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Square root negative exponent handling

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This commit is contained in:
cturek 2022-07-22 16:45:19 +00:00
parent 12c92a05ff
commit 338f44dfc8
5 changed files with 41 additions and 23 deletions
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BIN
pipelined/srt/sqrttestgen
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33
pipelined/srt/sqrttestgen.c
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@ -1,6 +1,6 @@
/* sqrttestgen.c */
/* Written 19 October 2021 David_Harris@hmc.edu
/* Written 7/22/2022 by Cedar Turek
This program creates test vectors for mantissa component
of an IEEE floating point square root.
@ -15,6 +15,7 @@
/* Constants */
#define ENTRIES 17
#define BIGENT 1000
#define RANDOM_VECS 500
/* Prototypes */
@ -34,6 +35,9 @@ void main(void)
1.75, 1.875, 1.99999,
1.1, 1.5, 1.01, 1.001, 1.0001,
2/1.1, 2/1.5, 2/1.25, 2/1.125};
double bigtest[BIGENT];
double exps[ENTRIES] = {0, 0, 2, 3, 4, 5, 6, 7, 8, 1, 10,
11, 12, 13, 14, 15, 16};
int i;
@ -44,13 +48,14 @@ void main(void)
exit(1);
}
for (i=0; i<ENTRIES; i++) {
aFrac = mans[i];
aExp = exps[i] + bias;
rFrac = sqrt(aFrac * pow(2, exps[i]));
rExp = (int) (log(rFrac)/log(2) + bias);
output(fptr, aExp, aFrac, rExp, rFrac);
}
// Small Test
// for (i=0; i<ENTRIES; i++) {
// aFrac = mans[i];
// aExp = exps[i] + bias;
// rFrac = sqrt(aFrac * pow(2, exps[i]));
// rExp = (int) (log(rFrac)/log(2) + bias);
// output(fptr, aExp, aFrac, rExp, rFrac);
// }
// WS
// Test 1: sqrt(1) = 1 0000 0000 0000 00
@ -67,6 +72,16 @@ void main(void)
// output(fptr, a, r);
// }
// Big Test
for (i=0; i<BIGENT; i++) {
bigtest[i] = random_input();
aFrac = bigtest[i];
aExp = (i - BIGENT/2) + bias;
rFrac = sqrt(aFrac * pow(2, (i - BIGENT/2)));
rExp = (int) (log(rFrac)/log(2) + bias);
output(fptr, aExp, aFrac, rExp, rFrac);
}
fclose(fptr);
}
@ -105,6 +120,6 @@ void printhex(FILE *fptr, double m)
double random_input(void)
{
return 1.0 + rand()/32767.0;
return 1.0 + ((rand() % 32768)/32767.0);
}

1
pipelined/srt/srt-waves.do
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@ -3,4 +3,5 @@ add wave -noupdate /testbench/srt/*
add wave -noupdate /testbench/srt/sotfc2/*
add wave -noupdate /testbench/srt/preproc/*
add wave -noupdate /testbench/srt/postproc/*
add wave -noupdate /testbench/srt/expcalc/*
add wave -noupdate /testbench/srt/divcounter/*

22
pipelined/srt/srt.sv
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@ -389,11 +389,11 @@ module expcalc(
input logic Sqrt,
output logic [`NE-1:0] calcExp
);
logic [`NE-1:0] SExp, DExp, SXExp;
assign SXExp = XExp - (`NE)'(`BIAS);
assign SExp = {1'b0, SXExp[`NE-1:1]} + (`NE)'(`BIAS);
assign DExp = XExp - YExp + (`NE)'(`BIAS);
assign calcExp = Sqrt ? SExp : DExp;
logic [`NE+1:0] SExp, DExp, SXExp;
assign SXExp = {2'b00, XExp} - (`NE+2)'(`BIAS);
assign SExp = (SXExp >> 1) + (`NE+2)'(`BIAS);
assign DExp = {2'b00, XExp} - {2'b00, YExp} + (`NE+2)'(`BIAS);
assign calcExp = Sqrt ? SExp[`NE-1:0] : DExp[`NE-1:0];
endmodule
@ -462,11 +462,13 @@ module srtpostproc(
end
assign floatRes = S[`DIVLEN] ? S[`DIVLEN:1] : S[`DIVLEN-1:0];
assign intRes = intS[`DIVLEN] ? intS[`DIVLEN:1] : intS[`DIVLEN-1:0];
assign shiftRem = (intRem >>> (`DIVLEN - dur + 2));
always_comb
if (Int) Result = intRes >> (`DIVLEN - dur);
else if (Mod) Result = shiftRem[`DIVLEN-1:0];
else Result = floatRes;
assign shiftRem = (intRem >> (zeroCntD));
always_comb begin
if (Int) begin
if (Mod) Result = shiftRem[`DIVLEN-1:0];
else Result = intRes >> (`DIVLEN - dur);
end else Result = floatRes;
end
assign calcSign = XSign ^ YSign;
endmodule

8
pipelined/srt/testbench.sv
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@ -53,7 +53,7 @@ module testbench;
// Test parameters
parameter MEM_SIZE = 40000;
parameter MEM_WIDTH = 64+64+64+64;
parameter MEM_WIDTH = 64+64+64;
// Test sizes
`define memr 63:0
@ -70,9 +70,9 @@ module testbench;
integer testnum, errors;
// Equip Int, Sqrt, or IntMod test
assign Int = 1'b1;
assign Int = 1'b0;
assign Mod = 1'b0;
assign Sqrt = 1'b0;
assign Sqrt = 1'b1;
// Divider
srt srt(.clk, .Start(req),
@ -101,7 +101,7 @@ module testbench;
begin
testnum = 0;
errors = 0;
$readmemh ("inttestvectors", Tests);
$readmemh ("sqrttestvectors", Tests);
Vec = Tests[testnum];
a = Vec[`mema];
{asign, aExp, afrac} = a;