With binary we need a method of representing negative numbers. The simplest way to do this (though not the best) is to use the and method. In sign and magnitude binary, a number is expressed using a combination of a sign bit and a magnitude (the absolute value of the number). They combine together to make the full signed number. The sign bit indicates positive (0) or negative (1) and the rest of the number is just a normal number. In the example above, the number -25 is represented by the sign bit (1) and the absolute value (11001).
Sign and Magnitude has two key issues. The first issue is that there are representations of zero—one positive (all bits set to 0) and one negative (sign bit set to 1, all other bits set to 0). This can cause confusion and lead to errors in calculations and comparisons. For example, 0000 = 0; 1000 = . The second issue is that performing arithmetic operations, such as and subtraction, on sign and magnitude numbers can be complex. Additional logic is required to handle the signs, which makes the operations more difficult and processor intensive to implement using circuitry.
Keywords
0 | sign | binary | digital | addition | magnitude | two |
