From b7e2f349661c0f5a3d474e1dd88eccdcd100264a Mon Sep 17 00:00:00 2001
From: David Harris <David_Harris@hmc.edu>
Date: Wed, 12 Jun 2024 03:59:55 -0700
Subject: [PATCH] shiftcorrection cleanup

---
 src/fpu/postproc/postprocess.sv     | 4 ++--
 src/fpu/postproc/shiftcorrection.sv | 8 +++++---
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/fpu/postproc/postprocess.sv b/src/fpu/postproc/postprocess.sv
index 2db03cb16..1ce993c33 100644
--- a/src/fpu/postproc/postprocess.sv
+++ b/src/fpu/postproc/postprocess.sv
@@ -157,11 +157,11 @@ module postprocess import cvw::*;  #(parameter cvw_t P) (
       end
       2'b00: begin // cvt
         ShiftAmt = {{P.LOGNORMSHIFTSZ-$clog2(P.CVTLEN+1){1'b0}}, CvtShiftAmt};
-        ShiftIn  =  {CvtShiftIn, {P.NORMSHIFTSZ-P.CVTLEN-P.NF-1{1'b0}}};
+        ShiftIn  =  {CvtShiftIn, {P.NORMSHIFTSZ-(P.CVTLEN+P.NF+1){1'b0}}};
       end
       2'b01: begin //divsqrt
         ShiftAmt = DivShiftAmt;
-        ShiftIn  = {{P.NF{1'b0}}, DivUm, {P.NORMSHIFTSZ-P.DIVb-1-P.NF{1'b0}}};
+        ShiftIn  = {{P.NF{1'b0}}, DivUm, {P.NORMSHIFTSZ-(P.DIVb+1+P.NF){1'b0}}};
       end
       default: begin 
         ShiftAmt = {P.LOGNORMSHIFTSZ{1'bx}}; 
diff --git a/src/fpu/postproc/shiftcorrection.sv b/src/fpu/postproc/shiftcorrection.sv
index ad811a747..0f366a4b4 100644
--- a/src/fpu/postproc/shiftcorrection.sv
+++ b/src/fpu/postproc/shiftcorrection.sv
@@ -69,12 +69,14 @@ module shiftcorrection import cvw::*;  #(parameter cvw_t P) (
   assign RightShift = FmaOp ? LZAPlus1 : LeftShiftQm;
 
   // one bit right shift for FMA or division
-  mux2 #(P.NORMSHIFTSZ) corrmux({Shifted[P.NORMSHIFTSZ-3:0], 2'b00}, {Shifted[P.NORMSHIFTSZ-2:1], 2'b00}, RightShift, CorrShifted);
+//  mux2 #(P.NORMSHIFTSZ) corrmux({Shifted[P.NORMSHIFTSZ-3:0], 2'b00}, {Shifted[P.NORMSHIFTSZ-2:1], 2'b00}, RightShift, CorrShifted);
   
   // if the result of the divider was calculated to be subnormal, then the result was correctly normalized, so select the top shifted bits
   always_comb
-    if (FmaOp | (DivOp & ~DivResSubnorm))  Mf = CorrShifted;
-    else                                   Mf = Shifted[P.NORMSHIFTSZ-1:0];
+    if (FmaOp | (DivOp & ~DivResSubnorm))  // one bit shift for FMA or division
+      if (RightShift)                      Mf = {Shifted[P.NORMSHIFTSZ-2:1], 2'b00};
+      else                                 Mf = {Shifted[P.NORMSHIFTSZ-3:0], 2'b00};
+    else                                   Mf =  Shifted[P.NORMSHIFTSZ-1:0];  // convert and subnormal division result
     
   // Determine sum's exponent
   //  main exponent issues: