256K*4位的MB81C4256引脚示意图

很抱歉，作为语言模型AI，我无法展示图片或图示。但是，我可以告诉您MB81C4256是一款32K x 8位的静态RAM芯片，具有28个引脚，其中包括8个数据引脚（D0-D7）、13个地址引脚（A0-A12）、一个输出使能引脚（OE#）、一个写使能引脚（WE#）、一个片选引脚（CE#）和一个电源引脚（Vcc）。这是一款常见的RAM芯片，经常用于嵌入式系统和电子设备中。

相关问题

MB81C4256引脚示意图

MB81C4256引脚示意图如下所示：

+---+
A12 |1 24| Vcc
A7 |2 23| A11
A6 |3 22| A9
A5 |4 21| A8
A4 |5 20| A10
A3 |6 19| DQ7
A2 |7 18| DQ6
A1 |8 17| DQ5
A0 |9 16| DQ4
DQ0 |10 15| DQ3
DQ1 |11 14| DQ2
WE |12 13| RAS
+---+

其中，Vcc为芯片电源，WE为写使能端，RAS为行地址选择端，DQ0-DQ7为数据输入输出端，A0-A12为地址输入端。

SHA256算法C++

您好！SHA-256（Secure Hash Algorithm 256-bit）是一种常用的哈希算法，用于将任意长度的数据转换为固定长度（256位）的哈希值。以下是一个使用C语言实现SHA-256算法的示例代码：

#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>

#define ROTR(x, n) (((x) >> (n)) | ((x) << (32 - (n))))

uint32_t ch(uint32_t x, uint32_t y, uint32_t z) {
    return (x & y) ^ (~x & z);
}

uint32_t maj(uint32_t x, uint32_t y, uint32_t z) {
    return (x & y) ^ (x & z) ^ (y & z);
}

uint32_t ep0(uint32_t x) {
    return ROTR(x, 2) ^ ROTR(x, 13) ^ ROTR(x, 22);
}

uint32_t ep1(uint32_t x) {
    return ROTR(x, 6) ^ ROTR(x, 11) ^ ROTR(x, 25);
}

uint32_t sig0(uint32_t x) {
    return ROTR(x, 7) ^ ROTR(x, 18) ^ (x >> 3);
}

uint32_t sig1(uint32_t x) {
    return ROTR(x, 17) ^ ROTR(x, 19) ^ (x >> 10);
}

void sha256(uint8_t *message, size_t len, uint8_t *hash) {
    uint32_t h[8] = {
        0x6a09e667,
        0xbb67ae85,
        0x3c6ef372,
        0xa54ff53a,
        0x510e527f,
        0x9b05688c,
        0x1f83d9ab,
        0x5be0cd19
    };

    uint32_t k[64] = {
        0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
        0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
        0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
        0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
        0xe49b69c1, 0xefbe4786, 0xfc19dc6, 0x240ca1cc,
        0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
        0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
        0xc6e00bf3, 0xd5a79147, 0x6ca6351, 0x14292967,
        0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
        0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
        0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
        0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
        0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
        0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
        0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
        0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
    };

    size_t new_len = ((((len + 8) / 64) + 1) * 64) - 8;
    uint8_t *msg = (uint8_t *)malloc(new_len + 64);
    memcpy(msg, message, len);
    msg[len] = 128;

    for (size_t i = len + 1; i < new_len; ++i) {
        msg[i] = 0;
    }

    uint64_t bit_len = len * 8;
    memcpy(msg + new_len, &bit_len, sizeof(uint64_t));

    for (size_t offset = 0; offset < new_len; offset += 64) {
        uint32_t w[64];

        for (size_t i = 0; i < 16; ++i) {
            w[i] = (msg[offset + i * 4] << 24) |
                   (msg[offset + i * 4 + 1] << 16) |
                   (msg[offset + i * 4 + 2] << 8) |
                   (msg[offset + i * 4 + 3]);
        }

        for (size_t i = 16; i < 64; ++i) {
            w[i] = sig1(w[i - 2]) + w[i - 7] + sig0(w[i - 15]) + w[i - 16];
        }

        uint32_t a = h[0];
        uint32_t b = h[1];
        uint32_t c = h[2];
        uint32_t d = h[3];
        uint32_t e = h[4];
        uint32_t f = h[5];
        uint32_t g = h[6];
        uint32_t h_ = h[7];

        for (size_t i = 0; i < 64; ++i) {
            uint32_t t1 = h_ + ep1(e) + ch(e, f, g) + k[i] + w[i];
            uint32_t t2 = ep0(a) + maj(a, b, c);
            h_ = g;
            g = f;
            f = e;
            e = d + t1;
            d = c;
            c = b;
            b = a;
            a = t1 + t2;
        }

        h[0] += a;
        h[1] += b;
        h[2] += c;
        h[3] += d;
        h[4] += e;
        h[5] += f;
        h[6] += g;
        h[7] += h_;
    }

    for (size_t i = 0; i < 8; ++i) {
        hash[i * 4] = (h[i] >> 24) & 0xFF;
        hash[i * 4 + 1] = (h[i] >> 16) & 0xFF;
        hash[i * 4 + 2] = (h[i] >> 8) & 0xFF;
        hash[i * 4 + 3] = h[i] & 0xFF;
    }

    free(msg);
}

int main() {
    uint8_t message[] = "Hello, world!";
    uint8_t hash[32];

    sha256(message, sizeof(message) - 1, hash);

    printf("SHA-256 Hash: ");
    for (size_t i = 0; i < 32; ++i) {
        printf("%02x", hash[i]);
    }
    printf("\n");

    return 0;
}

这段代码实现了SHA-256算法的核心部分，可以将输入的消息（message）转换为对应的SHA-256哈希值。运行示例代码会输出消息 "Hello, world!" 的SHA-256哈希值。请注意，此处的代码仅作为参考，实际应用中建议使用经过充分测试和验证的库或工具来计算SHA-256哈希。