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Improved illegal NaN-box detection and formatted fsgninj

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This commit is contained in:
David Harris 2023-02-04 03:42:20 -08:00
parent ed02d5a077
commit e0915acad9
3 changed files with 28 additions and 26 deletions
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18
src/fpu/fsgninj.sv
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@ -29,11 +29,11 @@
`include "wally-config.vh"
module fsgninj (
input logic Xs, Ys, // X and Y sign bits
input logic [`FLEN-1:0] X, // X
input logic [`FMTBITS-1:0] Fmt, // format
input logic [1:0] OpCtrl, // operation control
output logic [`FLEN-1:0] SgnRes // result
input logic Xs, Ys, // X and Y sign bits
input logic [`FLEN-1:0] X, // X
input logic [`FMTBITS-1:0] Fmt, // format
input logic [1:0] OpCtrl, // operation control
output logic [`FLEN-1:0] SgnRes // result
);
logic ResSgn; // result sign
@ -54,13 +54,13 @@ module fsgninj (
assign SgnRes = {ResSgn, X[`FLEN-2:0]};
else if (`FPSIZES == 2)
assign SgnRes = {~Fmt|ResSgn, X[`FLEN-2:`LEN1], Fmt ? X[`LEN1-1] : ResSgn, X[`LEN1-2:0]};
else if (`FPSIZES == 3) begin
else if (`FPSIZES == 3) begin
logic [2:0] SgnBits;
always_comb
case (Fmt)
`FMT: SgnBits = {ResSgn, X[`LEN1-1], X[`LEN2-1]};
`FMT1: SgnBits = {1'b1, ResSgn, X[`LEN2-1]};
`FMT2: SgnBits = {2'b11, ResSgn};
`FMT: SgnBits = {ResSgn, X[`LEN1-1], X[`LEN2-1]};
`FMT1: SgnBits = {1'b1, ResSgn, X[`LEN2-1]};
`FMT2: SgnBits = {2'b11, ResSgn};
default: SgnBits = {3{1'bx}};
endcase
assign SgnRes = {SgnBits[2], X[`FLEN-2:`LEN1], SgnBits[1], X[`LEN1-2:`LEN2], SgnBits[0], X[`LEN2-2:0]};

11
src/fpu/unpack.sv
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@ -48,15 +48,14 @@ module unpack (
unpackinput unpackinputX (.In(X), .Fmt, .Sgn(Xs), .Exp(Xe), .Man(Xm), .En(XEn),
.NaN(XNaN), .SNaN(XSNaN), .ExpNonZero(XExpNonZero),
.Zero(XZero), .Inf(XInf), .ExpMax(XExpMax), .FracZero(XFracZero));
.Zero(XZero), .Inf(XInf), .ExpMax(XExpMax), .FracZero(XFracZero), .Subnorm(XSubnorm));
unpackinput unpackinputY (.In(Y), .Fmt, .Sgn(Ys), .Exp(Ye), .Man(Ym), .En(YEn),
.NaN(YNaN), .SNaN(YSNaN), .ExpNonZero(YExpNonZero),
.Zero(YZero), .Inf(YInf), .ExpMax(YExpMax), .FracZero(YFracZero));
.Zero(YZero), .Inf(YInf), .ExpMax(YExpMax), .FracZero(YFracZero), .Subnorm());
unpackinput unpackinputZ (.In(Z), .Fmt, .Sgn(Zs), .Exp(Ze), .Man(Zm), .En(ZEn),
.NaN(ZNaN), .SNaN(ZSNaN), .ExpNonZero(ZExpNonZero),
.Zero(ZZero), .Inf(ZInf), .ExpMax(ZExpMax), .FracZero(ZFracZero));
// is the input subnormal
assign XSubnorm = ~XExpNonZero & ~XFracZero;
endmodule
.Zero(ZZero), .Inf(ZInf), .ExpMax(ZExpMax), .FracZero(ZFracZero), .Subnorm());
endmodule

25
src/fpu/unpackinput.sv
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@ -31,16 +31,17 @@ module unpackinput (
input logic [`FLEN-1:0] In, // inputs from register file
input logic En, // enable the input
input logic [`FMTBITS-1:0] Fmt, // format signal 00 - single 01 - double 11 - quad 10 - half
output logic Sgn, // sign bits of XYZ
output logic [`NE-1:0] Exp, // exponents of XYZ (converted to largest supported precision)
output logic [`NF:0] Man, // mantissas of XYZ (converted to largest supported precision)
output logic NaN, // is XYZ a NaN
output logic SNaN, // is XYZ a signaling NaN
output logic Zero, // is XYZ zero
output logic Inf, // is XYZ infinity
output logic Sgn, // sign bits of the number
output logic [`NE-1:0] Exp, // exponent of the number (converted to largest supported precision)
output logic [`NF:0] Man, // mantissa of the number (converted to largest supported precision)
output logic NaN, // is the number a NaN
output logic SNaN, // is the number a signaling NaN
output logic Zero, // is the number zero
output logic Inf, // is the number infinity
output logic ExpNonZero, // is the exponent not zero
output logic FracZero, // is the fraction zero
output logic ExpMax // does In have the maximum exponent (NaN or Inf)
output logic ExpMax, // does In have the maximum exponent (NaN or Inf)
output logic Subnorm // is the number subnormal
);
logic [`NF-1:0] Frac; // Fraction of XYZ
@ -261,10 +262,12 @@ module unpackinput (
end
// Output logic
assign FracZero = ~|Frac; // is the fraction zero?
assign FracZero = ~|Frac & ~BadNaNBox; // is the fraction zero?
assign Man = {ExpNonZero, Frac}; // add the assumed one (or zero if Subnormal or zero) to create the significand
assign NaN = ((ExpMax & ~FracZero)|BadNaNBox)&En; // is the input a NaN?
assign SNaN = NaN&~Frac[`NF-1]&~BadNaNBox; // is the input a singnaling NaN?
assign Inf = ExpMax & FracZero &En; // is the input infinity?
assign Zero = ~ExpNonZero & FracZero; // is the input zero?
assign Inf = ExpMax & FracZero &En & ~BadNaNBox; // is the input infinity?
assign Zero = ~ExpNonZero & FracZero & ~BadNaNBox; // is the input zero?
assign Subnorm = ~ExpNonZero & ~FracZero & ~BadNaNBox; // is the input subnormal
endmodule