GO Sub64用法及代碼示例

GO語言"math/bits"包中"Sub64"函數的用法及代碼示例。

用法:

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

Sub64 返回 x、y 和借位的差：diff = x - y - 借位。借位輸入必須為 0 或 1；否則行為未定義。 borrowOut 輸出保證為 0 或 1。

此函數的執行時間不依賴於輸入。

例子：

package main

import (
    "fmt"
    "math/bits"
)

func main() {
    // First number is 33<<64 + 23
    n1 := []uint64{33, 23}
    // Second number is 21<<64 + 12
    n2 := []uint64{21, 12}
    // Sub them together without producing carry.
    d1, carry := bits.Sub64(n1[1], n2[1], 0)
    d0, _ := bits.Sub64(n1[0], n2[0], carry)
    nsum := []uint64{d0, d1}
    fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

    // First number is 3<<64 + 9223372036854775807
    n1 = []uint64{3, 0x7fffffffffffffff}
    // Second number is 1<<64 + 9223372036854775808
    n2 = []uint64{1, 0x8000000000000000}
    // Sub them together producing carry.
    d1, carry = bits.Sub64(n1[1], n2[1], 0)
    d0, _ = bits.Sub64(n1[0], n2[0], carry)
    nsum = []uint64{d0, d1}
    fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

輸出：

[33 23] - [21 12] = [12 11] (carry bit was 0)
[3 9223372036854775807] - [1 9223372036854775808] = [1 18446744073709551615] (carry bit was 1)

相關用法

注：本文由純淨天空篩選整理自golang.google.cn大神的英文原創作品 Sub64。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。