51单片机pow怎么用
时间: 2024-09-23 17:02:21 浏览: 30
在51单片机中,并没有内置函数叫做`pow`,这是计算机科学中的数学运算库中的一个函数,用于计算一个数的幂。51系列单片机通常使用的汇编语言或C语言编写的程序中,若需要进行复杂数学运算,比如求幂,一般会通过循环或者查表的方式来模拟。
如果你是指使用C语言开发在51单片机上运行的应用,可以借助第三方库,如μC/OS-II或Keil C51集成环境提供的math.h头文件里的fabs()、sqrt()等函数,然后自己编写一个简单的算法来近似计算幂。例如:
```c
// 自己实现的简单幂运算
float myPow(float base, float exponent) {
float result = 1;
while (exponent > 0) {
if (exponent % 2 == 1) {
result *= base;
}
base *= base;
exponent /= 2;
}
return result;
}
```
然而,由于51单片机资源有限,这种方法效率并不高,对于精度要求高的场合,外部的数学运算芯片或者使用支持浮点运算的更高级别的MCU会更适合。
相关问题
51单片机c语言爱心代码
```
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<style>
* {
padding: 0;
margin: 0;
}
html,
body {
height: 100%;
padding: 0;
margin: 0;
background: #000;
}
canvas {
position: absolute;
width: 100%;
height: 100%;
}
.aa {
position: fixed;
left: 50%;
bottom: 10px;
color: #ccc;
}
</style>
<body>
<canvas id="pinkboard"></canvas>
<script>
/*
* Settings
*/
var settings = {
particles: {
length: 500, // maximum amount of particles
duration: 2, // particle duration in sec
velocity: 100, // particle velocity in pixels/sec
effect: -0.75, // play with this for a nice effect
size: 30 // particle size in pixels
}
};
/*
* RequestAnimationFrame polyfill by Erik M?ller
*/
(function () {
var b = 0;
var c = ["ms", "moz", "webkit", "o"];
for (var a = 0; a < c.length && !window.requestAnimationFrame; ++a) {
window.requestAnimationFrame = window[c[a] + "RequestAnimationFrame"];
window.cancelAnimationFrame =
window[c[a] + "CancelAnimationFrame"] ||
window[c[a] + "CancelRequestAnimationFrame"];
}
if (!window.requestAnimationFrame) {
window.requestAnimationFrame = function (h, e) {
var d = new Date().getTime();
var f = Math.max(0, 16 - (d - b));
var g = window.setTimeout(function () {
h(d + f);
}, f);
b = d + f;
return g;
};
}
if (!window.cancelAnimationFrame) {
window.cancelAnimationFrame = function (d) {
clearTimeout(d);
};
}
})();
/*
* Point class
*/
var Point = (function () {
function Point(x, y) {
this.x = typeof x !== "undefined" ? x : 0;
this.y = typeof y !== "undefined" ? y : 0;
}
Point.prototype.clone = function () {
return new Point(this.x, this.y);
};
Point.prototype.length = function (length) {
if (typeof length == "undefined")
return Math.sqrt(this.x * this.x + this.y * this.y);
this.normalize();
this.x *= length;
this.y *= length;
return this;
};
Point.prototype.normalize = function () {
var length = this.length();
this.x /= length;
this.y /= length;
return this;
};
return Point;
})();
/*
* Particle class
*/
var Particle = (function () {
function Particle() {
this.position = new Point();
this.velocity = new Point();
this.acceleration = new Point();
this.age = 0;
}
Particle.prototype.initialize = function (x, y, dx, dy) {
this.position.x = x;
this.position.y = y;
this.velocity.x = dx;
this.velocity.y = dy;
this.acceleration.x = dx * settings.particles.effect;
this.acceleration.y = dy * settings.particles.effect;
this.age = 0;
};
Particle.prototype.update = function (deltaTime) {
this.position.x += this.velocity.x * deltaTime;
this.position.y += this.velocity.y * deltaTime;
this.velocity.x += this.acceleration.x * deltaTime;
this.velocity.y += this.acceleration.y * deltaTime;
this.age += deltaTime;
};
Particle.prototype.draw = function (context, image) {
function ease(t) {
return --t * t * t + 1;
}
var size = image.width * ease(this.age / settings.particles.duration);
context.globalAlpha = 1 - this.age / settings.particles.duration;
context.drawImage(
image,
this.position.x - size / 2,
this.position.y - size / 2,
size,
size
);
};
return Particle;
})();
/*
* ParticlePool class
*/
var ParticlePool = (function () {
var particles,
firstActive = 0,
firstFree = 0,
duration = settings.particles.duration;
function ParticlePool(length) {
// create and populate particle pool
particles = new Array(length);
for (var i = 0; i < particles.length; i++)
particles[i] = new Particle();
}
ParticlePool.prototype.add = function (x, y, dx, dy) {
particles[firstFree].initialize(x, y, dx, dy);
// handle circular queue
firstFree++;
if (firstFree == particles.length) firstFree = 0;
if (firstActive == firstFree) firstActive++;
if (firstActive == particles.length) firstActive = 0;
};
ParticlePool.prototype.update = function (deltaTime) {
var i;
// update active particles
if (firstActive < firstFree) {
for (i = firstActive; i < firstFree; i++)
particles[i].update(deltaTime);
}
if (firstFree < firstActive) {
for (i = firstActive; i < particles.length; i++)
particles[i].update(deltaTime);
for (i = 0; i < firstFree; i++) particles[i].update(deltaTime);
}
// remove inactive particles
while (
particles[firstActive].age >= duration &&
firstActive != firstFree
) {
firstActive++;
if (firstActive == particles.length) firstActive = 0;
}
};
ParticlePool.prototype.draw = function (context, image) {
// draw active particles
if (firstActive < firstFree) {
for (i = firstActive; i < firstFree; i++)
particles[i].draw(context, image);
}
if (firstFree < firstActive) {
for (i = firstActive; i < particles.length; i++)
particles[i].draw(context, image);
for (i = 0; i < firstFree; i++) particles[i].draw(context, image);
}
};
return ParticlePool;
})();
/*
* Putting it all together
*/
(function (canvas) {
var context = canvas.getContext("2d"),
particles = new ParticlePool(settings.particles.length),
particleRate =
settings.particles.length / settings.particles.duration, // particles/sec
time;
// get point on heart with -PI <= t <= PI
function pointOnHeart(t) {
return new Point(
160 * Math.pow(Math.sin(t), 3),
130 * Math.cos(t) -
50 * Math.cos(2 * t) -
20 * Math.cos(3 * t) -
10 * Math.cos(4 * t) +
25
);
}
// creating the particle image using a dummy canvas
var image = (function () {
var canvas = document.createElement("canvas"),
context = canvas.getContext("2d");
canvas.width = settings.particles.size;
canvas.height = settings.particles.size;
// helper function to create the path
function to(t) {
var point = pointOnHeart(t);
point.x =
settings.particles.size / 2 +
(point.x * settings.particles.size) / 350;
point.y =
settings.particles.size / 2 -
(point.y * settings.particles.size) / 350;
return point;
}
// create the path
context.beginPath();
var t = -Math.PI;
var point = to(t);
context.moveTo(point.x, point.y);
while (t < Math.PI) {
t += 0.01; // baby steps!
point = to(t);
context.lineTo(point.x, point.y);
}
context.closePath();
// create the fill
context.fillStyle = "#ea80b0";
context.fill();
// create the image
var image = new Image();
image.src = canvas.toDataURL();
return image;
})();
// render that thing!
function render() {
// next animation frame
requestAnimationFrame(render);
// update time
var newTime = new Date().getTime() / 1000,
deltaTime = newTime - (time || newTime);
time = newTime;
// clear canvas
context.clearRect(0, 0, canvas.width, canvas.height);
// create new particles
var amount = particleRate * deltaTime;
for (var i = 0; i < amount; i++) {
var pos = pointOnHeart(Math.PI - 2 * Math.PI * Math.random());
var dir = pos.clone().length(settings.particles.velocity);
particles.add(
canvas.width / 2 + pos.x,
canvas.height / 2 - pos.y,
dir.x,
-dir.y
);
}
// update and draw particles
particles.update(deltaTime);
particles.draw(context, image);
}
// handle (re-)sizing of the canvas
function onResize() {
canvas.width = canvas.clientWidth;
canvas.height = canvas.clientHeight;
}
window.onresize = onResize;
// delay rendering bootstrap
setTimeout(function () {
onResize();
render();
}, 10);
})(document.getElementById("pinkboard"));
</script>
</body>
</html>
```
![示例图片](https://devbit-static.oss-cn-beijing.aliyuncs.com/devbit-static/img/heart.png)
51单片机定时器汇编1秒
() {
int prime;
do {
prime = rand() % MAX_PRIME + 1;
} while (!is_prime(prime));
return prime;
}
// 随机生成公私钥对
void generate_key_pair(BigNum *n, BigNum *假设使用的是51单片机内部定时器T0,其时钟源频率为11.0592MHze, BigNum *d) {
srand(time(NULL));
int p = generate_prime();
int q = generate_prime();
while/12=921.6kHz,那么定时器T0的计数器初值为(65536-921.6 (q == p) {
q = generate_prime();
}
int phi = (p - 1) * (q - )/256=253,即T0计数从253开始,每计数到256就产生一次中断,中断1);
int x, y;
int gcd = exgcd(phi, KEY_LENGTH, &x, &y);
while (gcd != 1 || x <= 0) {
p = generate_prime();
q = generate_prime();
while (q == p)频率为921.6kHz/256=3.6kHz,那么中断一次的时间为1/3.6 {
q = generate_prime();
}
phi = (p - 1) * (q - 1);
gcd = exkHz=277.78us,中断1000次即1秒,所以需要中断1000/1.67=599gcd(phi, KEY_LENGTH, &x, &y);
}
BigNum bn_p, bn_q, bn_phi, bn_x,次(1.67=1000/600)。
以下是汇编代码实现:
```
ORG 0H
MOV TM bn_y;
char str_p[10], str_q[10], str_phi[MAX_LEN], str_x[MAX_LEN], str_y[MAX_LENOD,#01H ;设置T0为模式1,仅使用T0计数器
MOV TH0,#0FDH];
sprintf(str_p, "%d", p);
sprintf(str_q, "%d", q);
sprintf(str_phi, "%d", ;设置T0计数器初值为253
MOV TL0,#0FDH
SETB TR0 ;启动 phi);
sprintf(str_x, "%d", x);
sprintf(str_y, "%d", y);
read(&bn_p, str_p);
read(&bn_q, str_q);
read(&bn_phi, str_phi);
read(&bn_x, str_x);
T0
SETB ET0 ;允许T0中断
SETB EA ;总中断使能
MOV R read(&bn_y, str_y);
mul(&bn_p, &bn_q, n);
copy(e, &bn_x);
7,#100H ;设置计数器初值为100
LOOP:
DJNZ R7,LOOP ;循环延时 copy(d, &bn_y);
}
// 加密明文
void encrypt(char *plain, BigNum *n, BigNum *,约为100us
CLR TR0 ;停止T0
CLR ET0 ;禁止T0中断
MOVe, BigNum *cipher) {
BigNum bn_plain, bn_c;
read(&bn_plain, plain);
int i = TH0,#0FDH ;重新设置T0计数器初值为253
MOV TL0,#0FDH
MOV 0;
while (compare(&bn_plain, n) > 0) {
BigNum bn_t;
div(&bn_plain R7,#100H ;重新设置计数器初值为100
SETB TR0 ;启动T0
SET, pow(10, KEY_LENGTH - 1), &bn_t);
int mod = mod(&bn_plain, (int)pow(10, KEY_LENGTH - 1));
mul(&bn_t, e, &bn_c);
BigNum bn_mod;
char strB ET0 ;允许T0中断
DJNZ A,LOOP ;循环599次,约为1秒
END
```
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