Exercise 2.4 The following problems deal with translating from C to MIPS. Assume that the variables

f, g, h, i, and j are assigned to registers $s0, $s1, $s2, $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

a. f = g + h + B[4];

b. f = g – A[B[4]];

2.4.1 [10] <2.2, 2.3> For the C statements above, what is the corresponding MIPS assembly code?

2.4.2 [5] <2.2, 2.3> For the C statements above, how many MIPS assembly instructions are needed to perform the C statement?

2.4.3 [5] <2.2, 2.3> For the C statements above, how many different registers are needed to carry out the C statement?

The following problems deal with translating from MIPS to C. Assume that the variables

f, g, h, i, and j are assigned to registers $s0, $s1, $s2, $s3, and $s4, respectively. Assume that the base address of the arrays A and B are in registers $s6 and $s7, respectively.

a. add $s0, $s0, $s1 add $s0, $s0, $s2 add $s0, $s0, $s3 add $s0, $s0, $s4

b. lw $s0, 4($s6)
2.4.4 [10] <2.2, 2.3> For the MIPS assembly instructions above, what is the corresponding C statement?
2.4.5 [5] <2.2, 2.3> For the MIPS assembly instructions above, rewrite the assembly code to minimize the number of MIPS instructions (if possible) needed to carry out the same function.
2.4.6 [5] <2.2, 2.3> How many registers are needed to carry out the MIPS assembly as written above? If you could rewrite the code above, what is the minimal number of registers needed?