bitXor
r = a ^ b under 2s complement semantics. r may alias with a or b.
Asserts that r has enough limbs to store the result. If a and b share the same signedness, the
upper bound is @max(a.limbs.len, b.limbs.len). Otherwise, if either a or b is negative
but not both, the upper bound is @max(a.limbs.len, b.limbs.len) + 1.
Function parameters
Parameters
Used to indicate either limit of a 2s-complement integer.
Types
- TwosCompIntLimit
- Used to indicate either limit of a 2s-complement integer.
- Mutable
- A arbitrary-precision big integer, with a fixed set of mutable limbs.
- Const
- A arbitrary-precision big integer, with a fixed set of immutable limbs.
- Managed
- An arbitrary-precision big integer along with an allocator which manages the memory.
Returns the number of limbs needed to store `scalar`, which must be a
Functions
- calcLimbLen
- Returns the number of limbs needed to store `scalar`, which must be a
- calcSetStringLimbCount
- Assumes `string_len` doesn't account for minus signs if the number is negative.
- calcNonZeroTwosCompLimbCount
- Compute the number of limbs required to store a 2s-complement number of `bit_count` bits.
- calcTwosCompLimbCount
- Compute the number of limbs required to store a 2s-complement number of `bit_count` bits.
- addMulLimbWithCarry
- a + b * c + *carry, sets carry to the overflow bits
- llcmp
- Returns -1, 0, 1 if |a| < |b|, |a| == |b| or |a| > |b| respectively for limbs.
Source
Implementation
pub fn bitXor(r: *Mutable, a: Const, b: Const) void {
// Trivial cases, because llsignedxor does not support negative zero.
if (a.eqlZero()) {
r.copy(b);
return;
} else if (b.eqlZero()) {
r.copy(a);
return;
}
if (a.limbs.len > b.limbs.len) {
r.positive = llsignedxor(r.limbs, a.limbs, a.positive, b.limbs, b.positive);
r.normalize(a.limbs.len + @intFromBool(a.positive != b.positive));
} else {
r.positive = llsignedxor(r.limbs, b.limbs, b.positive, a.limbs, a.positive);
r.normalize(b.limbs.len + @intFromBool(a.positive != b.positive));
}
}