Hw 4 sol - EEL 3801 - Computer Organization Spring, 2010 HW...

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EEL 3801 - Computer Organization Spring, 2010 HW #4 Solution 4.1 After reading the input data, it is necessary to clear the input status flag before the program begins a new read operation. Otherwise, the same input data would be read a second time.
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4.2 The ASCII code for the numbers 0 to 9 can be obtained by adding $30 to the number. The values 10 to 15 are represented by the letters A to F, whose ASCII codes can be obtained by adding $37 to the corresponding binary number. Assume the output status bit is b4 in register Status, and the output data register is Output.
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4.4 A subroutine is called by a program instruction to perform a function needed by the calling program. An interrupt-service routine is initiated by an event such as an input operation or a hardware error. The function it performs may not be at all related to the program being executed at the time of interruption. Hence, it must not affect any of the data or status information relating to that program. 4.8
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This note was uploaded on 04/02/2010 for the course EEL 3801 taught by Professor Froosh during the Spring '08 term at University of Central Florida.

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Hw 4 sol - EEL 3801 - Computer Organization Spring, 2010 HW...

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