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Fixed spacing

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Harshini Srinath 2023-07-30 17:32:46 -07:00 committed by GitHub
parent d7b2d84124
commit bbbd5f6b2d
1 changed files with 25 additions and 30 deletions
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src/fpu/fma/fmaalign.sv
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@ -1,4 +1,3 @@
///////////////////////////////////////////
// fmaalign.sv
//
@ -28,18 +27,18 @@
////////////////////////////////////////////////////////////////////////////////////////////////
module fmaalign import cvw::*; #(parameter cvw_t P) (
input logic [P.NE-1:0] Xe, Ye, Ze, // biased exponents in B(NE.0) format
input logic [P.NF:0] Zm, // significand in U(0.NF) format]
input logic XZero, YZero, ZZero,// is the input zero
output logic [3*P.NF+3:0] Am, // addend aligned for addition in U(NF+5.2NF+1)
output logic ASticky, // Sticky bit calculated from the aliged addend
output logic KillProd // should the product be set to zero
input logic [P.NE-1:0] Xe, Ye, Ze, // biased exponents in B(NE.0) format
input logic [P.NF:0] Zm, // significand in U(0.NF) format]
input logic XZero, YZero, ZZero, // is the input zero
output logic [3*P.NF+3:0] Am, // addend aligned for addition in U(NF+5.2NF+1)
output logic ASticky, // Sticky bit calculated from the aliged addend
output logic KillProd // should the product be set to zero
);
logic [P.NE+1:0] ACnt; // how far to shift the addend to align with the product in Q(NE+2.0) format
logic [4*P.NF+3:0] ZmShifted; // output of the alignment shifter including sticky bits U(NF+5.3NF+1)
logic [4*P.NF+3:0] ZmPreshifted; // input to the alignment shifter U(NF+5.3NF+1)
logic KillZ; // should the addend be killed
logic [P.NE+1:0] ACnt; // how far to shift the addend to align with the product in Q(NE+2.0) format
logic [4*P.NF+3:0] ZmShifted; // output of the alignment shifter including sticky bits U(NF+5.3NF+1)
logic [4*P.NF+3:0] ZmPreshifted; // input to the alignment shifter U(NF+5.3NF+1)
logic KillZ; // should the addend be killed
///////////////////////////////////////////////////////////////////////////////
// Alignment shifter
@ -51,45 +50,41 @@ module fmaalign import cvw::*; #(parameter cvw_t P) (
// This could have been done using Pe, but ACnt is on the critical path so we replicate logic for speed
assign ACnt = {2'b0, Xe} + {2'b0, Ye} - {2'b0, (P.NE)'(P.BIAS)} + (P.NE+2)'(P.NF+2) - {2'b0, Ze};
// Defualt Addition with only inital left shift
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
// Default Addition with only inital left shift
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
assign ZmPreshifted = {Zm,(3*P.NF+3)'(0)};
assign KillProd = (ACnt[P.NE+1]&~ZZero)|XZero|YZero;
assign KillZ = $signed(ACnt)>$signed((P.NE+2)'(3)*(P.NE+2)'(P.NF)+(P.NE+2)'(3));
assign KillProd = (ACnt[P.NE+1]&~ZZero)|XZero|YZero;
assign KillZ = $signed(ACnt)>$signed((P.NE+2)'(3)*(P.NE+2)'(P.NF)+(P.NE+2)'(3));
always_comb begin
// If the product is too small to effect the sum, kill the product
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
if (KillProd) begin
ZmShifted = {(P.NF+2)'(0), Zm, (2*P.NF+1)'(0)};
ASticky = ~(XZero|YZero);
ASticky = ~(XZero|YZero);
// If the addend is too small to effect the addition
// - The addend has to shift two past the end of the product to be considered too small
// - The 2 extra bits are needed for rounding
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
end else if (KillZ) begin
ZmShifted = 0;
ASticky = ~ZZero;
ASticky = ~ZZero;
// If the Addend is shifted right
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
// | 53'b0 | 106'b(product) | 1'b0 |
// | addnend |
end else begin
ZmShifted = ZmPreshifted >> ACnt;
ASticky = |(ZmShifted[P.NF-1:0]);
ASticky = |(ZmShifted[P.NF-1:0]);
end
end
assign Am = ZmShifted[4*P.NF+3:P.NF];
endmodule