ZuoTi.Pro
Question

The following code sequence occurs near the beginning of the assembly code generated by gcc for a c procedure: 9. 1, subq 2 movq 3 movq 4 movq 5. movq 6. movq 7. movq 8. movq 9. movq 10. movq $24,%rsp %rbx, (%rsp) %r12, 8(%rsp) %r13, 16(%rsp) 16(%rbp), %rbx 24(%rbp), %r13 (%rbx), %r12 (%r13), %rax 16(%rbp ) ,%rdx (%rdx), %rcx we see that just three registers (%rbx, %r12 and %r13) are saved on the stack in lines 2-4. The program modifies these and others. At the end of the procedure, the values of the registers %rbx, %r12, and %r13 are restored (those instructions are not shown) while the other registers are left in their modified states. Why are not all of the registers saved and restored?

May you explain how you got the answer

engineering   Computer-Science   
0 0
Add a comment Improve this question Transcribed image text
Next > < Previous
Sort answers by oldest

Homework Answers

Answer #1

-Answer -At ae kneuw a precenov eskoeo a small sel o dato holplaces Kat- tre Part ob -the computer procesor ster mau hold an nsctfon , a ok, or an suoh a a rh. and Ri are contéJeredl nonyo lale and muct be saved and yestosedbandion thart cuser them because these belonthallAq fRinction m3 belong t the Colleng function and the called Aunetons other oods, a called mus rererve there to the called fanction and a calfunton Call, mt cave the valuenocal stack ne

0 0
Add a comment
Know the answer?
Add Answer to:
May you explain how you got the answer The following code sequence occurs near the beginning...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions

  • Write the C Code for the Intel assembley below. Note: Don't copy and paste anything from...

    Write the C Code for the Intel assembley below. Note: Don't copy and paste anything from github because it won't be the right answer. .file "mystery.c" .comm num,1600,32 .text .globl add .type add, @function add: .LFB2: .cfi_startproc pushq %rbp .cfi_def_cfa_offset 16 .cfi_offset 6, -16 movq %rsp, %rbp .cfi_def_cfa_register 6 movq %rdi, -8(%rbp) movq %rsi, -16(%rbp) movq -16(%rbp), %rax movq -8(%rbp), %rdx addq %rdx, %rax popq %rbp .cfi_def_cfa 7, 8 ret .cfi_endproc .LFE2: .size add, .-add .globl dothething .type dothething, @function...

  • You know the following assembly code snippet is from a recursive function in C. You also...

    You know the following assembly code snippet is from a recursive function in C. You also know that the stack contents at a particular point in time when we are in the recursive function are shown on the next page. Answer the following questions: a) how many Foo stack frames are on the stack? b) what is the return address back to the function that called Foo for the first time? c) what is the return address back into the...

  • a) Write the following C function in Assembly. You must follow the System V 64-bit calling...

    a) Write the following C function in Assembly. You must follow the System V 64-bit calling convention and use AT&T Syntax notation. long fibonacci (long n) { if (n == 0) return 0; else if (n == 1) return 1; else return (fibonacci (n - 1) + fibonacci (n - 2)); } b) The Windows x86-64 calling convention passes function parameters in the registers RCX, RDX, R8 and R9 and returns values on register RAX. Caller saved registers are: RAX,...

  • a) Write the following C function in Assembly. You must follow the System V 64-bit calling convention and use AT&T S...

    a) Write the following C function in Assembly. You must follow the System V 64-bit calling convention and use AT&T Syntax notation. Note: You cannot change the algorithm in any way so your assembly function must still be recursive. (20 points) long Catalan(long n) { long sum = 0; if (n == 0) return 1; for (int i = 0; i < n; i++) { sum += Catalan(i) * Catalan(n - i - 1); } return sum; } b) The...

  • Assembly language 64 bit please ! An example file for set up ==========+ ;| Data Segment...

    Assembly language 64 bit please ! An example file for set up ==========+ ;| Data Segment BEGINS Here | ;+======================================================================+ segment .data ;Code this expression: sum = num1+num2 num1 dq 0 ;left operand of the addition operation num2 dq 0 ;right operand of the addition operation sum dq 0 ;will hold the computed Sum value RetVal dq 0 ;Integer value RETURNED by function calls ;can be ignored or used as determined by the programmer ;Message string prompting for the keyboard...

  • Consider the following source code, where b, c, and d are constants declared with #define. You...

    Consider the following source code, where b, c, and d are constants declared with #define. You will need to determine the values for b, c, and d. struct lnode { char *str; struct lnode *next; } struct lnode A[b][c][d]; int store_ele(int h, int i, int j, struct lnode dest) { A[h][i][j] = dest; return sizeof(A);} On compiling this program (with -O2), GCC generates the following assembly code for the store_ele function: store_ele: movslq %edi, %rdi movslq %esi, %rsi movslq %edx,...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT