Github_Repos/cvw
1
0
Fork 1
mirror of https://github.com/openhwgroup/cvw synced 2025-01-24 05:24:49 +00:00
Code Issues Packages Projects Releases Wiki Activity

fdivsqrt parameter cleanup

Browse Source
This commit is contained in:
David Harris 2023-11-10 09:11:15 -08:00
parent 4c106215f4
commit 953c53d065
5 changed files with 18 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
config/shared/config-shared.vh
View File

@ -94,15 +94,14 @@ localparam FMT2 = ((F_SUPPORTED & (LEN1 != S_LEN)) ? 2'd0 : 2'd2);
localparam BIAS2 = ((F_SUPPORTED & (LEN1 != S_LEN)) ? S_BIAS : H_BIAS);
// division constants
localparam DIVN = ((NF+2<XLEN) & IDIV_ON_FPU) ? XLEN : NF+2; // standard length of input
localparam LOGR = $clog2(RADIX); // r = log(R)
localparam RK = LOGR*DIVCOPIES; // r*k used for intdiv preproc
localparam LOGRK = $clog2(RK); // log2(r*k)
localparam FPDUR = (DIVN+1)/RK + 1 + (RADIX/4);
localparam DIVN = ((NF+2<XLEN) & IDIV_ON_FPU) ? XLEN : NF+2; // standard length of input: max(XLEN, NF+2)
localparam LOGR = $clog2(RADIX); // r = log(R)
localparam RK = LOGR*DIVCOPIES; // r*k bits per cycle generated
localparam LOGRK = $clog2(RK); // log2(r*k)
localparam FPDUR = (DIVN+1)/RK + 1 + (RADIX/4); //
localparam DURLEN = $clog2(FPDUR+1);
localparam DIVb = FPDUR*RK - 1; // canonical fdiv size (b)
localparam DIVBLEN = $clog2(DIVb+1)-1;
localparam DIVa = DIVb+1-XLEN; // used for idiv on fpu: Shift residual right by b - (XLEN-1) to put remainder in lsbs of integer result
localparam DIVBLEN = $clog2(DIVb+2)-1;
// largest length in IEU/FPU
localparam CVTLEN = ((NF<XLEN) ? (XLEN) : (NF)); // max(XLEN, NF)

3
config/shared/parameter-defs.vh
View File

@ -184,6 +184,5 @@ localparam cvw_t P = '{
FPDUR : FPDUR,
DURLEN : DURLEN,
DIVb : DIVb,
DIVBLEN : DIVBLEN,
DIVa : DIVa
DIVBLEN : DIVBLEN
};

1
src/cvw.sv
View File

@ -277,7 +277,6 @@ typedef struct packed {
int DURLEN ;
int DIVb ;
int DIVBLEN ;
int DIVa ;
} cvw_t;

3
src/fpu/fdivsqrt/fdivsqrtpostproc.sv
View File

@ -110,7 +110,8 @@ module fdivsqrtpostproc import cvw::*; #(parameter cvw_t P) (
mux2 #(P.DIVb+4) quotresmux(UnsignedQuotM, -UnsignedQuotM, NegQuotM, NormQuotM);
// Select quotient or remainder and do normalization shift
mux2 #(P.DIVBLEN+1) normshiftmux(((P.DIVBLEN+1)'(P.DIVb) - (nM * (P.DIVBLEN+1)'(P.LOGR))), (mM + (P.DIVBLEN+1)'(P.DIVa)), RemOpM, NormShiftM);
localparam DIVa = (P.DIVb+1-P.XLEN); // used for idiv on fpu: Shift residual right by b - (XLEN-1) to put remainder in lsbs of integer result
mux2 #(P.DIVBLEN+1) normshiftmux(((P.DIVBLEN+1)'(P.DIVb) - (nM * (P.DIVBLEN+1)'(P.LOGR))), (mM + (P.DIVBLEN+1)'(DIVa)), RemOpM, NormShiftM);
mux2 #(P.DIVb+4) presresultmux(NormQuotM, NormRemM, RemOpM, PreResultM);
assign PreIntResultM = $signed(PreResultM >>> NormShiftM);

18
src/fpu/fdivsqrt/fdivsqrtpreproc.sv
View File

@ -48,7 +48,7 @@ module fdivsqrtpreproc import cvw::*; #(parameter cvw_t P) (
output logic [P.XLEN-1:0] AM
);
logic [P.DIVb-1:0] Xfract, Dfract;
logic [P.DIVb:0] Xfract, Dfract;
logic [P.DIVb:0] PreSqrtX;
logic [P.DIVb+3:0] DivX, DivXShifted, SqrtX, PreShiftX; // Variations of dividend, to be muxed
logic [P.NE+1:0] QeE; // Quotient Exponent (FP only)
@ -103,12 +103,12 @@ module fdivsqrtpreproc import cvw::*; #(parameter cvw_t P) (
//////////////////////////////////////////////////////
// count leading zeros for Subnorm FP and to normalize integer inputs
lzc #(P.DIVb) lzcX (IFX[P.DIVb:1], ell);
lzc #(P.DIVb) lzcY (IFD[P.DIVb:1], mE);
lzc #(P.DIVb+1) lzcX (IFX, ell);
lzc #(P.DIVb+1) lzcY (IFD, mE);
// Normalization shift: shift off leading one
assign Xfract = (IFX[P.DIVb:1] << ell) << 1;
assign Dfract = (IFD[P.DIVb:1] << mE) << 1;
assign Xfract = (IFX << ell);
assign Dfract = (IFD << mE);
//////////////////////////////////////////////////////
// Integer Right Shift to digit boundary
@ -158,10 +158,10 @@ module fdivsqrtpreproc import cvw::*; #(parameter cvw_t P) (
// it comes out in the wash and gives the right answer. Investigate later if possible.
//////////////////////////////////////////////////////
assign DivX = {3'b000, ~NumerZeroE, Xfract};
assign DivX = {3'b000, Xfract};
// Sqrt is initialized on step one as R(X-1), so depends on Radix
mux2 #(P.DIVb+1) sqrtxmux({~XZeroE, Xfract}, {1'b0, ~XZeroE, Xfract[P.DIVb-1:1]}, (Xe[0] ^ ell[0]), PreSqrtX);
mux2 #(P.DIVb+1) sqrtxmux(Xfract, {1'b0, Xfract[P.DIVb:1]}, (Xe[0] ^ ell[0]), PreSqrtX);
if (P.RADIX == 2) assign SqrtX = {3'b111, PreSqrtX};
else assign SqrtX = {2'b11, PreSqrtX, 1'b0};
mux2 #(P.DIVb+4) prexmux(DivX, SqrtX, SqrtE, PreShiftX);
@ -176,8 +176,8 @@ module fdivsqrtpreproc import cvw::*; #(parameter cvw_t P) (
assign X = PreShiftX;
end
// Divisior register
flopen #(P.DIVb+4) dreg(clk, IFDivStartE, {4'b0001, Dfract}, D);
// Divisior register
flopen #(P.DIVb+4) dreg(clk, IFDivStartE, {3'b000, Dfract}, D);
// Floating-point exponent
fdivsqrtexpcalc #(P) expcalc(.Fmt(FmtE), .Xe, .Ye, .Sqrt(SqrtE), .XZero(XZeroE), .ell, .m(mE), .Qe(QeE));