Merge branch 'main' of github.com:davidharrishmc/riscv-wally into main

pipelined/regression/wave-fpu.do

@@ -23,5 +23,6 @@ add wave -group {Divide} -noupdate /testbenchfp/srtradix4/qsel4/*
 add wave -group {Divide} -noupdate /testbenchfp/srtradix4/otfc4/*
 add wave -group {Divide} -noupdate /testbenchfp/srtradix4/preproc/*
 add wave -group {Divide} -noupdate /testbenchfp/srtradix4/divcounter/*
+add wave -group {Divide} -noupdate /testbenchfp/srtradix4/expcalc/*
 add wave -group {Testbench} -noupdate /testbenchfp/*
 add wave -group {Testbench} -noupdate /testbenchfp/readvectors/*

pipelined/src/fpu/divshiftcalc.sv

@@ -0,0 +1,15 @@
+`include "wally-config.vh"
+
+module divshiftcalc(
+    input logic  [`DIVLEN+2:0] Quot,
+    input logic  [`NE:0] DivCalcExpM,
+    output logic [$clog2(`NORMSHIFTSZ)-1:0] DivShiftAmt,
+    output logic [`NE:0] CorrDivExp
+);
+    
+    assign DivShiftAmt = {{$clog2(`NORMSHIFTSZ)-1{1'b0}}, ~Quot[`DIVLEN+2]};
+    // the quotent is in the range [.5,2)
+    // if the quotent < 1 and not denormal then subtract 1 to account for the normalization shift
+    assign CorrDivExp = DivCalcExpM - {(`NE)'(0), ~Quot[`DIVLEN+2]};
+
+endmodule

pipelined/src/fpu/postprocess.sv

@@ -94,6 +94,7 @@ module postprocess(
     logic                   IntToFp;       // is the opperation an int->fp conversion?
     logic                   ToInt;      // is the opperation an fp->int conversion?
     logic [`NE+1:0] RoundExp;
+    logic [`NE:0] CorrDivExp;
     logic [1:0] NegResMSBS;
     logic CvtOp;
     logic FmaOp;
@@ -138,7 +139,7 @@ module postprocess(
                               .XZeroM, .IntToFp, .OutFmt, .CvtResUf, .CvtShiftIn);
     fmashiftcalc fmashiftcalc(.SumM, .ZExpM, .ProdExpM, .FmaNormCntM, .FmtM, .KillProdM, .ConvNormSumExp,
                           .ZDenormM, .SumZero, .PreResultDenorm, .FmaShiftAmt, .FmaShiftIn);
-    divshiftcalc divshiftcalc(.Quot, .DivShiftAmt);
+    divshiftcalc divshiftcalc(.Quot, .DivCalcExpM, .CorrDivExp, .DivShiftAmt);
 
     always_comb
         case(PostProcSelM)
@@ -175,7 +176,7 @@ module postprocess(
     // round to infinity
     // round to nearest max magnitude
 
-    round round(.OutFmt, .FrmM, .Sticky, .AddendStickyM, .ZZeroM, .Plus1, .PostProcSelM, .CvtCalcExpM, .DivCalcExpM,
+    round round(.OutFmt, .FrmM, .Sticky, .AddendStickyM, .ZZeroM, .Plus1, .PostProcSelM, .CvtCalcExpM, .CorrDivExp,
                 .InvZM, .RoundSgn, .SumExp, .FmaOp, .CvtOp, .CvtResDenormUfM, .CorrShifted, .ToInt,  .CvtResUf,
                 .DivOp, .UfPlus1, .FullResExp, .ResFrac, .ResExp, .Round, .RoundAdd, .UfLSBRes, .RoundExp);
 

pipelined/src/fpu/round.sv

@@ -24,7 +24,7 @@ module round(
     input logic  [`NE+1:0]      SumExp,         // exponent of the normalized sum
     input logic                 RoundSgn,      // the result's sign
     input logic [`NE:0]           CvtCalcExpM,    // the calculated expoent
-    input logic [`NE:0]           DivCalcExpM,    // the calculated expoent
+    input logic [`NE:0]           CorrDivExp,    // the calculated expoent
     output logic                UfPlus1,  // do you add or subtract on from the result
     output logic [`NE+1:0]      FullResExp,      // ResExp with bits to determine sign and overflow
     output logic [`NF-1:0]      ResFrac,         // Result fraction
@@ -305,7 +305,7 @@ module round(
         case(PostProcSelM)
             2'b10: RoundExp = SumExp; // fma
             2'b00: RoundExp = {CvtCalcExpM[`NE], CvtCalcExpM}&{`NE+2{~CvtResDenormUfM|CvtResUf}}; // cvt
-            2'b01: RoundExp = {DivCalcExpM[`NE], DivCalcExpM[`NE:0]}; // divide
+            2'b01: RoundExp = {CorrDivExp[`NE], CorrDivExp[`NE:0]}; // divide
             default: RoundExp = 0; 
         endcase
 

synthDC/Makefile

@@ -15,6 +15,7 @@ export MAXCORES ?= 4
 # MAXOPT turns on flattening, boundary optimization, and retiming
 # The output netlist is hard to interpret, but significantly better PPA
 export MAXOPT ?= 0
+export DRIVE ?= FLOP
 
 time := $(shell date +%F-%H-%M)
 hash := $(shell git rev-parse --short HEAD)