user: 下面的汇编指令对应的C源代码是什么:

```asm
<substr_combine>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x38,%rsp
  mov    %rdi,-0x58(%rbp)
  mov    %rsi,%rbx
  mov    %edx,%r15d
  mov    %edx,-0x44(%rbp)
  mov    %rcx,-0x50(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x38(%rbp)
  xor    %eax,%eax
  lea    D59(%rip),%rdi
  call   <puts@plt>
  test   %r15d,%r15d
  je     L83
  mov    %rbx,%r14
  lea    -0x1(%r15),%eax
  lea    0x4(%rbx,%rax,4),%r15
  mov    $0x0,%r12d
  lea    D12(%rip),%r13
L97:
  mov    (%rbx),%edi
  call   <substr_len@plt>
  add    %rax,%r12
  mov    %r12,%rsi
  mov    %r13,%rdi
  mov    $0x0,%eax
  call   <printf@plt>
  add    $0x4,%rbx
  cmp    %r15,%rbx
  jne    L97
  lea    D44(%rip),%rdi
  call   <puts@plt>
  cmp    %r12,-0x50(%rbp)
  jbe    L67
  movl   $0x0,-0x44(%rbp)
  jmp    L70
L67:
  lea    D64(%rip),%rdi
  call   <puts@plt>
  mov    $0xffffffff,%eax
  jmp    L15
L3:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  test   %rdx,%rdx
  je     L59
  orq    $0x0,-0x8(%rsp,%rdx,1)
L59:
  mov    %ebx,%edx
  mov    %r13d,%esi
  mov    %rsp,%rdi
  call   <substr_assemble@plt>
  mov    -0x44(%rbp),%edi
  add    -0x58(%rbp),%rdi
  mov    %ebx,%edx
  mov    %rsp,%rsi
  call   <strcpy_limit@plt>
  add    %eax,-0x44(%rbp)
  mov    -0x44(%rbp),%esi
  mov    %ebx,%ecx
  mov    %r13d,%edx
  lea    D60(%rip),%rdi
  mov    $0x0,%eax
  call   <printf@plt>
  mov    -0x50(%rbp),%rsp
  add    $0x4,%r14
  cmp    %r15,%r14
  je     L55
L70:
  mov    %rsp,-0x50(%rbp)
  mov    (%r14),%r13d
  mov    %r13d,%edi
  call   <substr_size@plt>
  mov    %eax,%ebx
  mov    %eax,%eax
  add    $0xf,%rax
  shr    $0x4,%rax
  shl    $0x4,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L16:
  cmp    %rdx,%rsp
  je     L3
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L16
L83:
  lea    D44(%rip),%rdi
  call   <puts@plt>
  cmpq   $0x0,-0x50(%rbp)
  je     L67
  mov    $0x0,%r12d
L55:
  lea    D4(%rip),%rdi
  call   <puts@plt>
  mov    -0x58(%rbp),%rax
  movb   $0x0,(%rax,%r12,1)
  mov    -0x44(%rbp),%eax
L15:
  mov    -0x38(%rbp),%rdx
  sub    %fs:0x28,%rdx
  jne    L13
  lea    -0x28(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  pop    %rbp
  ret
L13:
  call   <__stack_chk_fail@plt>
```

tool_calls: name: unpack_data
arguments: tag: D59
type: string
name: unpack_data
arguments: tag: D12
type: string
name: unpack_data
arguments: tag: D44
type: string
name: unpack_data
arguments: tag: D64
type: string
name: unpack_data
arguments: tag: D60
type: string
name: unpack_data
arguments: tag: D4
type: string

tool: D59: 1111

tool: D12: total_len %d


tool: D44: 22222

tool: D64: 33333

tool: D60: offs %d, id%d, max %d


tool: D4: 44444

assistant: ```c
int substr_combine(char *dst, int *substr_ids, unsigned int n_ints, size_t dst_sz) {
  printf("1111\n");
  unsigned int i = 0;
  size_t total_len = 0;
  for (i = 0; i < n_ints; ++i) {
    total_len += substr_len(substr_ids[i]);
    printf("total_len %d\n", total_len);
  }
  printf("22222\n");
  if (total_len >= dst_sz) {
    printf("33333\n");
    return -1;
  }
  unsigned int offs = 0;
  unsigned int max = 0;
  for (i = 0; i < n_ints; ++i) {
    int id = substr_ids[i];
    max = substr_size(id);
    char src[max];
    substr_assemble(src, id, max);
    offs += strcpy_limit(&dst[offs], src, max);
    printf("offs %d, id%d, max %d\n", offs, id, max);
  }
  printf("44444\n");
  dst[total_len] = '\0';
  return offs;
}
```