(BQ) Part 2 book "Computer organization and design fundamentals" has contents: Binary operation applications, memory cells, state machines, memory organization, memory hierarchy, serial protocol basics, introduction to processor architecture,.and other contents. | CHAPTER NINE Binary Operation Applications Our discussion so far has focused on logic design as it applies to hardware implementation. Frequently software design also requires the use of binary logic. This section presents some higher-level binary applications, ones that might be found in software. These applications are mostly for error checking and correction, but the techniques used should not be limited to these areas. Bitwise Operations Most software performs data manipulation using mathematical operations such as multiplication or addition. Some applications, however, may require the examination or manipulation of data at the bit level. For example, what might be the fastest way to determine whether an integer is odd or even? The method most of us are usually taught to distinguish odd and even values is to divide the integer by two discarding any remainder then multiply the result by two and compare it with the original value. If the two values are equal, the original value was even because a division by two would not have created a remainder. Inequality, however, would indicate that the original value was odd. Below is an if-statement in the programming language C that would have performed this check. if(((iVal/2)*2) == iVal) // This code is executed for even values else // This code is executed for odd values Let's see if we can't establish another method. As we discussed in Chapter 3, a division by two can be accomplished by shifting all of the bits of an integer one position to the right. A remainder occurs when a one is present in the rightmost bit, ., the least significant bit. A zero in this position would result in no remainder. Therefore, if the LSB is one, the integer is odd. If the LSB is zero, the integer is even. This is shown with the following examples. 165 166 Computer Organization and Design Fundamentals 3510 = 001000112 9310 = 010111012 12410 = 011111002 3010 = 000111102 This reduces our odd/even detection down to an .
