** program './hello' loaded. entry point 0x401000.
    401000: f3 0f 1e fa                         endbr64		
    401004: 55                                  push		rbp
    401005: 48 89 e5                            mov		rbp, rsp
    401008: ba 0e 00 00 00                      mov		edx, 0xe
    40100d: 48 8d 05 ec 0f 00 00                lea		rax, [rip + 0xfec]
(sdb) break 0x401030
** set a breakpoint at 0x401030.
(sdb) break 0x401040
** set a breakpoint at 0x401040.
(sdb) syscall
** hit a breakpoint at 0x401030.
    401030: 0f 05                               syscall		
    401032: c3                                  ret		
    401033: b8 00 00 00 00                      mov		eax, 0
    401038: 0f 05                               syscall		
    40103a: c3                                  ret		
(sdb) syscall
** enter a syscall(1) at 0x401030.
    401030: 0f 05                               syscall		
    401032: c3                                  ret		
    401033: b8 00 00 00 00                      mov		eax, 0
    401038: 0f 05                               syscall		
    40103a: c3                                  ret		
(sdb) cont
hello world!
** hit a breakpoint at 0x401040.
    401040: 0f 05                               syscall		
** the address is out of the range of the text section.
(sdb) syscall
** enter a syscall(60) at 0x401040.
    401040: 0f 05                               syscall		
** the address is out of the range of the text section.
(sdb) syscall
** the target program terminated.