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Cleaning up divshiftcalc LOGNORMSHIFTSZ

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This commit is contained in:
David Harris 2022-09-20 02:35:01 -07:00
parent c797aee62c
commit 712f1d8d3a
4 changed files with 16 additions and 11 deletions
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4
pipelined/src/fpu/divshiftcalc.sv
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@ -5,7 +5,7 @@ module divshiftcalc(
input logic [`FMTBITS-1:0] Fmt,
input logic Sqrt,
input logic [`NE+1:0] DivQe,
output logic [$clog2(`NORMSHIFTSZ)-1:0] DivShiftAmt,
output logic [`LOGNORMSHIFTSZ-1:0] DivShiftAmt,
output logic [`NORMSHIFTSZ-1:0] DivShiftIn,
output logic DivResDenorm,
output logic [`NE+1:0] DivDenormShift
@ -36,7 +36,7 @@ module divshiftcalc(
assign NormShift = (`NE+2)'(`NF);
// if the shift amount is negitive then dont shift (keep sticky bit)
// need to multiply the early termination shift by LOGR*DIVCOPIES = left shift of log2(LOGR*DIVCOPIES)
assign DivShiftAmt = (DivResDenorm ? DivDenormShift[$clog2(`NORMSHIFTSZ)-1:0]&{$clog2(`NORMSHIFTSZ){~DivDenormShift[`NE+1]}} : NormShift[$clog2(`NORMSHIFTSZ)-1:0])+{{$clog2(`NORMSHIFTSZ)-`DURLEN-$clog2(`LOGR*`DIVCOPIES){1'b0}},
assign DivShiftAmt = (DivResDenorm ? DivDenormShift[`LOGNORMSHIFTSZ-1:0]&{`LOGNORMSHIFTSZ{~DivDenormShift[`NE+1]}} : NormShift[`LOGNORMSHIFTSZ-1:0])+{{`LOGNORMSHIFTSZ-`DURLEN-$clog2(`LOGR*`DIVCOPIES){1'b0}},
DivEarlyTermShift&{`DURLEN{~(DivDenormShift[`NE+1]|Sqrt)}}, {$clog2(`LOGR*`DIVCOPIES){1'b0}}};
assign DivShiftIn = {{`NF{1'b0}}, DivQm, {`NORMSHIFTSZ-`DIVb+1+(`RADIX/4)-`NF{1'b0}}};

11
pipelined/src/fpu/fdivsqrtpostproc.sv
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@ -37,7 +37,7 @@ module fdivsqrtpostproc(
input logic [`DIVb+1:0] FirstC,
input logic Firstqn,
input logic SqrtM,
output logic [`DIVb-(`RADIX/4):0] QmM,
output logic [`DIVb-(`RADIX/4):0] QmM, // *** why
output logic WZero,
output logic DivSM
);
@ -71,6 +71,11 @@ module fdivsqrtpostproc(
// division takes the result from the next cycle, which is shifted to the left one more time so the square root also needs to be shifted
always_comb
if(NegSticky) QmM = FirstUM[`DIVb:(`RADIX/4)] << SqrtM;
else QmM = FirstU[`DIVb:(`RADIX/4)] << SqrtM;
if (SqrtM) begin
if(NegSticky) QmM = FirstUM[`DIVb-(`RADIX/4):0] << 1;
else QmM = FirstU[`DIVb-(`RADIX/4):0] << 1;
end else begin // divide
if(NegSticky) QmM = FirstUM[`DIVb-(`RADIX/4):0];
else QmM = FirstU[`DIVb-(`RADIX/4):0];
end
endmodule

2
pipelined/src/fpu/normshift.sv
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@ -65,7 +65,7 @@
// - plus 1 to shift out the first 1
module normshift(
input logic [$clog2(`NORMSHIFTSZ)-1:0] ShiftAmt, // normalization shift count
input logic [`LOGNORMSHIFTSZ-1:0] ShiftAmt, // normalization shift count
input logic [`NORMSHIFTSZ-1:0] ShiftIn, // is the sum zero
output logic [`NORMSHIFTSZ-1:0] Shifted // is the sum zero
);

10
pipelined/src/fpu/postprocess.sv
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@ -83,7 +83,7 @@ module postprocess (
logic [`CORRSHIFTSZ-1:0] Mf; // corectly shifted fraction
logic [`NE+1:0] FullRe; // Re with bits to determine sign and overflow
logic UfPlus1; // do you add one (for determining underflow flag)
logic [$clog2(`NORMSHIFTSZ)-1:0] ShiftAmt; // normalization shift count
logic [`LOGNORMSHIFTSZ-1:0] ShiftAmt; // normalization shift count
logic [`NORMSHIFTSZ-1:0] ShiftIn; // is the sum zero
logic [`NORMSHIFTSZ-1:0] Shifted; // the shifted result
logic Plus1; // add one to the final result?
@ -98,7 +98,7 @@ module postprocess (
logic FmaPreResultDenorm; // is the result denormalized - calculated before LZA corection
logic [$clog2(3*`NF+7)-1:0] FmaShiftAmt; // normalization shift count
// division singals
logic [$clog2(`NORMSHIFTSZ)-1:0] DivShiftAmt;
logic [`LOGNORMSHIFTSZ-1:0] DivShiftAmt;
logic [`NORMSHIFTSZ-1:0] DivShiftIn;
logic [`NE+1:0] Qe;
logic DivByZero;
@ -156,11 +156,11 @@ module postprocess (
always_comb
case(PostProcSel)
2'b10: begin // fma
ShiftAmt = {{$clog2(`NORMSHIFTSZ)-$clog2(3*`NF+7){1'b0}}, FmaShiftAmt};
ShiftAmt = {{`LOGNORMSHIFTSZ-$clog2(3*`NF+7){1'b0}}, FmaShiftAmt};
ShiftIn = {FmaShiftIn, {`NORMSHIFTSZ-(3*`NF+8){1'b0}}};
end
2'b00: begin // cvt
ShiftAmt = {{$clog2(`NORMSHIFTSZ)-$clog2(`CVTLEN+1){1'b0}}, CvtShiftAmt};
ShiftAmt = {{`LOGNORMSHIFTSZ-$clog2(`CVTLEN+1){1'b0}}, CvtShiftAmt};
ShiftIn = {CvtShiftIn, {`NORMSHIFTSZ-`CVTLEN-`NF-1{1'b0}}};
end
2'b01: begin //div
@ -173,7 +173,7 @@ module postprocess (
end
end
default: begin
ShiftAmt = {$clog2(`NORMSHIFTSZ){1'bx}};
ShiftAmt = {`LOGNORMSHIFTSZ{1'bx}};
ShiftIn = {`NORMSHIFTSZ{1'bx}};
end
endcase