CSC 371 - Systems I: Computer Organization and Architecture

Dr. R. M. Siegfried

Assignment 10 - p. 235-236(handout)/7-5. 7-14, 7-15

Due Friday, December 8, 2017

7-5

The system shown in figure 7-2 (of the textbook; see slide 10 of Lecture 10) uses a control memory of 1024 words of 32 bits each. The microinstruction has three fields as shown in that diagram. The microoperations fields has 16 bits.

  1. How many bits are there in the branch address field and the select field?
  2. If there are 16 status bits in the system, how many bits of the branch logic are used to select a status bit
  3. How many bits are left to select an input fo the multiplexers?

7-14

The following is a symbolic microprogram for an instruction in the computer defined in section 7-3 (slides 16-27 in Lecture 10). 

        ORG 40
    	NOP 	S	JMP	FETCH
    	NOP 	Z	JMP	FETCH
    	NOP 	I	CALL	INDRCT
	ARTPC	U	JMP	FETCH

  1. Specify the operation performed when the instruction is executed
  2. Convert the four microoperations into their equivalent binary form

7-15

The computer of Sec. 7-3 has the following binary microprogram:


Address				Binary Microprogram
   60		0  1  0  0  0  0  0  1  0  0  0  0  0  1  0  0  0  0  1  1
   61		1  1  1  1  0  0  0  0  0  0  1  0  1  1  0  0  0  0  0  0
   62		0  0  1  0  0  1  0  0  0  1  0  1  0  0  1  1  1  1  1  1
   63		1  0  1  1  1  0  0  0  0  1  1  1  1  0  1  1  1  1  0  0
  1. Translate it to a symbolic microporgram as in Table 7-2 ( FETCH is in address 64 and INDRCT in address 67.)
  2. LIst all the things that will be wrong when this microprogram is executed in the computer.

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