0
The "twos complement" is that marvelous manipulation of bits in computer binary code that allows the computer to subtact by adding. It would be difficult to explain the whole picture, but computers can really do nothing but add. So the natural question is, how do they then calculate differences? Two's complement is the answer.
Add your answer:
Earn +20 pts
What is meant by ones-compliment of a decimal number?
One-complement applies to binary values, not decimal values. Therefore when we say the ones-complement of a decimal value we mean convert the value to binary, invert all the bits (the ones-complement), then convert the result back to decimal. For example, the decimal value 42 has the following representation in 8-bit binary: 00101010 If we invert all the bits we get 11010101 which is 213 decimal. Thus 213 is the ones-complement of 42, and vice versa. However, it's not quite as straightforward as that because some (older) systems use ones-complement notation to represent signed values, such that 11010101 represents the decimal value -42. The problem with this notation is that the ones-complement of 00000000 is 11111111 which means the decimal value 0 has two representations, +0 and -0 respectively. In the real-world, zero is neither positive nor negative. To resolve this problem, modern systems use twos-complement to represent signed values. The twos-complement of any value is simply the ones-complement plus one. Thus the ones-complement of 42 becomes -43, therefore the twos-complement of 42 is -43+1 which is -42. Thus -42 is represented by the binary value 11010110 in twos-complement notation. With twos-complement, there is only one representation for the value 0. This is because the ones-complement of 00000000 is 11111111 and if we add 00000001 we get 00000000. Note that we don't get 100000000 because the result cannot have any more bits than were in the original value. When an "overflow" occurs, we cycle back to zero. As a result, incrementing and decrementing signed values has exactly the same logic as incrementing or decrementing unsigned values and flipping the sign of any value is only slightly more complicated by the extra addition operation. However, flipping the sign of a value is a much rarer operation than counting so the cost is trivial compared to the cost of counting operations using ones-complement (because there are two values for zero). Note that ones-complement notation allows an 8-bit value to store signed values in the range -127 to +127, whereas twos-complement allows a range of -128 to +127 (through the elimination of the extra zero). But in unsigned notation, both allow the same range: 0 to 255. Although we rarely encounter ones-complement notation, it is important to keep in mind that not all systems use twos-complement notation, particularly when working with low-level but portable programming languages. This is the reason why both the C and the C++ standards state that the range of an 8-bit signed value is only guaranteed to store values in the range -127 to +127.
How do you write a program to determine whether a number is odd or even counter?
For positive integers, if the least significant bit is set then the number is odd, otherwise it is even. For negative integers in twos-complement notation, if the least significant bit is set then the number is odd, otherwise it is even. Twos-complement is the normal notation, allowing a range of -128 to +127 in an 8-bit byte. For negative integers in ones-complement notation, if the least significant bit is set then the number is even, otherwise it is odd. Ones-complement is less common, allowing a range of -127 to +127 in an 8-bit byte, where 11111111 is the otherwise non-existent value -0 (zero is neither positive nor negative). Ones-complement allows you to change the sign of a value simply by inverting all the bits. Twos-complement is the same as ones-complement but we also add one. Thus the twos complement of 0 is 0 because 11111111 + 1 is 0 (the overflowing bit is ignored). 11111111 then becomes -1 rather than the non-existent -0.
What is the binary complement 8 bit representation for negative 19?
8-bit 2s complement representation of -19 is 11101101 For 1s complement invert all the bits. For 2s complement add 1 to the 1s complement: With 8-bits: 19 � 0001 0011 1s � 1110 1100 2s � 1110 1100 + 1 = 1110 1101
Signed binary subtraction 000000111001-111010000101 equals 000110101110 right?
Wrong. You don't say whether you are using ones-complement notation or twos-complement notation, but in either case you'd be wrong. Your answer of 000110101110 is 430 decimal, but the correct answer is 435 or 436 depending on which notation you use. Ones-complement notation: 000000111001 - 111010000101 = 000110110011 Decimal equivalent: 57 - (-378) = 57 + 378 = 435 Twos-complement notation: 000000111001 - 111010000101 = 000110110100 Decimal equivalent: 57 - (-379) = 57 + 379 = 436 Note that in ones-complement, converting the sign of any value simply inverts all the bits. So if we invert 111010000101 we get 000101111010 which is 378, thus the original signed value was -378. In twos complement we invert all the bits (as per ones-complement) and add 1, so 000101111010 + 1 is 000101111011 is 379, thus the original signed value was -379. QED.
How do you write a basic program find whether number is even or odd if even display its square and if odd display its cube?
Divide that number into 2 using modulus division. Modulus division get the remainder of the division. If it has no remainders, then it's an even number. If not, then it's an odd number. Here's a pseudo code of the program. ALGORITHM ODD_EVEN INPUT (number) IF (number MOD 2 == 0) THEN DISPLAY ("Even") ELSE DISPLAY ("Odd") END IF END ODD_EVEN Amendment: You did ask for a BASIC program: 10 INPUT X: IF X = 999 THEN STOP 20 PRINT X;: IF X/2 = INT(X/2) THEN PRINT "EVEN" ELSE PRINT "ODD" 30 GOTO 10
What is the number 0111111111111111 in twos complement?
100000000000001
The twos complement of 11001101 is?
00110011 is the 2's complement for this unsigned number and 10110011 if this is a signed number
How do you programme Twos complement in binary in c?
int complement (int n) { return -n; } or int complement (int n) { return ~n+1; } both does the same thing.
10 Why is twos complement usually used to represent integers?
The advantage of the two's complement method is that the procedure for adding or subtracting numbers is the same, whether the numbers are positive or negative. This makes the hardware for managing these numbers simpler.
Why 2's complement representation the best choice?
Because addition and subtraction in 2's complement representation do not need to care about sign.
How do you find twos compliment of 00h in 8085 program?
You find the two's complement of 00H the same way you find it for any other number. You complement the bits and then you add 1. In the case of 00H, this results in 00H. That is no surprise, because -0 is the same as +0, and two's complement representation was chosen to do just that, as well as to make the physical addition of signed and unsigned numbers to be the same.
What is meant by ones-compliment of a decimal number?
One-complement applies to binary values, not decimal values. Therefore when we say the ones-complement of a decimal value we mean convert the value to binary, invert all the bits (the ones-complement), then convert the result back to decimal. For example, the decimal value 42 has the following representation in 8-bit binary: 00101010 If we invert all the bits we get 11010101 which is 213 decimal. Thus 213 is the ones-complement of 42, and vice versa. However, it's not quite as straightforward as that because some (older) systems use ones-complement notation to represent signed values, such that 11010101 represents the decimal value -42. The problem with this notation is that the ones-complement of 00000000 is 11111111 which means the decimal value 0 has two representations, +0 and -0 respectively. In the real-world, zero is neither positive nor negative. To resolve this problem, modern systems use twos-complement to represent signed values. The twos-complement of any value is simply the ones-complement plus one. Thus the ones-complement of 42 becomes -43, therefore the twos-complement of 42 is -43+1 which is -42. Thus -42 is represented by the binary value 11010110 in twos-complement notation. With twos-complement, there is only one representation for the value 0. This is because the ones-complement of 00000000 is 11111111 and if we add 00000001 we get 00000000. Note that we don't get 100000000 because the result cannot have any more bits than were in the original value. When an "overflow" occurs, we cycle back to zero. As a result, incrementing and decrementing signed values has exactly the same logic as incrementing or decrementing unsigned values and flipping the sign of any value is only slightly more complicated by the extra addition operation. However, flipping the sign of a value is a much rarer operation than counting so the cost is trivial compared to the cost of counting operations using ones-complement (because there are two values for zero). Note that ones-complement notation allows an 8-bit value to store signed values in the range -127 to +127, whereas twos-complement allows a range of -128 to +127 (through the elimination of the extra zero). But in unsigned notation, both allow the same range: 0 to 255. Although we rarely encounter ones-complement notation, it is important to keep in mind that not all systems use twos-complement notation, particularly when working with low-level but portable programming languages. This is the reason why both the C and the C++ standards state that the range of an 8-bit signed value is only guaranteed to store values in the range -127 to +127.
Twos complement of a given 3 or more bit binary number of non-zero magnitude is the same the original number if all bits except the?
ANSWER: MSB IS 1 In the 2's complement representation, the 2's complement of a binary number is obtained by first finding the one's complement (flipping all the bits), and then adding 1 to the result. This representation is commonly used to represent signed integers in binary form. Now, if all bits except the sign bit are the same, taking the 2's complement of the binary number will result in the negative of the original number. The sign bit (the leftmost bit) is flipped, changing the sign of the entire number. For example, let's take the 4-bit binary number 1101 The 2's complement would be obtained as follows: Find the one's complement: 0010 Add 1 to the one's complement: 0011
How do you write a program to determine whether a number is odd or even counter?
For positive integers, if the least significant bit is set then the number is odd, otherwise it is even. For negative integers in twos-complement notation, if the least significant bit is set then the number is odd, otherwise it is even. Twos-complement is the normal notation, allowing a range of -128 to +127 in an 8-bit byte. For negative integers in ones-complement notation, if the least significant bit is set then the number is even, otherwise it is odd. Ones-complement is less common, allowing a range of -127 to +127 in an 8-bit byte, where 11111111 is the otherwise non-existent value -0 (zero is neither positive nor negative). Ones-complement allows you to change the sign of a value simply by inverting all the bits. Twos-complement is the same as ones-complement but we also add one. Thus the twos complement of 0 is 0 because 11111111 + 1 is 0 (the overflowing bit is ignored). 11111111 then becomes -1 rather than the non-existent -0.
What is the binary complement 8 bit representation for negative 19?
8-bit 2s complement representation of -19 is 11101101 For 1s complement invert all the bits. For 2s complement add 1 to the 1s complement: With 8-bits: 19 � 0001 0011 1s � 1110 1100 2s � 1110 1100 + 1 = 1110 1101
What is the format of the integer when held in the PC?
There is no single format. Different architectures and platforms store data in different ways. An integer's representation depends on its length (in bytes), the byte-order (little-endian or big-endian) and whether they are signed or unsigned. If signed, they may be represented using either ones-complement or (more commonly) twos-complement. Most programming languages provide several integer types, however the actual representation of each of these types is machine-dependent and, therefore, implementation-dependent, even in the same language.
What does four twos in a row stand for?
Four twos in a row is a term used in probability. It is also used in card games. It means that the player has dropped two suits of twos consecutively.
