user: 提供的汇编代码用C语言表示会是什么样子：

```asm
<uuencode>:
  endbr64
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%rbx
  mov    %rsi,%r12
  mov    %rdx,%rbp
  mov    %rcx,%r11
  test   %rcx,%rcx
  jne    L48
  mov    %rdx,%rdi
  call   <strlen@plt>
  mov    %rax,%r11
L48:
  cmp    $0x2,%r12
  jbe    L139
  sub    $0x3,%r12
  mov    $0x0,%eax
  mov    $0x0,%edi
  mov    $0x60,%esi
  mov    $0x3,%r15d
  sub    %rbp,%r15
  jmp    L105
L4:
  mov    $0x2d,%edx
L137:
  lea    0x20(%rdx),%r10
L37:
  lea    0x1(%rax),%r8
  mov    %r10b,(%rbx,%rax,1)
  cmp    %r8,%r12
  seta   %dl
  cmp    %rdi,%r11
  seta   %al
  test   %al,%dl
  je     L21
  test   %r10,%r10
  je     L21
  lea    0x0(%rbp,%rdi,1),%rdx
  lea    (%rbx,%r8,1),%rcx
  mov    %r8,%rax
  mov    %rdi,%r9
  mov    %r15,%r13
  sub    %rdi,%r13
L16:
  movzbl (%rdx),%edi
  sar    $0x2,%dil
  lea    0x20(%rdi),%r8d
  mov    %r8d,%edi
  cmove  %esi,%edi
  mov    %dil,(%rcx)
  movsbl (%rdx),%r8d
  shl    $0x4,%r8d
  and    $0x30,%r8d
  mov    %r8b,0x1(%rcx)
  movzbl 0x1(%rdx),%edi
  sar    $0x4,%dil
  or     %r8d,%edi
  lea    0x20(%rdi),%r8d
  test   %dil,%dil
  mov    %r8d,%edi
  cmove  %esi,%edi
  mov    %dil,0x1(%rcx)
  movsbl 0x1(%rdx),%r8d
  shl    $0x2,%r8d
  and    $0x3c,%r8d
  mov    %r8b,0x2(%rcx)
  movzbl 0x2(%rdx),%edi
  sar    $0x6,%dil
  or     %r8d,%edi
  lea    0x20(%rdi),%r8d
  test   %dil,%dil
  mov    %r8d,%edi
  cmove  %esi,%edi
  mov    %dil,0x2(%rcx)
  add    $0x3,%r9
  movzbl 0x2(%rdx),%edi
  and    $0x3f,%edi
  lea    0x20(%rdi),%r8d
  test   %dil,%dil
  mov    %r8d,%edi
  cmove  %esi,%edi
  mov    %dil,0x3(%rcx)
  add    $0x4,%rax
  lea    0x0(%r13,%rdx,1),%rdi
  cmp    %rdi,%r10
  seta   %r8b
  cmp    %rax,%r12
  seta   %dil
  cmp    %r9,%r11
  seta   %r14b
  and    %r14d,%edi
  add    $0x3,%rdx
  add    $0x4,%rcx
  test   %dil,%r8b
  jne    L16
  mov    %r9,%rdi
L18:
  cmp    %rax,%r12
  jbe    L31
  lea    0x1(%rax),%rdx
  movb   $0xd,(%rbx,%rax,1)
  add    $0x2,%rax
  movb   $0xa,(%rbx,%rdx,1)
L31:
  cmp    %rdi,%r11
  jbe    L80
L105:
  cmp    %rdi,%r11
  jb     L80
  cmp    %r12,%rax
  jae    L80
  lea    0x2d(%rdi),%rdx
  cmp    %r11,%rdx
  jbe    L4
  mov    $0x60,%r10d
  mov    %r11,%rdx
  sub    %rdi,%rdx
  je     L37
  jmp    L137
L21:
  mov    %r8,%rax
  jmp    L18
L80:
  cmp    %r12,%rax
  jae    L52
  movb   $0x0,(%rbx,%rax,1)
  lea    0x1(%rax),%rax
L52:
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L139:
  mov    $0xffffffff,%eax
  jmp    L52
```

assistant: ```c
int uuencode(char *target, size_t tlen, const char *source, size_t slen) {
  size_t rd = 0;
  size_t wr = 0;
  size_t block;
  size_t len;
  if (slen == 0)
    slen = strlen(source);
  if (tlen < 3)
    return (-1);
  tlen -= 3;
  while (rd <= slen && wr < tlen) {
    len = 45;
    if (rd + len > slen)
      len = slen - rd;
    if ((len) == 0)
      (len) = '`';
    else
      (len) += ' ';
    ;
    target[wr++] = len;
    block = 0;
    while (block < len && wr < tlen && rd < slen) {
      target[wr] = source[rd] >> 2;
      if ((target[wr]) == 0)
        (target[wr]) = '`';
      else
        (target[wr]) += ' ';
      ;
      wr++;
      target[wr] = (source[rd++] & 0x03) << 4;
      target[wr] |= source[rd] >> 4;
      if ((target[wr]) == 0)
        (target[wr]) = '`';
      else
        (target[wr]) += ' ';
      ;
      wr++;
      target[wr] = (source[rd++] & 0x0f) << 2;
      target[wr] |= source[rd] >> 6;
      if ((target[wr]) == 0)
        (target[wr]) = '`';
      else
        (target[wr]) += ' ';
      ;
      wr++;
      target[wr] = source[rd++] & 0x3f;
      if ((target[wr]) == 0)
        (target[wr]) = '`';
      else
        (target[wr]) += ' ';
      ;
      wr++;
      block += 3;
    }
    if (wr < tlen) {
      target[wr++] = '\r';
      target[wr++] = '\n';
    }
    if (rd >= slen)
      break;
  }
  if (wr < tlen)
    target[wr++] = 0;
  return (wr);
}
```