user: 下面的汇编指令对应的C源代码是什么:

```asm
<gca_heap_pushdwn>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  push   %r13
  push   %r12
  push   %rbx
  sub    $0x78,%rsp
  mov    %rdi,-0x68(%rbp)
  mov    %rsi,-0x70(%rbp)
  mov    %rdx,-0x78(%rbp)
  mov    %rcx,-0x80(%rbp)
  mov    %r8,-0x88(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x28(%rbp)
  xor    %eax,%eax
  mov    %rsp,%rax
  mov    %rax,%rbx
  mov    -0x78(%rbp),%rax
  mov    %rax,%rdx
  sub    $0x1,%rdx
  mov    %rdx,-0x48(%rbp)
  mov    %rax,%r12
  mov    $0x0,%r13d
  mov    %rax,%r10
  mov    $0x0,%r11d
  mov    $0x10,%edx
  sub    $0x1,%rdx
  add    %rdx,%rax
  mov    $0x10,%edi
  mov    $0x0,%edx
  div    %rdi
  imul   $0x10,%rax,%rax
  mov    %rax,%rcx
  and    $0xfffffffffffff000,%rcx
  mov    %rsp,%rdx
  sub    %rcx,%rdx
L32:
  cmp    %rdx,%rsp
  je     L75
  sub    $0x1000,%rsp
  orq    $0x0,0xff8(%rsp)
  jmp    L32
L75:
  mov    %rax,%rdx
  and    $0xfff,%edx
  sub    %rdx,%rsp
  mov    %rax,%rdx
  and    $0xfff,%edx
  test   %rdx,%rdx
  je     L5
  and    $0xfff,%eax
  sub    $0x8,%rax
  add    %rsp,%rax
  orq    $0x0,(%rax)
L5:
  mov    %rsp,%rax
  add    $0x0,%rax
  mov    %rax,-0x40(%rbp)
  mov    -0x68(%rbp),%rax
  mov    %rax,-0x38(%rbp)
  mov    -0x70(%rbp),%rax
  sub    $0x1,%rax
  imul   -0x78(%rbp),%rax
  mov    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x30(%rbp)
  mov    -0x78(%rbp),%rdx
  mov    -0x30(%rbp),%rcx
  mov    -0x40(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <memcpy@plt>
  mov    -0x38(%rbp),%rax
  mov    %rax,-0x58(%rbp)
  mov    -0x38(%rbp),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x50(%rbp)
  jmp    L64
L77:
  mov    -0x50(%rbp),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  cmp    %rax,-0x30(%rbp)
  jbe    L100
  mov    -0x50(%rbp),%rdx
  mov    -0x78(%rbp),%rax
  lea    (%rdx,%rax,1),%rsi
  mov    -0x88(%rbp),%rdx
  mov    -0x50(%rbp),%rax
  mov    -0x80(%rbp),%rcx
  mov    %rax,%rdi
  call   *%rcx
  test   %eax,%eax
  jns    L100
  mov    -0x50(%rbp),%rdx
  mov    -0x78(%rbp),%rax
  add    %rdx,%rax
  jmp    L59
L100:
  mov    -0x50(%rbp),%rax
L59:
  mov    %rax,-0x50(%rbp)
  mov    -0x88(%rbp),%rdx
  mov    -0x50(%rbp),%rcx
  mov    -0x40(%rbp),%rax
  mov    -0x80(%rbp),%r8
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   *%r8
  test   %eax,%eax
  jns    L33
  mov    -0x78(%rbp),%rdx
  mov    -0x50(%rbp),%rcx
  mov    -0x58(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <memcpy@plt>
  mov    -0x50(%rbp),%rax
  mov    %rax,-0x58(%rbp)
  mov    -0x50(%rbp),%rax
  sub    -0x38(%rbp),%rax
  add    %rax,%rax
  mov    %rax,%rdx
  mov    -0x78(%rbp),%rax
  add    %rax,%rdx
  mov    -0x38(%rbp),%rax
  add    %rdx,%rax
  mov    %rax,-0x50(%rbp)
L64:
  mov    -0x50(%rbp),%rax
  cmp    -0x30(%rbp),%rax
  jb     L77
  jmp    L99
L33:
  nop
L99:
  mov    -0x78(%rbp),%rdx
  mov    -0x40(%rbp),%rcx
  mov    -0x58(%rbp),%rax
  mov    %rcx,%rsi
  mov    %rax,%rdi
  call   <memcpy@plt>
  mov    %rbx,%rsp
  nop
  mov    -0x28(%rbp),%rax
  sub    %fs:0x28,%rax
  je     L13
  call   <__stack_chk_fail@plt>
L13:
  lea    -0x18(%rbp),%rsp
  pop    %rbx
  pop    %r12
  pop    %r13
  pop    %rbp
  ret
```

assistant: ```c
void gca_heap_pushdwn(void *heap, size_t nel, size_t es, int (*compar)(const void *_a, const void *_b, void *_arg), void *arg) {
  char tmp[es], *b = (char *)heap, *last = b + es * (nel - 1), *p, *ch;
  memcpy(tmp, last, es);
  for (p = b, ch = b + es; ch < last; p = ch, ch = b + 2 * (ch - b) + es) {
    ch = (ch + es < last && compar(ch, ch + es, arg) < 0 ? ch + es : ch);
    if (compar(tmp, ch, arg) >= 0)
      break;
    memcpy(p, ch, es);
  }
  memcpy(p, tmp, es);
}
```