Question

Match each of the assembler routines with the equivalent C functions. Note: shrq is the logical right shift instruction,
and sarq is the arithmetic right shift instruction.

Question 3 options:

foo5: leaq -4(%rdi), %rax shrq $63, %rax ret

foo2: movq %rdi, %rax salq $4, %rax ret

foo3: movq %rdi, %rax sarq $4, %rax ret

foo4: leaq 4(%rdi), %rax ret

foo1: leaq 0(,%rdi,4), %rax ret

1. long choice1(long x) { return x - 4 < 0; } 2. long choice2(long x) { return 4*x; } 3. long choice3(long x) { return x>>4; } 4. long choice4(long x) { return x*16; } 5. long choice5(long x) { return x+4; } 6. long choice6(long x) { return x+8; }

Answer 1

1-1 [foo5 - choice1] because leaq will add -4 to x and shrq will check <0

2-4[foo2 -choice4] 4 time left shift means multiply by 16

3-3[foo3-choice3] right shift

4-5 [foo4-choice5] leaq will add 4 to x

5-2 [foo1-choice2] leaq will add as 0 + 4*x

PLEASE UPVOTE