1

2 //Assembly code takes the return addr off the stack and saves

3 // into the singleton. The first field in the singleton is the

4 // "endInstrAddr" field, and the return addr is at 0x4(%ebp)

5 .globl asm_save_ret_to_singleton

6 asm_save_ret_to_singleton:

7 movq 0x8(%rbp), %rax #get ret address, ebp is the same as in the calling function

8 movq %rax, (%rdi) #write ret addr to endInstrAddr field

9 ret

10

11

12 //Assembly code changes the return addr on the stack to the one

13 // saved into the singleton by the end-singleton-fn

14 //The stack's return addr is at 0x4(%%ebp)

15 .globl asm_write_ret_from_singleton

16 asm_write_ret_from_singleton:

17 movq (%rdi), %rax #get endInstrAddr field

18 movq %rax, 0x8(%rbp) #write return addr to the stack of the caller

19 ret

20

21