From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 4 Apr 2019 07:29:53 +0000 (+0100)
Subject: use ObjectProxy in get_op
X-Git-Tag: ls180-24jan2020~1348
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=89868b493be48969ffa5d2c0a2625a5aa3cabdcf;p=ieee754fpu.git

use ObjectProxy in get_op
---

diff --git a/src/add/fadd_state.py b/src/add/fadd_state.py
index 343f13ed..79a8723d 100644
--- a/src/add/fadd_state.py
+++ b/src/add/fadd_state.py
@@ -7,6 +7,8 @@ from nmigen.cli import main, verilog
 
 from fpbase import FPNumIn, FPNumOut, FPOp, Overflow, FPBase
 
+from singlepipe import eq
+
 
 class FPADD(FPBase):
 
@@ -49,13 +51,15 @@ class FPADD(FPBase):
             # gets operand a
 
             with m.State("get_a"):
-                self.get_op(m, self.in_a, a, "get_b")
+                res = self.get_op(m, self.in_a, a, "get_b")
+                m.d.sync += eq([a, self.in_a.ack], res)
 
             # ******
             # gets operand b
 
             with m.State("get_b"):
-                self.get_op(m, self.in_b, b, "special_cases")
+                res = self.get_op(m, self.in_b, b, "special_cases")
+                m.d.sync += eq([b, self.in_b.ack], res)
 
             # ******
             # special cases: NaNs, infs, zeros, denormalised
diff --git a/src/add/fpbase.py b/src/add/fpbase.py
index dc2c9020..b15c21ca 100644
--- a/src/add/fpbase.py
+++ b/src/add/fpbase.py
@@ -7,6 +7,9 @@ from math import log
 from operator import or_
 from functools import reduce
 
+from pipeline import ObjectProxy
+
+
 class MultiShiftR:
 
     def __init__(self, width):
@@ -353,6 +356,22 @@ class FPNumIn(FPNumBase):
         self.latch_in = Signal()
         self.op = op
 
+    def decode2(self, m):
+        """ decodes a latched value into sign / exponent / mantissa
+
+            bias is subtracted here, from the exponent.  exponent
+            is extended to 10 bits so that subtract 127 is done on
+            a 10-bit number
+        """
+        v = self.v
+        args = [0] * self.m_extra + [v[0:self.e_start]] # pad with extra zeros
+        #print ("decode", self.e_end)
+        res = ObjectProxy(m, pipemode=False)
+        res.m = Cat(*args)                             # mantissa
+        res.e = v[self.e_start:self.e_end] - self.P127 # exp
+        res.s = v[-1]                                  # sign
+        return res
+
     def decode(self, v):
         """ decodes a latched value into sign / exponent / mantissa
 
@@ -509,15 +528,15 @@ class FPBase:
             when both stb and ack are 1.
             acknowledgement is sent by setting ack to ZERO.
         """
+        res = v.decode2(m)
+        ack = Signal()
         with m.If((op.ack) & (op.stb)):
             m.next = next_state
-            m.d.sync += [
-                # op is latched in from FPNumIn class on same ack/stb
-                v.decode(op.v),
-                op.ack.eq(0)
-            ]
+            # op is latched in from FPNumIn class on same ack/stb
+            m.d.comb += ack.eq(0)
         with m.Else():
-            m.d.sync += op.ack.eq(1)
+            m.d.comb += ack.eq(1)
+        return [res, ack]
 
     def denormalise(self, m, a):
         """ denormalises a number.  this is probably the wrong name for