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

```asm
<dayno>:
  endbr64
  mov    %edx,%r9d
  movslq %edi,%rdx
  mov    %edi,%eax
  mov    %ecx,%r10d
  imul   $0x51eb851f,%rdx,%rdx
  sar    $0x1f,%eax
  sar    $0x27,%rdx
  sub    %eax,%edx
  imul   $0x190,%edx,%eax
  mov    %edi,%edx
  sub    %eax,%edx
  lea    0x9(%rsi),%eax
  movslq %eax,%rcx
  mov    %eax,%r11d
  lea    0x190(%rdx),%r8d
  imul   $0x2aaaaaab,%rcx,%rcx
  sar    $0x1f,%r11d
  sar    $0x21,%rcx
  sub    %r11d,%ecx
  lea    (%rcx,%rcx,2),%ecx
  shl    $0x2,%ecx
  sub    %ecx,%eax
  add    $0x1,%eax
  imul   $0x1a,%eax,%eax
  sub    $0x2,%eax
  movslq %eax,%rcx
  sar    $0x1f,%eax
  imul   $0x66666667,%rcx,%rcx
  sar    $0x22,%rcx
  sub    %eax,%ecx
  mov    %r8d,%eax
  sar    $0x2,%eax
  lea    0x191(%rdx,%rcx,1),%ecx
  add    %eax,%ecx
  movslq %r8d,%rax
  sar    $0x1f,%r8d
  imul   $0x51eb851f,%rax,%rax
  sar    $0x25,%rax
  sub    %eax,%r8d
  lea    -0x1(%rsi),%eax
  add    %r8d,%ecx
  lea    0x0(,%r9,8),%r8d
  cltq
  sub    %r9d,%r8d
  lea    D6(%rip),%r9
  mov    (%r9,%rax,4),%r9d
  add    %r10d,%r8d
  cmp    $0x2,%esi
  jg     L73
  mov    %edi,%r11d
  and    $0x3,%r11d
  je     L37
L91:
  cmp    $0x1,%edx
  sbb    $0xfffffffa,%ecx
  movslq %ecx,%rax
  mov    %ecx,%r10d
  imul   $0xffffffff92492493,%rax,%rax
  sar    $0x1f,%r10d
  shr    $0x20,%rax
  add    %ecx,%eax
  sar    $0x2,%eax
  sub    %r10d,%eax
  lea    0x0(,%rax,8),%r10d
  sub    %eax,%r10d
  mov    %ecx,%eax
  sub    %r10d,%eax
  cmp    $0x2,%esi
  jne    L77
  test   %r11d,%r11d
  je     L6
L110:
  test   %edx,%edx
  jne    L77
L80:
  add    $0x1,%r9d
  jmp    L77
  nopl   0x0(%rax)
L73:
  movslq %ecx,%rax
  mov    %ecx,%edx
  imul   $0xffffffff92492493,%rax,%rax
  sar    $0x1f,%edx
  shr    $0x20,%rax
  add    %ecx,%eax
  sar    $0x2,%eax
  sub    %edx,%eax
  lea    0x0(,%rax,8),%edx
  sub    %eax,%edx
  mov    %ecx,%eax
  sub    %edx,%eax
L77:
  xor    %r10d,%r10d
  cmp    %r8d,%eax
  jg     L89
  sub    %eax,%r8d
  lea    0x1(%r8),%eax
  cmp    %r9d,%r8d
  cmovl  %eax,%r10d
L89:
  mov    %r10d,%eax
  ret
  nopl   0x0(%rax)
L37:
  imul   $0xc28f5c29,%edi,%eax
  add    $0x51eb850,%eax
  ror    $0x2,%eax
  cmp    $0x28f5c28,%eax
  jbe    L91
  add    $0x5,%ecx
  movslq %ecx,%rax
  mov    %ecx,%edx
  imul   $0xffffffff92492493,%rax,%rax
  sar    $0x1f,%edx
  shr    $0x20,%rax
  add    %ecx,%eax
  sar    $0x2,%eax
  sub    %edx,%eax
  lea    0x0(,%rax,8),%edx
  sub    %eax,%edx
  mov    %ecx,%eax
  sub    %edx,%eax
  cmp    $0x2,%esi
  je     L80
  jmp    L77
  xchg   %ax,%ax
L6:
  imul   $0xc28f5c29,%edi,%edi
  add    $0x51eb850,%edi
  ror    $0x2,%edi
  cmp    $0x28f5c28,%edi
  jbe    L110
  jmp    L80
```

tool_calls: name: parse_data
arguments: data_label: D6
type: string

tool: D6: 

assistant: ```c
int dayno(int yyyy, int mm, int x, int y) {
  static int daytab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
  int a, b, c;
  a = ((((((mm) + 9) % 12 + 1) * 26 - 2) / 10 + (1) + ((yyyy) % 400 + 400) + ((yyyy) % 400 + 400) / 4 - ((yyyy) % 400 + 400) / 100 + (((mm) <= 2) ? ((((((yyyy) % 4) == 0) && (((yyyy) % 100) != 0)) || (((yyyy) % 400) == 0)) ? 5 : 6) : 0)) % 7);
  b = x * 7 + y;
  c = daytab[mm - 1];
  if ((mm == 2) && ((((yyyy % 4) == 0) && ((yyyy % 100) != 0)) || ((yyyy % 400) == 0)))
    c++;
  if (b < a)
    return (0);
  if ((b - a) >= c)
    return (0);
  return ((b - a + 1));
}
```