Question

A C function fun has the following code body: *p = d; return x-c; The IA32 code implementing this body is as follows: movsbl 12(%ebp), %edx movl 16(%ebp), %eax movl %edx, (%eax) movswl 8(%ebp), %eax movl 20(%ebp), %edx subl %eax, %edx movl %edx, %eax Write a prototype for function fun, showing the types and ordering of the arguments p, d, x, and c.

          A C function fun has the following code body:
*p = d;
return x-c;
The IA32 code implementing this body is as follows:
movsbl 12(%ebp), %edx
movl 16(%ebp), %eax
movl %edx, (%eax)
movswl 8(%ebp), %eax
movl 20(%ebp), %edx
subl %eax, %edx
movl %edx, %eax
Write a prototype for function fun, showing the types and ordering of the
arguments p, d, x, and c.

A C function fun has the following code body:
*p = d;
return x-c;
The IA32 code implementing this body is as follows:
movsbl 12(%ebp), %edx
movl 16(%ebp), %eax
movl %edx, (%eax)
movswl 8(%ebp), %eax
movl 20(%ebp), %edx
subl %eax, %edx
movl %edx, %eax
Write a prototype for function fun, showing the types and ordering of the
arguments p, d, x, and c.

Added by Ricardo S.

Computer Science and Information Technology

Trishna Knowledge Systems 2018 Edition

Instant Answer

Solved by Expert Corbin Tegner

Step 1

movsbl 12(%ebp), %edx - This instruction moves the signed byte value at the memory location 12(%ebp) into the %edx register. This suggests that the argument 'd' is a signed byte value. Show more…

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A C function fun has the following code body: *p = d; return x - c; The IA32 code implementing this body is as follows: 1. movsbl 12(%ebp), %edx 2. movl 16(%ebp), %eax 3. movl %edx, %eax 4. movswl 8(%ebp), %eax 5. movl 20(%ebp), %edx 6. subl %eax, %edx 7. movl %edx, %eax Write a prototype for function fun, showing the types and ordering of the arguments p, d, x, and c.