The process register state and flags

The user_regs_struct structure for x86_64 contains the general-purpose registers, segmentation registers, stack pointer, instruction pointer, CPU flags, and TLS registers:

<sys/user.h>
struct user_regs_struct
{
  __extension__ unsigned long long int r15;
  __extension__ unsigned long long int r14;
  __extension__ unsigned long long int r13;
  __extension__ unsigned long long int r12;
  __extension__ unsigned long long int rbp;
  __extension__ unsigned long long int rbx;
  __extension__ unsigned long long int r11;
  __extension__ unsigned long long int r10;
  __extension__ unsigned long long int r9;
  __extension__ unsigned long long int r8;
  __extension__ unsigned long long int rax;
  __extension__ unsigned long long int rcx;
  __extension__ unsigned long long int rdx;
  __extension__ unsigned long long int rsi;
  __extension__ unsigned long long int rdi;
  __extension__ unsigned long long int orig_rax;
  __extension__ unsigned long long int rip...