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big ints: mulWrap tests

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This commit is contained in:
Robin Voetter 2021-10-04 00:05:10 +02:00
parent b352564b36
commit a62ce87f1f
1 changed files with 78 additions and 1 deletions
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79
lib/std/math/big/int_test.zig
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@ -971,6 +971,84 @@ test "big.int mul large" {
try testing.expect(b.eq(c));
}
test "big.int mulWrap single-single unsigned" {
var a = try Managed.initSet(testing.allocator, 1234);
defer a.deinit();
var b = try Managed.initSet(testing.allocator, 5678);
defer b.deinit();
var c = try Managed.init(testing.allocator);
defer c.deinit();
try c.mulWrap(a.toConst(), b.toConst(), .unsigned, 17);
try testing.expect((try c.to(u17)) == 59836);
}
test "big.int mulWrap single-single signed" {
var a = try Managed.initSet(testing.allocator, 1234);
defer a.deinit();
var b = try Managed.initSet(testing.allocator, -5678);
defer b.deinit();
var c = try Managed.init(testing.allocator);
defer c.deinit();
try c.mulWrap(a.toConst(), b.toConst(), .signed, 17);
try testing.expect((try c.to(i17)) == -59836);
}
test "big.int mulWrap multi-multi unsigned" {
const op1 = 0x998888efefefefefefefef;
const op2 = 0x333000abababababababab;
var a = try Managed.initSet(testing.allocator, op1);
defer a.deinit();
var b = try Managed.initSet(testing.allocator, op2);
defer b.deinit();
var c = try Managed.init(testing.allocator);
defer c.deinit();
try c.mulWrap(a.toConst(), b.toConst(), .unsigned, 65);
try testing.expect((try c.to(u256)) == (op1 * op2) & ((1 << 65) - 1));
}
test "big.int mulWrap multi-multi signed" {
var a = try Managed.initSet(testing.allocator, maxInt(SignedDoubleLimb) - 1);
defer a.deinit();
var b = try Managed.initSet(testing.allocator, maxInt(SignedDoubleLimb));
defer b.deinit();
var c = try Managed.init(testing.allocator);
defer c.deinit();
try c.mulWrap(a.toConst(), b.toConst(), .signed, 128);
try testing.expect((try c.to(SignedDoubleLimb)) == minInt(SignedDoubleLimb) + 2);
}
test "big.int mulWrap large" {
var a = try Managed.initCapacity(testing.allocator, 50);
defer a.deinit();
var b = try Managed.initCapacity(testing.allocator, 100);
defer b.deinit();
var c = try Managed.initCapacity(testing.allocator, 100);
defer c.deinit();
// Generate a number that's large enough to cross the thresholds for the use
// of subquadratic algorithms
for (a.limbs) |*p| {
p.* = std.math.maxInt(Limb);
}
a.setMetadata(true, 50);
const testbits = @bitSizeOf(Limb) * 64 + 45;
try b.mulWrap(a.toConst(), a.toConst(), .signed, testbits);
try c.sqr(a.toConst());
try c.truncate(c.toConst(), .signed, testbits);
try testing.expect(b.eq(c));
}
test "big.int div single-single no rem" {
var a = try Managed.initSet(testing.allocator, 50);
defer a.deinit();
@ -1623,7 +1701,6 @@ test "big.int saturate multi unsigned zero" {
try testing.expect(a.eqZero());
}
test "big.int saturate multi unsigned" {
var a = try Managed.initSet(testing.allocator, maxInt(Limb) << @bitSizeOf(DoubleLimb));
defer a.deinit();