fastnum 0.7.4

Fast decimal numbers library
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30

/// Performance notes:
///
/// For `x86_64`
///
/// ```asm
/// mov     rdx, rsi
/// mulx    rdx, rax, rdi
/// ret
/// ```
#[inline(always)]
pub const fn _widening_mul_64(a: u64, b: u64) -> (u64, u64) {
    let result = (a as u128) * (b as u128);
    (result as u64, (result >> 64) as u64)
}

#[inline(always)]
pub const fn _carrying_mul_64(multiplier: u64, multiplicand: u64, carry: u64) -> (u64, u64) {
    _carrying_mul_add_64(multiplier, multiplicand, carry, 0)
}

#[inline(always)]
pub const fn _carrying_mul_add_64(
    multiplier: u64,
    multiplicand: u64,
    addend: u64,
    carry: u64,
) -> (u64, u64) {
    let prod = carry as u128 + addend as u128 + (multiplier as u128) * (multiplicand as u128);
    (prod as u64, (prod >> u64::BITS) as u64)
}