One of the autors, who wishes to remain anonymous, initially encoded fields F6 a

Question

One of the autors, who wishes to remain anonymous, initially encoded fields F6 and F7 of Table 5.6 in a single field.

a. Give two reasons why this is an error.

b. Why is he sure that all three operations can be grouped together in F7?

Table. 5.6

Table 5.6 Somewhat Vertical Encoding of the SRC Microinstruction F1 F2 F7 F8 F9 F6 F5 F3 F4 Gate Registers ALU Branch Out In | Signals | Misc. ISc. | Control | End | Signals 2 Control End Signals 00 Gra 01 Grb 10 Gre 11 None 0000 ADD 10 0001 C=B | bits 0010 SHR 00 | 000Un_ | 0 Cont. | 000 PCout 01 001 CON | 1 End | 001 c.,u 1 000 MAin 001 PC | 000 Read 001 Write 1 01 001 CON 1 End 001 Cou 10 010 CON 11 1011n=0 010 MDout010 IR 010 Wait 01 1R ut 0011 INC4 01 IR 100 BAout 100 Rin 100 CONn 101 clout 110 c2out 111 None 111 None 111 None 011 Ain Ai 011 Decr 100 n 0 101 None 10I MDi101 Cin 101 M110 Stop t110Ld 110 Ld 1111 NOT bits bits 4 bits 10 bits bit bits bits bits bits was bumned out cre

Explanation / Answer

a)
In a control sequence for the 1-bus SRC,grc occours simultaneous;y with Cin in add simultaneously with Ld in shr and simultaneously with CONin in br.Grb occurs simultaneously with Cm in shr.thus the simultaneously G signals must be specified in a seperate field from the others

b)
It is guaranteed that 2G signals cannnot occur in the smae step because there is only one 5 to 32 decoder in the register file design for 1-bus SRC.Thus only one of the ra,rb,and rc fields can be ated to it a time

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.