is_zero & b1.is_zero)
+
+ abnan = Signal(reset_less=True)
+ m.d.comb += abnan.eq(a1.is_nan | b1.is_nan)
+
+ bexp128s = Signal(reset_less=True)
+ m.d.comb += bexp128s.eq(b1.exp_128 & s_nomatch)
+
# if a is NaN or b is NaN return NaN
- with m.If(a1.is_nan | b1.is_nan):
+ with m.If(abnan):
m.d.comb += self.o.out_do_z.eq(1)
m.d.comb += self.o.z.nan(0)
m.d.comb += self.o.out_do_z.eq(1)
m.d.comb += self.o.z.inf(a1.s)
# if a is inf and signs don't match return NaN
- with m.If(b1.exp_128 & s_nomatch):
+ with m.If(bexp128s):
m.d.comb += self.o.z.nan(0)
# if b is inf return inf
m.d.comb += self.o.z.inf(b1.s)
# if a is zero and b zero return signed-a/b
- with m.Elif(a1.is_zero & b1.is_zero):
+ with m.Elif(abz):
m.d.comb += self.o.out_do_z.eq(1)
m.d.comb += self.o.z.create(a1.s & b1.s, b1.e, b1.m[3:-1])
m.d.comb += self.o.z.create(a1.s, a1.e, a1.m[3:-1])
# if a equal to -b return zero (+ve zero)
- with m.Elif(s_nomatch & m_match & (a1.e == b1.e)):
+ with m.Elif(aeqmb):
m.d.comb += self.o.out_do_z.eq(1)
m.d.comb += self.o.z.zero(0)
# Denormalised Number checks next, so pass a/b data through
with m.Else():
m.d.comb += self.o.out_do_z.eq(0)
- m.d.comb += self.o.a.eq(a1)
- m.d.comb += self.o.b.eq(b1)
m.d.comb += self.o.oz.eq(self.o.z.v)
m.d.comb += self.o.mid.eq(self.i.mid)
m.next = "denormalise"
-class FPAddSpecialCasesDeNorm(FPState, UnbufferedPipeline):
+class FPAddSpecialCasesDeNorm(FPState, SimpleHandshake):
""" special cases: NaNs, infs, zeros, denormalised
NOTE: some of these are unique to add. see "Special Operations"
https://steve.hollasch.net/cgindex/coding/ieeefloat.html
FPState.__init__(self, "special_cases")
self.width = width
self.id_wid = id_wid
- UnbufferedPipeline.__init__(self, self) # pipe is its own stage
+ SimpleHandshake.__init__(self, self) # pipe is its own stage
self.out = self.ospec()
def ispec(self):