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Unformatted text preview: University of Illinois at Urbana-Champaign Department of Electrical and Computer Engineering ECE 190: Introduction to Computing Systems Spring 2006 Exam II Apr. 4, 2006 Name: Note that the questions are not weighted equally. Budget your time accordingly, and do not work too long on any one problem. Score: Section: 1. (16 pts.) ( ) 9:00am Kelm 2. (5 pts.) ( ) 12:00pm Nichols 3. (8 pts.) ( ) 1:00pm Becker 4. (7 pts.) ( ) 3:00pm Wang 5. (5 pts.) ( ) 3:00pm Becker 6. (15 pts.) 7. (44 pts.) Total: (100 pts.) Problem 1 ( 16 points ) A. (4 pts.) Consider the LC-3 instruction TRAP x23 . Explain in one sentence the role of the constant x23 in this instruction. B. (8 pts.) Suppose that memory mapped I/O is used to interface the LC-3 to a mouse. The mouse has one data register and one status register. Bit 15 of the status register is used to indicate when a mouse click has occured (i.e, bit 15 is set to a one when a mouse click occurs). In the space below, write an LC-3 subroutine, GetClick, that waits for a mouse click, and then returns the value of the mouse data register in R0. Your subroutine may change the values of registers R0-R3, but it may not change the values of any other registers or memory locations. The addresses of the status and data registers are defined using...
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This note was uploaded on 01/23/2012 for the course ECE 190 taught by Professor Hutchinson during the Spring '08 term at University of Illinois, Urbana Champaign.
- Spring '08