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feat(big): add Div

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fallenoak 2023-02-01 23:27:32 -06:00
parent 24c6a5134c
commit 4d3651134c
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3 changed files with 133 additions and 0 deletions
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17
storm/big/Ops.cpp
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@ -34,6 +34,23 @@ int32_t Compare(const BigBuffer& a, const BigBuffer& b) {
return result;
}
void Div(BigBuffer& a, uint32_t* b, const BigBuffer& c, uint64_t d) {
// TODO STORM_ASSERT(d <= SMALL_BOUND);
auto index = c.Count();
a.SetCount(index);
uint64_t data = 0;
while (index > 0) {
InsertLowPart(data, c[--index]);
a[index] = data / d;
data %= d;
}
a.Trim();
*b = data;
}
uint32_t ExtractLowPart(uint64_t& value) {
auto low = static_cast<uint32_t>(value);
value >>= 32;

2
storm/big/Ops.hpp
View file

@ -11,6 +11,8 @@ void Add(BigBuffer& a, const BigBuffer& b, const BigBuffer& c);
int32_t Compare(const BigBuffer& a, const BigBuffer& b);
void Div(BigBuffer& a, uint32_t* b, const BigBuffer& c, uint64_t d);
uint32_t ExtractLowPart(uint64_t& value);
uint32_t ExtractLowPartSx(uint64_t& value);

114
test/Big.cpp
View file

@ -147,6 +147,120 @@ TEST_CASE("Compare", "[big]") {
}
}
TEST_CASE("Div", "[big]") {
SECTION("divides 2 by 1") {
BigData* a;
SBigNew(&a);
uint32_t b;
BigData* c;
SBigNew(&c);
SBigFromUnsigned(c, 2);
uint64_t d = 1;
Div(a->Primary(), &b, c->Primary(), d);
CHECK(a->Primary().Count() == 1);
CHECK(a->Primary()[0] == 2);
CHECK(b == 0);
SBigDel(a);
SBigDel(c);
}
SECTION("divides 5 by 2") {
BigData* a;
SBigNew(&a);
uint32_t b;
BigData* c;
SBigNew(&c);
SBigFromUnsigned(c, 5);
uint64_t d = 2;
Div(a->Primary(), &b, c->Primary(), d);
CHECK(a->Primary().Count() == 1);
CHECK(a->Primary()[0] == 2);
CHECK(b == 1);
SBigDel(a);
SBigDel(c);
}
SECTION("divides 7 by 4") {
BigData* a;
SBigNew(&a);
uint32_t b;
BigData* c;
SBigNew(&c);
SBigFromUnsigned(c, 7);
uint64_t d = 4;
Div(a->Primary(), &b, c->Primary(), d);
CHECK(a->Primary().Count() == 1);
CHECK(a->Primary()[0] == 1);
CHECK(b == 3);
SBigDel(a);
SBigDel(c);
}
SECTION("divides 0x9999444488885555 by 0x2222") {
BigData* a;
SBigNew(&a);
uint32_t b;
BigData* c;
SBigNew(&c);
uint64_t c_ = 0x9999444488885555;
SBigFromBinary(c, reinterpret_cast<uint8_t*>(&c_), sizeof(c_));
uint64_t d = 0x2222;
Div(a->Primary(), &b, c->Primary(), d);
CHECK(a->Primary().Count() == 2);
CHECK(a->Primary()[0] == 0x00040002);
CHECK(a->Primary()[1] == 0x48002);
CHECK(b == 0x1111);
SBigDel(a);
SBigDel(c);
}
SECTION("divides 0x9999444488885555 by 0xFFFFFFFF") {
BigData* a;
SBigNew(&a);
uint32_t b;
BigData* c;
SBigNew(&c);
uint64_t c_ = 0x9999444488885555;
SBigFromBinary(c, reinterpret_cast<uint8_t*>(&c_), sizeof(c_));
uint64_t d = 0xFFFFFFFF;
Div(a->Primary(), &b, c->Primary(), d);
CHECK(a->Primary().Count() == 1);
CHECK(a->Primary()[0] == 0x99994445);
CHECK(b == 0x2221999A);
SBigDel(a);
SBigDel(c);
}
}
TEST_CASE("ExtractLowPart", "[big]") {
SECTION("extracts low part of 0") {