user: What is the c source code of the assembly code below?

```asm
<candidates>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x60,%rsp
  mov    %rdi,-0x58(%rbp)
  mov    %esi,-0x5c(%rbp)
  mov    %fs:0x28,%rax
  mov    %rax,-0x8(%rbp)
  xor    %eax,%eax
  movl   $0x3,-0x44(%rbp)
  mov    -0x5c(%rbp),%eax
  movslq %eax,%rdx
  imul   $0x38e38e39,%rdx,%rdx
  shr    $0x20,%rdx
  sar    %edx
  mov    %eax,%esi
  sar    $0x1f,%esi
  mov    %edx,%ecx
  sub    %esi,%ecx
  mov    %ecx,%edx
  shl    $0x3,%edx
  add    %ecx,%edx
  sub    %edx,%eax
  mov    %eax,-0x40(%rbp)
  mov    -0x5c(%rbp),%eax
  movslq %eax,%rdx
  imul   $0x38e38e39,%rdx,%rdx
  shr    $0x20,%rdx
  sar    %edx
  sar    $0x1f,%eax
  mov    %eax,%ecx
  mov    %edx,%eax
  sub    %ecx,%eax
  mov    %eax,-0x3c(%rbp)
  mov    -0x40(%rbp),%eax
  cltd
  idivl  -0x44(%rbp)
  mov    -0x40(%rbp),%eax
  sub    %edx,%eax
  mov    %eax,-0x38(%rbp)
  mov    -0x3c(%rbp),%eax
  cltd
  idivl  -0x44(%rbp)
  mov    -0x3c(%rbp),%eax
  sub    %edx,%eax
  mov    %eax,-0x34(%rbp)
  movq   $0x0,-0x30(%rbp)
  movq   $0x0,-0x28(%rbp)
  movq   $0x0,-0x20(%rbp)
  movq   $0x0,-0x18(%rbp)
  movq   $0x0,-0x10(%rbp)
  movl   $0x0,-0x48(%rbp)
  movl   $0x0,-0x4c(%rbp)
  jmp    L51
L41:
  mov    -0x3c(%rbp),%edx
  mov    -0x4c(%rbp),%ecx
  mov    -0x58(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <getAt@plt>
  mov    -0x30(%rbp,%rax,4),%edx
  add    $0x1,%edx
  mov    %edx,-0x30(%rbp,%rax,4)
  mov    -0x4c(%rbp),%edx
  mov    -0x40(%rbp),%ecx
  mov    -0x58(%rbp),%rax
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <getAt@plt>
  mov    -0x30(%rbp,%rax,4),%edx
  add    $0x1,%edx
  mov    %edx,-0x30(%rbp,%rax,4)
  mov    -0x4c(%rbp),%eax
  cltd
  idivl  -0x44(%rbp)
  mov    %eax,%edx
  mov    -0x34(%rbp),%eax
  lea    (%rdx,%rax,1),%esi
  mov    -0x4c(%rbp),%eax
  cltd
  idivl  -0x44(%rbp)
  mov    -0x38(%rbp),%eax
  lea    (%rdx,%rax,1),%ecx
  mov    -0x58(%rbp),%rax
  mov    %esi,%edx
  mov    %ecx,%esi
  mov    %rax,%rdi
  call   <getAt@plt>
  mov    -0x30(%rbp,%rax,4),%edx
  add    $0x1,%edx
  mov    %edx,-0x30(%rbp,%rax,4)
  addl   $0x1,-0x4c(%rbp)
L51:
  cmpl   $0x8,-0x4c(%rbp)
  jle    L41
  movl   $0x1,-0x4c(%rbp)
  jmp    L47
L37:
  mov    -0x4c(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  lea    -0x30(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  test   %eax,%eax
  jne    L13
  cmpl   $0x0,-0x48(%rbp)
  jle    L4
  mov    $0x0,%eax
  jmp    L75
L4:
  mov    -0x4c(%rbp),%eax
  mov    %eax,-0x48(%rbp)
L13:
  addl   $0x1,-0x4c(%rbp)
L47:
  cmpl   $0x9,-0x4c(%rbp)
  jle    L37
  mov    -0x5c(%rbp),%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x58(%rbp),%rax
  add    %rax,%rdx
  mov    -0x48(%rbp),%eax
  mov    %eax,(%rdx)
  cmpl   $0x0,-0x48(%rbp)
  setg   %al
  movzbl %al,%eax
L75:
  mov    -0x8(%rbp),%rdx
  sub    %fs:0x28,%rdx
  je     L63
  call   <__stack_chk_fail@plt>
L63:
  leave
  ret
```

assistant: ```c
int candidates(int *grid, int index) {
  int boxN = 9 / 3;
  int x = index % 9;
  int y = index / 9;
  int boxX = x - (x % boxN);
  int boxY = y - (y % boxN);
  int i;
  int counts[9 + 1] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
  int candidate = 0;
  for (i = 0; i < 9; i++) {
    counts[getAt(grid, i, y)]++;
    counts[getAt(grid, x, i)]++;
    counts[getAt(grid, boxX + (int)(i % boxN), boxY + (int)(i / boxN))]++;
  }
  for (i = 1; i <= 9; i++) {
    if (*(counts + i) == 0) {
      if (candidate > 0) {
        return 0;
      }
      candidate = i;
    }
  }
  grid[index] = candidate;
  return candidate > 0;
}
```