GO Sub32用法及代码示例

GO语言"math/bits"包中"Sub32"函数的用法及代码示例。

用法:

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

Sub32 返回 x、y 和借位的差，diff = x - y - 借位。借位输入必须为 0 或 1；否则行为未定义。 borrowOut 输出保证为 0 或 1。

此函数的执行时间不依赖于输入。

例子：

package main

import (
	"fmt"
	"math/bits"
)

func main() {
	// First number is 33<<32 + 23
	n1 := []uint32{33, 23}
	// Second number is 21<<32 + 12
	n2 := []uint32{21, 12}
	// Sub them together without producing carry.
	d1, carry := bits.Sub32(n1[1], n2[1], 0)
	d0, _ := bits.Sub32(n1[0], n2[0], carry)
	nsum := []uint32{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)

	// First number is 3<<32 + 2147483647
	n1 = []uint32{3, 0x7fffffff}
	// Second number is 1<<32 + 2147483648
	n2 = []uint32{1, 0x80000000}
	// Sub them together producing carry.
	d1, carry = bits.Sub32(n1[1], n2[1], 0)
	d0, _ = bits.Sub32(n1[0], n2[0], carry)
	nsum = []uint32{d0, d1}
	fmt.Printf("%v - %v = %v (carry bit was %v)\n", n1, n2, nsum, carry)
}

输出：

[33 23] - [21 12] = [12 11] (carry bit was 0)
[3 2147483647] - [1 2147483648] = [1 4294967295] (carry bit was 1)

相关用法

注：本文由纯净天空筛选整理自golang.google.cn大神的英文原创作品 Sub32。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。