Data Lab实验记录

实验环境搭建

建议使用Ubuntu作业系统或其他Linux distros

首先从Github拉取该repo複製Lab_Backup中的Lab档软体配置安装gcc: sudo apt-get install gcc(已安装请跳过)安装make: sudo apt -y install make(已安装请跳过)编写脚本(可选)

⚠️使用脚本的目的是为了省略make, make clean, ./btest

开启lab并在资料夹中建立run.sh，，并将下列程式码複製到文件中

#/bin/bashmake cleanmake./btest

完成后每次编译只需要在终端中输入./run.sh即可./dlc -e bits.c查看执行operator的次数

解答

//1/*  * bitXor - x^y using only ~ and &  *   Example: bitXor(4, 5) = 1 *   Legal ops: ~ & *   Max ops: 14 *   Rating: 1 */int bitXor(int x, int y) {  return (~(x&y))&(~(~x&~y));}/*  * tmin - return minimum two's complement integer  *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 4 *   Rating: 1 */int tmin(void) {  return 0x01 << 31;}//2/* * isTmax - returns 1 if x is the maximum, two's complement number, *     and 0 otherwise  *   Legal ops: ! ~ & ^ | + *   Max ops: 10 *   Rating: 1 */int isTmax(int x) {    return (!(~(x^(x+1)))) & (!(!(x^(~0x00000000))));}/*  * allOddBits - return 1 if all odd-numbered bits in word set to 1 *   where bits are numbered from 0 (least significant) to 31 (most significant) *   Examples allOddBits(0xFFFFFFFD) = 0, allOddBits(0xAAAAAAAA) = 1 *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 12 *   Rating: 2 */int allOddBits(int x) {  return !(~(x | 0x55 | (0x55 << 8) | (0x55 << 16) | (0x55 << 24)));}/*  * negate - return -x  *   Example: negate(1) = -1. *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 5 *   Rating: 2 */int negate(int x) {  return (~x) + 0x01;;}//3/*  * isAsciiDigit - return 1 if 0x30 <= x <= 0x39 (ASCII codes for characters '0' to '9') *   Example: isAsciiDigit(0x35) = 1. *            isAsciiDigit(0x3a) = 0. *            isAsciiDigit(0x05) = 0. *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 15 *   Rating: 3 */int isAsciiDigit(int x) {  return !(x + (~(0x30) + 0x01) & (0x01 << 31)) & ((x + (~(0x3a) + 0x01) & (0x01 << 31)) >> 31);}/*  * conditional - same as x ? y : z  *   Example: conditional(2,4,5) = 4 *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 16 *   Rating: 3 */int conditional(int x, int y, int z) {  return (((!x) + (~0x00)) & y) | (((~(!x) + 0x01) & z));}/*  * isLessOrEqual - if x <= y  then return 1, else return 0  *   Example: isLessOrEqual(4,5) = 1. *   Legal ops: ! ~ & ^ | + << >> *   Max ops: 24 *   Rating: 3 */int isLessOrEqual(int x, int y) {  int a = (x >> 31) & 0x1; // check +/-  int b = (y >> 31) & 0x1; // check +/-  int c1 = (a & (!b)); // positive overflow  int c2 = ((!a) & b); // negative overflow  int e = y + ((~x) + 1);  int flag = e >> 31; // normal minus operationreturn c1 | ((!c2) & (!flag));}//4/*  * logicalNeg - implement the ! operator, using all of  *              the legal operators except ! *   Examples: logicalNeg(3) = 0, logicalNeg(0) = 1 *   Legal ops: ~ & ^ | + << >> *   Max ops: 12 *   Rating: 4  */int logicalNeg(int x) {  return ((((x ^ (~(0x01 << 31))) + 0x01) >> 31) & 0x01) & (((x ^ (0x01 << 31)) >> 31) & 0x01);}/* howManyBits - return the minimum number of bits required to represent x in *             two's complement *  Examples: howManyBits(12) = 5 *            howManyBits(298) = 10 *            howManyBits(-5) = 4 *            howManyBits(0)  = 1 *            howManyBits(-1) = 1 *            howManyBits(0x80000000) = 32 *  Legal ops: ! ~ & ^ | + << >> *  Max ops: 90 *  Rating: 4 */int howManyBits(int x) {    int b16, b8, b4, b2, b1, b0;    int flag = x >> 31;    x = (~flag & x) | (flag & ~x);    b16 = !!(x >> 16) << 4;    x >>= b16;    b8 = !!(x >> 8) << 3;    x >>= b8;    b4 = !!(x >> 4) << 2;    x >>= b4;    b2 = !!(x >> 2) << 1;    x >>= b2;    b1 = !!(x >> 1);    x >>= b1;    b0 = x;  return b0 + b1 + b2 + b4 + b8 + b16 +1;}//float/*  * floatScale2 - Return bit-level equivalent of expression 2*f for *   floating point argument f. *   Both the argument and result are passed as unsigned int's, but *   they are to be interpreted as the bit-level representation of *   single-precision floating point values. *   When argument is NaN, return argument *   Legal ops: Any integer/unsigned operations incl. ||, &&. also if, while *   Max ops: 30 *   Rating: 4 */unsigned floatScale2(unsigned uf) {  int flag = (uf >> 31) & 0x01;  int exp = ((uf >> 23) & 0xff);  int frac = uf & 0x7fffff;  // 0  if(exp == 0 && frac == 0){    return uf;  }  // infinite or NaN  if(exp == 0xff){    return uf;  }  // denormalize  if(exp == 0){    frac <<= 1;    return (flag << 31) | (exp << 23) | frac;  }  // normalize  uf += (0x01 << 23);  return uf;}/*  * floatFloat2Int - Return bit-level equivalent of expression (int) f *   for floating point argument f. *   Argument is passed as unsigned int, but *   it is to be interpreted as the bit-level representation of a *   single-precision floating point value. *   Anything out of range (including NaN and infinity) should return *   0x80000000u. *   Legal ops: Any integer/unsigned operations incl. ||, &&. also if, while *   Max ops: 30 *   Rating: 4 */int floatFloat2Int(unsigned uf) {  int flag = (uf >> 31) & 0x01;  int exp = ((uf >> 23) & 0xff);  int frac = uf & 0x7fffff;  int n = exp - 127;  // 0  if(exp == 0 && frac == 0){    return 0;  }  // infinite or NaN  if(n >= 32){    return 0x80000000u;  }  // denormalize  if(exp == 0){    return 0;  }  // normalize  float base = 1.0;    flag = (flag == 0x01) ? -1 : 1;  if((frac >> 22) & 0x01 == 0x01){    base += 0.5;  }  if(n > 0){    return (int)(flag * base * (1 << n));  }else if(n == 0){      return (int) flag * base;  }else{    return (int)(flag * base * (1 >> (-n)));  }}/*  * floatPower2 - Return bit-level equivalent of the expression 2.0^x *   (2.0 raised to the power x) for any 32-bit integer x. * *   The unsigned value that is returned should have the identical bit *   representation as the single-precision floating-point number 2.0^x. *   If the result is too small to be represented as a denorm, return *   0. If too large, return +INF. *  *   Legal ops: Any integer/unsigned operations incl. ||, &&. Also if, while  *   Max ops: 30  *   Rating: 4 */unsigned floatPower2(int x) {  if(x > 127){    return (0xff << 23);  }    if(x < -127){      return 0;  }  return (127 + x) << 23;}

资源

https://github.com/WeiLin66/CMU-15-213/tree/main/Labs/data-lab