user: Converte this assembly snippet into its equivalent C code:

```asm
<conf>:
  endbr64
  push   %r15
  mov    %edi,%eax
  push   %r14
  sar    $0x1f,%eax
  lea    -0x1(%rsi),%r14d
  push   %r13
  mov    %rdx,%r13
  push   %r12
  mov    %esi,%r12d
  push   %rbp
  push   %rbx
  movslq %edi,%rbx
  imul   $0x66666667,%rbx,%rbx
  sub    $0x18,%rsp
  sar    $0x22,%rbx
  sub    %eax,%ebx
  lea    (%rbx,%rbx,4),%eax
  add    %eax,%eax
  sub    %eax,%edi
  lea    0x30(%rdi),%ebp
  test   %esi,%esi
  je     L93
  movslq %r14d,%r15
  mov    %r14d,%eax
  mov    $0x20,%esi
  mov    %r15,%rdi
  lea    0x1(%rax),%rdx
  sub    %rax,%rdi
  add    %r13,%rdi
  call   <memset@plt>
  test   %ebx,%ebx
  jne    L149
L60:
  mov    %bpl,0x0(%r13,%r15,1)
  add    $0x18,%rsp
  mov    %r12d,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax,%rax,1)
L149:
  lea    -0x2(%r12),%ecx
  test   %r14d,%r14d
  je     L69
  movslq %ecx,%r14
  mov    %ecx,%eax
  mov    $0x20,%esi
  mov    %ecx,0x8(%rsp)
  mov    %r14,%rdi
  lea    0x1(%rax),%rdx
  sub    %rax,%rdi
  add    %r13,%rdi
  call   <memset@plt>
  movslq %ebx,%rax
  mov    %ebx,%edx
  mov    0x8(%rsp),%ecx
  imul   $0x66666667,%rax,%rax
  sar    $0x1f,%edx
  sar    $0x22,%rax
  sub    %edx,%eax
  lea    (%rax,%rax,4),%edx
  add    %edx,%edx
  sub    %edx,%ebx
  test   %eax,%eax
  lea    0x30(%rbx),%r8d
  mov    %eax,%ebx
  jne    L126
L104:
  mov    %r8b,0x0(%r13,%r14,1)
  jmp    L60
L126:
  lea    -0x3(%r12),%r9d
  test   %ecx,%ecx
  je     L155
L102:
  mov    %r9d,%eax
  movslq %r9d,%rdi
  mov    $0x20,%esi
  mov    %r8b,0xf(%rsp)
  sub    %rax,%rdi
  lea    0x1(%rax),%rdx
  mov    %r9d,0x8(%rsp)
  add    %r13,%rdi
  call   <memset@plt>
  movzbl 0xf(%rsp),%r8d
  mov    0x8(%rsp),%r9d
L155:
  movslq %ebx,%rdi
  mov    %ebx,%eax
  imul   $0x66666667,%rdi,%rdi
  sar    $0x1f,%eax
  sar    $0x22,%rdi
  sub    %eax,%edi
  mov    %ebx,%eax
  lea    (%rdi,%rdi,4),%edx
  add    %edx,%edx
  sub    %edx,%eax
  lea    0x30(%rax),%ebx
  movslq %r9d,%rax
  test   %edi,%edi
  jne    L41
L87:
  mov    %bl,0x0(%r13,%rax,1)
  mov    %r8b,0x0(%r13,%r14,1)
  jmp    L60
  xchg   %ax,%ax
L93:
  test   %ebx,%ebx
  jne    L35
  movslq %r14d,%r15
  jmp    L60
L41:
  mov    %r13,%rdx
  mov    %r9d,%esi
  xor    %eax,%eax
  mov    %r8b,0x8(%rsp)
  call   <conf>
  movzbl 0x8(%rsp),%r8d
  cltq
  jmp    L87
L69:
  movslq %ebx,%rax
  mov    %ebx,%edx
  mov    $0xffffffffffffffff,%r14
  imul   $0x66666667,%rax,%rax
  sar    $0x1f,%edx
  sar    $0x22,%rax
  sub    %edx,%eax
  lea    (%rax,%rax,4),%edx
  add    %edx,%edx
  sub    %edx,%ebx
  lea    0x30(%rbx),%r8d
  mov    %eax,%ebx
  test   %eax,%eax
  je     L104
  mov    $0xfffffffe,%r9d
  mov    $0xffffffffffffffff,%r14
  jmp    L102
L35:
  movabs $0xffffffff00000000,%rdi
  mov    $0xffffffff,%edx
  mov    $0x20,%esi
  add    %r13,%rdi
  call   <memset@plt>
  movslq %ebx,%rax
  mov    %ebx,%edx
  imul   $0x66666667,%rax,%rax
  sar    $0x1f,%edx
  sar    $0x22,%rax
  sub    %edx,%eax
  lea    (%rax,%rax,4),%edx
  add    %edx,%edx
  sub    %edx,%ebx
  lea    0x30(%rbx),%r8d
  mov    %eax,%ebx
  test   %eax,%eax
  jne    L124
  movslq %r14d,%r15
  mov    $0xfffffffffffffffe,%r14
  jmp    L104
L124:
  movslq %r14d,%r15
  mov    $0xfffffffd,%r9d
  mov    $0xfffffffffffffffe,%r14
  jmp    L102
```

assistant: ```c
conf(n, width, buf) char *buf;
{
  auto i, a;
  i = width;
  while (i--)
    buf[i] = ' ';
  buf[(a = n / 10) ? conf(a, --width, buf) : --width] = n % 10 + '0';
  return (++width);
}
```