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Fix $urandom_range maximum value (#2723)

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Nandu Raj 2020-12-22 18:22:38 +05:30 committed by GitHub
parent 4096dee598
commit 1124829500
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3 changed files with 10 additions and 6 deletions
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1
docs/CONTRIBUTORS
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@ -49,6 +49,7 @@ Marshal Qiao
Matthew Ballance Matthew Ballance
Michael Killough Michael Killough
Mike Popoloski Mike Popoloski
Nandu Raj
Nathan Kohagen Nathan Kohagen
Nathan Myers Nathan Myers
Patrick Stewart Patrick Stewart

4
include/verilated.h
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@ -661,9 +661,9 @@ inline IData VL_URANDOM_RANGE_I(IData hi, IData lo) {
vluint64_t rnd = vl_rand64(); vluint64_t rnd = vl_rand64();
if (VL_LIKELY(hi > lo)) { if (VL_LIKELY(hi > lo)) {
// Modulus isn't very fast but it's common that hi-low is power-of-two // Modulus isn't very fast but it's common that hi-low is power-of-two
return (rnd % (hi - lo)) + lo; return (rnd % (hi - lo + 1)) + lo;
} else { } else {
return (rnd % (lo - hi)) + hi; return (rnd % (lo - hi + 1)) + hi;
} }
} }

11
test_regress/t/t_urandom.v
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@ -34,14 +34,17 @@ module t(/*AUTOARG*/);
if (v1 == v2 && v1 == v3) $stop; // Possible, but 2^-64 if (v1 == v2 && v1 == v3) $stop; // Possible, but 2^-64
// Range // Range
v2 = $urandom_range(v1, v1);
if (v1 != v2) $stop;
for (int test = 0; test < 20; ++test) begin for (int test = 0; test < 20; ++test) begin
v1 = 2; v1 = 2;
v1 = $urandom_range(0, v1); v1 = $urandom_range(0, v1);
if (v1 != 0 && v1 != 1) $stop;
v1 = $urandom_range(2, 0);
if (v1 != 0 && v1 != 1) $stop;
v1 = $urandom_range(3);
if (v1 != 0 && v1 != 1 && v1 != 2) $stop; if (v1 != 0 && v1 != 1 && v1 != 2) $stop;
v1 = $urandom_range(2, 0);
if (v1 != 0 && v1 != 1 && v1 !=2) $stop;
v1 = $urandom_range(3);
if (v1 != 0 && v1 != 1 && v1 != 2 && v1 != 3) $stop;
end end
// Seed stability // Seed stability