user: 请从给定的汇编指令推导出C源代码：

```asm
<increment>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x78,%rsp
  mov    %esi,0xc(%rsp)
  mov    %rdx,0x60(%rsp)
  test   %esi,%esi
  js     L57
  movslq %esi,%rax
  mov    %rdi,%r15
  xor    %ebx,%ebx
  mov    %rax,%rdx
  add    %rdi,%rax
  movzbl (%rax),%esi
  mov    %rax,0x40(%rsp)
  lea    0x1(%rsi),%edi
  mov    %dil,(%rax)
  mov    %edx,%eax
  lea    -0x1(%rdx),%edx
  mov    %edx,0x58(%rsp)
  lea    -0x2(%rax),%edx
  lea    -0x4(%rax),%esi
  mov    %edx,0x5c(%rsp)
  lea    -0x3(%rax),%edx
  mov    %edx,0x54(%rsp)
  lea    -0x5(%rax),%edx
  mov    %esi,0x50(%rsp)
  lea    -0x6(%rax),%esi
  mov    %edx,0x2c(%rsp)
  lea    -0x7(%rax),%edx
  sub    $0x8,%eax
  mov    %eax,0x10(%rsp)
  cltq
  add    %r15,%rax
  mov    %esi,0x14(%rsp)
  mov    %edx,0x28(%rsp)
  mov    %rax,0x68(%rsp)
L64:
  mov    0x40(%rsp),%rbp
  movsbl %dil,%edi
L413:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L158
  movzbl 0x0(%rbp),%eax
  lea    0x1(%rax),%edi
  mov    %dil,0x0(%rbp)
  movsbl %dil,%edi
  test   %edi,%edi
  je     L381
  cmp    $0x79,%edi
  jle    L413
L381:
  mov    0x40(%rsp),%rax
  movb   $0x30,(%rax)
  movslq 0x58(%rsp),%rax
  cmp    $0xffffffff,%eax
  je     L57
  add    %r15,%rax
  movzbl (%rax),%esi
  mov    %rax,0x48(%rsp)
  mov    %rax,%rbx
  mov    %esi,%edx
  mov    %sil,0x18(%rsp)
  lea    0x1(%rdx),%edi
  mov    %dil,(%rax)
L63:
  movsbl %dil,%edi
L152:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L445
  movzbl (%rbx),%eax
  lea    0x1(%rax),%edi
  mov    %dil,(%rbx)
  movsbl %dil,%edi
  test   %edi,%edi
  je     L259
  cmp    $0x79,%edi
  jle    L152
L259:
  mov    0x48(%rsp),%rax
  movb   $0x30,(%rax)
  movslq 0x5c(%rsp),%rax
  cmp    $0xffffffff,%eax
  je     L57
  add    %r15,%rax
  movzbl (%rax),%esi
  mov    %rax,0x38(%rsp)
  mov    %esi,%edx
  mov    %sil,0x18(%rsp)
  lea    0x1(%rdx),%edi
  mov    %dil,(%rax)
  mov    %edi,%eax
L453:
  mov    0x38(%rsp),%rbx
  movsbl %al,%edi
L393:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L299
  movzbl (%rbx),%eax
  lea    0x1(%rax),%edi
  mov    %dil,(%rbx)
  movsbl %dil,%edi
  test   %edi,%edi
  je     L87
  cmp    $0x79,%edi
  jle    L393
L87:
  mov    0x38(%rsp),%rax
  movb   $0x30,(%rax)
  movslq 0x54(%rsp),%rax
  cmp    $0xffffffff,%eax
  je     L57
  add    %r15,%rax
  movzbl (%rax),%esi
  mov    %rax,0x30(%rsp)
  mov    %esi,%edx
  mov    %sil,0x18(%rsp)
  lea    0x1(%rdx),%edi
  mov    %dil,(%rax)
  mov    %edi,%eax
L58:
  mov    0x30(%rsp),%rbx
  movsbl %al,%edi
L213:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L49
  movzbl (%rbx),%eax
  add    $0x1,%eax
  mov    %al,(%rbx)
  movsbl %al,%edi
  cmp    $0x79,%al
  jg     L331
  test   %edi,%edi
  jne    L213
L331:
  mov    0x30(%rsp),%rax
  movb   $0x30,(%rax)
  mov    0x50(%rsp),%eax
  cmp    $0xffffffff,%eax
  je     L57
  movslq %eax,%r13
  add    %r15,%r13
  movzbl 0x0(%r13),%eax
  lea    0x1(%rax),%edi
  mov    %dil,0x0(%r13)
  mov    %edi,%eax
L237:
  movsbl %al,%edi
L90:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L244
  movzbl 0x0(%r13),%eax
  add    $0x1,%eax
  mov    %al,0x0(%r13)
  movsbl %al,%edi
  cmp    $0x79,%al
  jg     L224
  test   %edi,%edi
  jne    L90
L224:
  mov    0x2c(%rsp),%eax
  movb   $0x30,0x0(%r13)
  cmp    $0xffffffff,%eax
  je     L57
  movslq %eax,%rbp
  mov    %r13,0x20(%rsp)
  add    %r15,%rbp
  movzbl 0x0(%rbp),%eax
  lea    0x1(%rax),%edi
  mov    %dil,0x0(%rbp)
  mov    %edi,%eax
L128:
  movsbl %al,%edi
L407:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L31
  movzbl 0x0(%rbp),%eax
  add    $0x1,%eax
  mov    %al,0x0(%rbp)
  movsbl %al,%edi
  cmp    $0x79,%al
  jg     L354
  test   %edi,%edi
  jne    L407
L354:
  mov    0x14(%rsp),%eax
  movb   $0x30,0x0(%rbp)
  cmp    $0xffffffff,%eax
  je     L57
  movslq %eax,%rbx
  movslq 0x28(%rsp),%r12
  add    %r15,%rbx
  movzbl (%rbx),%eax
  lea    0x1(%rax),%edi
  mov    %dil,(%rbx)
  mov    %edi,%eax
L254:
  movsbl %al,%edi
L222:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L402
  movzbl (%rbx),%eax
  lea    0x1(%rax),%edi
  mov    %dil,(%rbx)
  movsbl %dil,%edi
  test   %edi,%edi
  je     L29
  cmp    $0x79,%edi
  jle    L222
L29:
  cmpl   $0xffffffff,0x28(%rsp)
  movb   $0x30,(%rbx)
  je     L57
  lea    (%r15,%r12,1),%r14
  mov    0xc(%rsp),%ecx
  movzbl (%r14),%eax
  lea    -0x9(%rcx),%r13d
  add    $0x1,%eax
  mov    %al,(%r14)
L28:
  movsbl %al,%edi
L305:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L226
  movzbl (%r14),%eax
  add    $0x1,%eax
  mov    %al,(%r14)
  movsbl %al,%edi
  cmp    $0x79,%al
  jg     L79
  test   %edi,%edi
  jne    L305
L79:
  cmpl   $0xffffffff,0x10(%rsp)
  movb   $0x30,(%r14)
  je     L57
  mov    0x68(%rsp),%rax
  mov    %rbx,0x18(%rsp)
  movzbl (%rax),%edx
  mov    %rax,%rbx
  lea    0x1(%rdx),%edi
  mov    %edi,%esi
  mov    %dil,(%rax)
  movsbl %sil,%edi
L255:
  call   <isalnum@plt>
  test   %eax,%eax
  jne    L217
L322:
  movzbl (%rbx),%eax
  add    $0x1,%eax
  mov    %al,(%rbx)
  movsbl %al,%edi
  cmp    $0x79,%al
  jg     L44
  test   %edi,%edi
  jne    L255
L44:
  movb   $0x30,(%rbx)
  mov    0x60(%rsp),%rdx
  mov    %r13d,%esi
  mov    %r15,%rdi
  call   <increment>
  test   %eax,%eax
  je     L57
  movzbl (%rbx),%esi
  movsbl %sil,%edi
  call   <isalnum@plt>
  test   %eax,%eax
  je     L322
  nop
L217:
  mov    0x18(%rsp),%rbx
  movzbl (%r14),%eax
  jmp    L28
  xchg   %ax,%ax
L226:
  movzbl (%rbx),%eax
  jmp    L254
  nopl   0x0(%rax,%rax,1)
L57:
  add    $0x78,%rsp
  xor    %eax,%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
  nopl   0x0(%rax)
L402:
  movzbl 0x0(%rbp),%eax
  jmp    L128
L31:
  mov    0x20(%rsp),%r13
  movzbl 0x0(%r13),%eax
  jmp    L237
L244:
  mov    0x30(%rsp),%rax
  movzbl (%rax),%eax
  jmp    L58
L49:
  mov    0x38(%rsp),%rax
  movzbl (%rax),%eax
  jmp    L453
L299:
  mov    0x48(%rsp),%rax
  movzbl (%rax),%edi
  mov    %rax,%rbx
  jmp    L63
L445:
  mov    0x40(%rsp),%rax
  mov    $0x1,%ebx
  movzbl (%rax),%edi
  jmp    L64
L158:
  add    $0x78,%rsp
  lea    0x1(%rbx),%eax
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
```

assistant: ```c
int increment(char *s, int offset, size_t len) {
  int next = 0;
  if (offset < 0)
    return 0;
  s[offset]++;
  while (!isalnum(s[offset])) {
    int val = ++s[offset];
    if (val >= 'z')
      val = 0;
    if (!val) {
      s[offset] = '0';
      if (!increment(s, offset - 1, len))
        return 0;
      next = 1;
    }
  }
  return next ? 2 : 1;
}
```