https://github.com/smasher164/extprec

A portable implementation of extended precision integer arithmetic in Go.
https://github.com/smasher164/extprec

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A portable implementation of extended precision integer arithmetic in Go.

• Host: GitHub
• URL: https://github.com/smasher164/extprec
• Owner: smasher164
• License: mit
• Created: 2018-07-09T08:39:47.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-07-11T17:16:08.000Z (over 6 years ago)
• Last Synced: 2024-06-20T06:32:08.035Z (7 months ago)
• Language: Go
• Size: 30.3 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
This package provides a portable implementation of extended precision integer arithmetic operations in Go. Specifically, it implements the functions outlined for the math/bits package in [#24813](https://golang.org/issue/24813) as follows:

```

// Add with carry

// The carry inputs are assumed to be 0 or 1; otherwise behavior undefined.

// The carryOut outputs are guaranteed to be 0 or 1.

func Add(x, y, carry uint) (sum, carryOut uint)

func Add32(x, y, carry uint32) (sum, carryOut uint32)

func Add64(x, y, carry uint64) (sum, carryOut uint64)

// Subtract with borrow

// The borrow inputs are assumed to be 0 or 1; otherwise behavior undefined.

// The borrowOut outputs are guaranteed to be 0 or 1.

func Sub(x, y, borrow uint) (difference, borrowOut uint)

func Sub32(x, y, borrow uint32) (difference, borrowOut uint32)

func Sub64(x, y, borrow uint64) (difference, borrowOut uint64)

// Full-width multiply: 32x32->64, 64x64->128

func Mul(x, y uint) (hi, lo uint)

func Mul32(x, y uint32) (hi, lo uint32)

func Mul64(x, y uint64) (hi, lo uint64)

// Full-width divide: 64/32 -> 32,32, 128/64 -> 64,64

// Behavior undefined if hi >= x (because quotient will not fit).

func Div(hi, lo, x uint) (quo, rem uint)

func Div32(hi, lo, x uint32) (quo, rem uint32)

func Div64(hi, lo, x uint64) (quo, rem uint64)

```