user: What would the C source look like for the assembly code provided here:

```asm
<Day>:
  endbr64
  push   %r15
  push   %r14
  mov    %edx,%r14d
  push   %r13
  push   %r12
  mov    %esi,%r12d
  push   %rbp
  mov    %edi,%ebp
  push   %rbx
  sub    $0x48,%rsp
  mov    %fs:0x28,%rax
  mov    %rax,0x38(%rsp)
  movabs $0x1c0000001f,%rax
  mov    %rax,(%rsp)
  movabs $0x1e0000001f,%rax
  mov    %rax,0x8(%rsp)
  mov    %rax,0x10(%rsp)
  movabs $0x1f0000001f,%rax
  mov    %rax,0x18(%rsp)
  sub    $0x1,%rax
  mov    %rax,0x20(%rsp)
  mov    %rax,0x28(%rsp)
  call   <Leap@plt>
  mov    %eax,%r13d
  lea    -0x1(%rbp),%eax
  cmp    $0x270e,%eax
  ja     L0
  lea    -0x1(%r12),%eax
  cmp    $0xb,%eax
  ja     L174
  cmp    $0x2,%r12d
  je     L70
  cltq
  cmp    %r14d,(%rsp,%rax,4)
  jl     L146
L87:
  test   %r14d,%r14d
  jle    L146
  mov    $0x1,%ebx
  cmp    $0x1,%ebp
  je     L90
  mov    $0x1,%r15d
  jmp    L58
  nopl   0x0(%rax)
L209:
  lea    0x16e(%rbx),%eax
L156:
  movslq %eax,%rbx
  cltd
  add    $0x1,%r15d
  imul   $0xffffffff92492493,%rbx,%rbx
  shr    $0x20,%rbx
  add    %eax,%ebx
  sar    $0x2,%ebx
  sub    %edx,%ebx
  lea    0x0(,%rbx,8),%edx
  sub    %ebx,%edx
  sub    %edx,%eax
  mov    %eax,%ebx
  cmp    %r15d,%ebp
  je     L90
L58:
  mov    %r15d,%edi
  call   <Leap@plt>
  test   %eax,%eax
  jne    L209
  lea    0x16d(%rbx),%eax
  jmp    L156
  cs nopw 0x0(%rax,%rax,1)
L90:
  cmp    $0x1,%r12d
  je     L1
  mov    $0x1,%ecx
  mov    $0x1,%eax
  jmp    L97
  nopw   0x0(%rax,%rax,1)
L33:
  lea    0x1f(%rbx),%edx
  cmp    $0x2,%ecx
  je     L142
L98:
  movslq %edx,%rbx
  mov    %edx,%esi
  add    $0x1,%ecx
  imul   $0xffffffff92492493,%rbx,%rbx
  sar    $0x1f,%esi
  shr    $0x20,%rbx
  add    %edx,%ebx
  sar    $0x2,%ebx
  sub    %esi,%ebx
  lea    0x0(,%rbx,8),%esi
  sub    %ebx,%esi
  sub    %esi,%edx
  mov    %edx,%ebx
  cmp    %ecx,%r12d
  je     L1
L97:
  mov    %rax,%rdx
  shl    %cl,%rdx
  test   $0xa50,%edx
  je     L33
  lea    0x1e(%rbx),%edx
  jmp    L98
  nopw   0x0(%rax,%rax,1)
L142:
  lea    0x1d(%rbx),%edx
  test   %r13d,%r13d
  jne    L98
  lea    0x1c(%rbx),%edx
  jmp    L98
  nopl   (%rax)
L1:
  lea    -0x1(%rbx,%r14,1),%edx
  movslq %edx,%rax
  mov    %edx,%ecx
  imul   $0xffffffff92492493,%rax,%rax
  sar    $0x1f,%ecx
  shr    $0x20,%rax
  add    %edx,%eax
  sar    $0x2,%eax
  sub    %ecx,%eax
  lea    0x0(,%rax,8),%ecx
  sub    %eax,%ecx
  mov    %edx,%eax
  sub    %ecx,%eax
L14:
  mov    0x38(%rsp),%rdx
  sub    %fs:0x28,%rdx
  jne    L62
  add    $0x48,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L70:
  lea    0x1c(%r13),%eax
  cmp    %r14d,%eax
  jge    L87
L146:
  mov    $0xfffffffd,%eax
  jmp    L14
L174:
  mov    $0xfffffffe,%eax
  jmp    L14
L0:
  mov    $0xffffffff,%eax
  jmp    L14
L62:
  call   <__stack_chk_fail@plt>
```

assistant: ```c
int Day(int y, int m, int d) {
  int day_tab[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  int k = Leap(y);
  if (y <= 0 || y > 9999)
    return -1;
  else if (m > 12 || m <= 0)
    return -2;
  else if (m == 2 && d > day_tab[m - 1] + k)
    return -3;
  else if ((d > day_tab[m - 1] && m != 2) || d <= 0)
    return -3;
  int i = 0, n = 1;
  for (i = 1; i < y; i++) {
    if (Leap(i))
      n = (n + 366) % 7;
    else
      n = (n + 365) % 7;
  }
  for (i = 1; i < m; i++) {
    switch (i) {
    case 2:
      if (k) {
        n = (n + 29) % 7;
      } else {
        n = (n + 28) % 7;
      }
      break;
    case 4:
    case 6:
    case 9:
    case 11:
      n = (n + 30) % 7;
      break;
    default:
      n = (n + 31) % 7;
    }
  }
  n = (n + d - 1) % 7;
  return n;
}
```