This is known as Morton number, which is a specific case of parallel expand which is in turn the reverse of compress right in the following questions What’s the fastest way to pack 32 0/1 values into the bits of a single 32-bit variable? Shift masked bits to the lsb One general solution might be … Read more
The operators |, &, and ~ act on individual bits in parallel. They can be used only on integer types. a | b does an independent OR operation of each bit of a with the corresponding bit of b to generate that bit of the result. The operators ||, &&, and ! act on each … Read more
The answer that Alex Martelli gives in that question is really pretty simple — you can reduce it to: >>> import struct >>> >>> >>> def floatToBits(f): … s = struct.pack(‘>f’, f) … return struct.unpack(‘>l’, s)[0] … … >>> floatToBits(173.3125) 1127043072 >>> hex(_) ‘0x432d5000’ Once you have it as an integer, you can perform any … Read more
Here’s an elegant solution: void getBin(int num, char *str) { *(str+5) = ‘\0’; int mask = 0x10 << 1; while(mask >>= 1) *str++ = !!(mask & num) + ‘0’; } Here, we start by making sure the string ends in a null character. Then, we create a mask with a single one in it (its … Read more
This answer Unset the rightmost set bit tells both how to get and unset rightmost set bit for an unsigned integer or signed integer represented as two’s complement. get rightmost set bit, x & -x // or x & (~x + 1) unset rightmost set bit, x &= x – 1 // or x -= … Read more
Maybe writing the values in hexadecimal (or binary) helps 🙂 enum { kCGDisplayBeginConfigurationFlag = (1 << 0), /* 0b0000000000000001 */ kCGDisplayMovedFlag = (1 << 1), /* 0b0000000000000010 */ kCGDisplaySetMainFlag = (1 << 2), /* 0b0000000000000100 */ kCGDisplaySetModeFlag = (1 << 3), /* 0b0000000000001000 */ kCGDisplayAddFlag = (1 << 4), /* 0b0000000000010000 */ kCGDisplayRemoveFlag = (1 … Read more
Unless you’re using an ancient compiler, it can already handle this level of conversion on its own. That is to say, a modern compiler can and will implement i % 2 using a bitwise AND instruction, provided it makes sense to do so on the target CPU (which, in fairness, it usually will). In other … Read more
First remember that machine words are of fixed size. Say 4, and that your input is: +—+—+—+—+ | a | b | c | d | +—+—+—+—+ Then pushing everything one position to the left gives: +—+—+—+—+ | b | c | d | X | +—+—+—+—+ Question what to put as X? with a … Read more
Bitwise operators Bitwise operators modify the bits of the values involved. A bitwise OR basically ORs together each bit of both the left and right argument. For example: 5 | 2 Would translate to bits/binary as: 101 | 10 Which would result in: 111 Because: 1 || 0 = 1 0 || 1 = 1 … Read more
See two’s complement for the representation of negative integers in many languages. As you can see, -2 is represented by 1111110; if you invert all those bits you get 0000001, i.e. a value of 1.