Exercise 2.12 In the following problems, the data table contains various modifi cations that could be made to the MIPS instruction set architecture. You will investigate the impact of these changes on the instruction format of the MIPS architecture.

a. 8 registers

b. 10 bit immediate constants 2.12.1 [5] <2.5> If the instruction set of the MIPS processor is modifi ed, the instruction format must also be changed. For each of the suggested changes above, show the size of the bit fi elds of an R-type format instruction. What is the total number of bits needed for each instruction?

2.12.2 [5] <2.5> If the instruction set of the MIPS processor is modifi ed, the instruction format must also be changed. For each of the suggested changes above, show the size of the bit fi elds of an I-type format instruction. What is the total number of bits needed for each instruction?

2.12.3 [5] <2.5, 2.10> Why could the suggested change in the table above decrease the size of a MIPS assembly program? Why could the suggested change in the table above increase the size of a MIPS assembly program?

In the following problems, the data table contains hexadecimal values. You will be asked to determine what MIPS instruction the value represents, and fi nd the MIPS instruction format.

a. 0x01090010

b. 0x8D090012 2.12.4 [5] <2.5> For the entries above, what is the value of the number in decimal?

2.12.5 [5] <2.5> For the hexadecimal entries above, what instruction do they represent?
2.12.6 [5] <2.4, 2.5> What type (I-type, R-type) instruction do the binary entries above represent? What is the value of the op fi eld and the rt fi eld?