EEL 4511 Dr. Gugel LAST NAME FIRST NAME Fall 2015, Real-time DSP Exam #1

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1 EEL 4511 Dr. Gugel LAST NAME FIRST NAME Fall 2015, Real-time DSP Exam #1 Open book and open notes, 60 minute examination, No electronic devices are permitted. Page 1 33 points Page 2 17 points Page 3 10 points Page 4 18 points Page 5 22 points TOTAL out of For the following code, show the values of the flags and registers after the compare and add instructions. AH, #0x789A AL, #0x8CAB CMP AH,AL ;after this instruction executes show the contents of Z, C, V and N below. (7 pt.) AH = Hex C = V = N = Z = AH, #0x8CAB AL, #0x789A SUB AH, AL ;after this instruction executes show the contents of AL, C, V and N below. (8 pt.) AH = Hex C = V = N = Z = For the code in the Appendix, answer the following questions. 2. At load time, what addresses will be modified in memory? (4 pt.) 3. At run time what addresses are modified in memory? (4 pt.) 4. What is the effective address for the instruction on Line 23? (2 pt.) 5. What is the effective address for the instruction on Line 27? (2 pt.) 6. What is the effective address for the instruction on Line 38? (2 pt.) 7. What is the opcode for a Long Call to a subroutine? (2 pt.) 8. What is the operand for the instruction on Line 26? (2 pt.) Note: It is not "0000". I am looking for the value that will be in memory at load time.

2 9. What is the content of stack memory after the subroutine executes and we have returned back to the unconditional branch instruction? (6 pt.) Address (Hex) Data (Hex) 10. What is the contents of 0x8000-0x8004 after the subroutine executes. Use XX for unknown values. (5 pt.) 0x8000 Hex 0x8001 Hex 0x8002 Hex 0x8003 Hex 0x8004 Hex A student would like to create a program to perform the following task. Read in an 8 bit signed number on GPIO7:0 (where GPIO0 is the LSB) then sign extend it to 16 bits signed and then finally echo the result back out to DSP pins GPIO23:8 (where GPIO8 is the LSB). 11. Write the code to properly initialize the GPIO for the proper input and output pins. (6 pt.) Page 2 Page Score =

3 12. Write a program to read GPIO7:0, sign extension to 16 bits and output to GPIO23:8. (10 pt.) The NSA is interested in intercepting text files that contain the word "ISIS". A student has written a program that moves text from an message into external SRAM that has been placed from 0x4000-0x4FFF (using -CS0). Your task is to write a program that searches this entire memory and counts the number of times that the word "ISIS" is used. Assume that a particular address only contains one ASCII character (typical text message) and that the final count should be written to Data memory as shown below..sect ".cinit" ;Data Section, assumed to start at 0x8000 total_count.word 0 Page 3 Page Score =

4 14. Create a concise short flow chart for your program that counts the number of "ISIS" characters. (8 pt.) 15. If we assume that the 0x4000-0x4FFF in DSP Memory was created with 2Kx8 SRAMs, identify how many SRAMs will be required and draw the decode circuitry required for the 2Kx8 SRAMs. (10 pt.) Page 4 Page Score =

5 16. Write the code to count the number of "ISIS" words found in the 0x4000-0x4FFF SRAM. (22 pt.) Page 5 Page Score =

6 Appendix. Typical DSP Assembly Program 7 ;***************************** Program Constants *** Lines 1-6 deleted for brevity purposes v_len.set 0x4 ;length of test vector stack_addr.set 0x400 ;the first address of stack memory 10 ;********************************************************************* 11 ;******************* Data Section ********************************* sect ".cinit" ;data, assume start at 0x v_addr.word 0x1234,0x0000,0x3ABC,0x666 ;test vector ABC ;******************************************************************** 16 ;************************ Program ********************************* text ;Program section, assume starts at 0x _c_int00: ;This label tells linker the entry point AD SP,#stack_addr A04 AL,#v_len A9 PUSH AL A0+ AR0,#v_addr A0 PUSH AR ' LC SUB A F00 END1: B END1,UNC 32 ;**************************** Subroutine ************************** a SUB1: a 2AA4 POP AR b 2AA5 POP AR c 2AA0 POP AR d 2AA9 POP AL e 93A0 AH,AR f 95A9 ADD AH,AL BA8 DEC AH A1 AR1,AH FFC0 LSR AL, C0 LOOP: AH,*AR A2 AR2,AH C1 AH,*AR C0 *AR0,AH A2 AH,AR C1 *AR1,AH AA0 INC AR a 0BA1 DEC AR b 0BA9 DEC AL c 60F7 B LOOP,NEQ d 22A5 PUSH AR e 22A4 PUSH AR f 7614 LRET Page 6 Page Score =

EEL 4511 Dr. Gugel LAST NAME FIRST NAME Spring 2016, Real-time DSP Exam #1

EEL 4511 Dr. Gugel LAST NAME FIRST NAME Spring 2016, Real-time DSP Exam #1 Open book and open notes, 60 minute examination, No electronic devices are permitted. Page 1 36 points Page 2 24 points Page 3