bitwise-operators

问题 How do I write NOT Operation for the Risc-V (Assembly Language)? If there's no NOT instruction, how do you achieve the same thing? 回答1: Like MIPS and some other architectures, RISC V does not provide dedicated instructions for many things, including two-operand unary operations, as these operations can be had using their three-operand format, usually with x0 as the third operand, but sometimes constant 1 or -1 as the third operand. For convenience, the assembler will accept what are called

问题 How do I write NOT Operation for the Risc-V (Assembly Language)? If there's no NOT instruction, how do you achieve the same thing? 回答1: Like MIPS and some other architectures, RISC V does not provide dedicated instructions for many things, including two-operand unary operations, as these operations can be had using their three-operand format, usually with x0 as the third operand, but sometimes constant 1 or -1 as the third operand. For convenience, the assembler will accept what are called

问题 This question already has answers here : What do these operators mean (** , ^ , %, //)? [closed] (3 answers) Closed 2 years ago . Why is ^ not squaring in Python? I know exponentiation is ** instead, but what exactly is ^ and why wasn't that operator used instead? For example 2^2=0 , 3^2=1 . 回答1: The ^ operator was already used for bitwise xor. >>> x = 42; format(x, '08b') '00101010' >>> y = 137; format(y, '08b') '10001001' >>> z = x ^ y; format(z, '08b') '10100011' That leaves the old

问题 This question already has answers here : What do these operators mean (** , ^ , %, //)? [closed] (3 answers) Closed 2 years ago . Why is ^ not squaring in Python? I know exponentiation is ** instead, but what exactly is ^ and why wasn't that operator used instead? For example 2^2=0 , 3^2=1 . 回答1: The ^ operator was already used for bitwise xor. >>> x = 42; format(x, '08b') '00101010' >>> y = 137; format(y, '08b') '10001001' >>> z = x ^ y; format(z, '08b') '10100011' That leaves the old

问题 I am trying to translate some js code into python and having trouble converting bitwise operators. I already introduced ctypes.c_int in python but the results still do not match. For the >>> in js I used as suggested here. A minimal example of my (not working) code: Javascript: let R = [7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 7, 12, 17, 22, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 5, 9, 14, 20, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 4, 11, 16, 23, 6, 10, 15, 21, 6, 10, 15, 21, 6,

问题 Let's say I have: byte[] data = new byte[] { 1, 212, 29, 144 }; The only way I'm able to figure out to do a bitwise AND & is by first converting the byte[] to a uint: if ((BitConverter.ToUInt32(data,0)) & 0x7) == 1) { //If the last 3 bits are ...111, then do something } This seems ugly. Is there a better way to perform bitwise operations on a byte[] without having to convert to a UInt? Thanks. 回答1: No, there no direct support in .Net for bit operations on byte arrays. You can convert to

问题 The operator '&' can be used in both of following way int a; scanf("%d",&a); and printf("%d",1&2) . But different behaviour (for first as address operator and second time as bit-wise operator). I know operator overloading is not there in C. Then how it works ?. Also highlight for c++. 回答1: In "C" language, operators have different meaning when they are used as prefix to expression, suffix to expression or "infix" (between two expressions). Consider '*', which performs multiplication as 'infix

问题 I've been writing a program in C to move the first 4 bits of a char to the end and the last 4 to the start. For most values it works normally, as well as the reverse operation, but for some values, as 8, x, y, z, it gives as result a 32 bit value. Values checked through printing hex value of the variable. Can anybody explain why this is happening? #include <stdio.h> #include <stdlib.h> int main() { char o, f,a=15; scanf("%c",&o); printf("o= %d\n",o); f=o&a; o=o>>4; printf("o= %d",o); o=o|(f<

问题 I am trying to eliminate an IF statement whereby if I receive the number 32 I would like a '1', but any other number I would like a '0'. 32 is 0010 0000 so I thought about XOR-ing my input number with 1101 1111. Therefore if I get the number 32 I end up with 1111 1111. Now is there any way of AND-ing the individual bits (1111 1111), because if one of my XOR results is a 0, it means my final AND-ed value is 0, otherwise its a 1? EDIT: Using GCC, not Intel compiler (because I know there are a

问题 I know that StackOverflow is not meant for asking code to other persons, but let me speak. I am trying to implement some AES functions in CUDA C++ device code. While trying to implement the left bytewise rotate operator, I was disconcerted to see that there was no native SIMD intrisic for that. So I began a naive implementation, but....it's huge, and while I haven't tried it yet, it just won't be fast because of the expensive unpacking/packing... So, is there a mean to do a per byte bit