subWrap
r = a - b with 2s-complement wrapping semantics. Returns whether any overflow occurred.
r, a and b may be aliases
Asserts the result fits in r. An upper bound on the number of limbs needed by
r is calcTwosCompLimbCount(bit_count).
Function parameters
Parameters
- r:*Mutable
- bit_count:usize
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 subWrap(r: *Mutable, a: Const, b: Const, signedness: Signedness, bit_count: usize) bool {
return r.addWrap(a, b.negate(), signedness, bit_count);
}