twos-complement

问题 I am trying to add 24 to 10 in 2's complement. I found 24 in 2's complement to be: 011000 and 10 in 2's complement to be 001010. When I add the two together I get: 100010. The result is a negative number. Is this an example of overflow? Is it not possible to add 24 to 10 in 2's complement? 回答1: If you only have 6 bits, then yes, it is an overflow. The reason is that 6-bit 2's complement can only store numbers -32..31 and your desired result, 34 , is outside that range. If you had, say, 8 bits

问题 C++20 will specify that signed integral types must use two's complement. This doesn't seem like a big change given that (virtually?) every implementation currently uses two's complement. But I was wondering if this change might shift some "undefined behaviors" to be "implementation defined" or even "defined." Consider, the absolute value function, std::abs(int) and some of its overloads. The C++ standard includes this function by reference to the C standard, which says that the behavior is

问题 This question already has answers here : 2's complement hex number to decimal in java (3 answers) Closed 6 years ago . I know that converting a decimal to binary with Integer.toBinaryString(355) = 0000000101100011 and Integer.toBinaryString(-355) = 1111111010011101 (where I take the lower 16 bits of the 32 bit result). What I would like to do is the other way and take a 16-bit twos's complement binary string and to convert to decimal. i.e. 0000000000110010 = 50 1111111111001110 = -50 Rather

问题 I'm trying to solve some exercises, I have to shift a 8-bit vector named A into 2A (A+A). my soluction for this is: (A(7) and '1') & A(6 downto 0) & '0'; after this I made a two's complement of A in this way: entity complementare is port(a: in std_logic_vector(7 downto 0); b: out std_logic_vector(7 downto 0)); end complementare; architecture C of complementare is signal mask, temp: std_logic_vector(7 downto 0); component ripplecarry8bit is port(a,b: std_logic_vector(7 downto 0); cin: in std

问题 I have just learnt that to get the formula to find the 1st Complement is -x = 2^n - x - 1 I have managed to apply it on a binary case: -00001100 (base 2) = 2^8 - 12 - 1 = 243 = 11110011 (1s) However, when I try to apply the same formula to a base 5 number, -1042 (base 4) = 5^4 - 1042 - 1 = 625 - 1042 - 1 = - 400 (which is not the answer) Can some one help me out here? Thanks 回答1: you cannot calculate any formula with numbers in 2 different bases, you have to use their decimal representation

问题 The type int is 4-byte long and I wrote a little procedure in C under Ubuntu to print the number I've just input. When I input 2147483648, i.e. 2^31, it prints 2147483647 rather than -1. The same thing happens when I input any number larger than 2147483647. Why doesn't it overflow to -1 as I learnt form book but seems like truncated to INT_Max and what happened in the bits level? #include <stdio.h> int main(){ int x; scanf("%d",&x); printf("%d\n",x); } I made a mistake. INT_Max+1 should equal

问题 I have a routine that is collecting a hex value via SNMP. Here is a real collection from my bash script 08 01 18 00 FF FF. The value is base on expr $((16#${array[4]})) - $((16#${array[5]})) so the results are 0, how do I introduce two is complement? The correct value for expr $((16#${array[4]})) - $((16#${array[5]})) is -1 based on the example I am working on. 回答1: For convenience, let's create a bash function: twos() { x=$((16#$1)); [ "$x" -gt 127 ] && ((x=x-256)); echo "$x"; } Now: $ twos

问题 How to detect an int sign-ness in C? This question is mostly of historical machines. What I am asking how to distinguish if an integer is 0 or -0. In 1's complement and sign/magnitude int encoding, both a 0 (or +0) and -0 are possible. The simple sign bit test is to compare against 0 . int x; printf("sign bit is %s\n", (x < 0) ? "set" : "not set"); But this fails in 1's complement and sign magnitude when x is -0 . 1st Candidate approach: Mask test. As C defines that an int must have a sign

问题 How do I add and subtract 16 bit floating point half precision numbers? Say I need to add or subtract: 1 10000 0000000000 1 01111 1111100000 2’s complement form. 回答1: Assuming you are using a denormalized representation similar to that of IEEE single/double precision, just compute the sign = (-1)^S, the mantissa as 1.M if E != 0 and 0.M if E == 0, and the exponent = E - 2^(n-1), operate on these natural representations, and convert back to the 16-bit format. sign1 = -1 mantissa1 = 1.0

问题 so I think questions like this have been asked before but I'm having quite a bit of trouble getting this implemented. I'm dealing with CSV files that contain floating points between -1 and 1. All of these floating points have to be converted to 16 bit 2s complement without the leading '0b'. From there, I will convert that number to a string representation of the 2s complement, and all of those from the CSV will be written will be written to a .dat file with no space in between. So for example