user: 请将这段汇编代码片段转换成等效的C代码：

```asm
<MD4_Update>:
  endbr64
  test   %rdx,%rdx
  je     L334
  push   %r14
  push   %r13
  mov    %rsi,%r13
  mov    %edx,%esi
  push   %r12
  mov    D8(%rip),%r12
  push   %rbp
  mov    %rdi,%rbp
  push   %rbx
  mov    (%rdi),%eax
  mov    %rdx,%rbx
  lea    (%rax,%rdx,8),%ecx
  xor    %edx,%edx
  cmp    %ecx,%eax
  mov    %rbx,%rax
  mov    %ecx,(%rdi)
  mov    (%r12),%rcx
  setg   %dl
  shr    $0x1d,%rax
  add    0x10(%rdi),%rdx
  add    %rdx,%rax
  mov    %rax,0x10(%rdi)
  mov    0x4(%rdi),%eax
  test   %eax,%eax
  jne    L38
  cmp    %rcx,%rbx
  jae    L116
L148:
  mov    %esi,0x4(%rbp)
  mov    %rbx,%rsi
  mov    0x8(%rbp),%rcx
  and    $0x3,%esi
  shr    $0x2,%rbx
  je     L346
  shl    $0x2,%rbx
  xor    %eax,%eax
  nopl   0x0(%rax)
L251:
  mov    0x0(%r13,%rax,1),%edx
  mov    %edx,(%rcx,%rax,1)
  add    $0x4,%rax
  cmp    %rax,%rbx
  jne    L251
  add    %rbx,%r13
  add    %rbx,%rcx
L346:
  lea    0x0(%r13,%rsi,1),%rax
  cmp    $0x2,%rsi
  je     L330
  cmp    $0x3,%rsi
  je     L288
  cmp    $0x1,%rsi
  je     L75
  xor    %eax,%eax
  mov    %eax,(%rcx)
L227:
  pop    %rbx
  mov    $0x1,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
  nopl   0x0(%rax)
L38:
  mov    0x8(%rdi),%rsi
  mov    %eax,%edi
  movslq %eax,%rdx
  mov    %eax,%r10d
  sar    $0x2,%edi
  add    %rbx,%rdx
  and    $0x3,%r10d
  movslq %edi,%rdi
  lea    0x0(,%rdi,4),%r8
  lea    (%rsi,%r8,1),%r9
  cmp    %rcx,%rdx
  jb     L297
  mov    (%r9),%edx
  movzbl 0x0(%r13),%eax
  cmp    $0x2,%r10d
  je     L0
  cmp    $0x3,%r10d
  je     L404
  cmp    $0x1,%r10d
  je     L57
  add    $0x1,%r13
  movzbl %al,%edx
L57:
  movzbl 0x0(%r13),%ecx
  lea    0x1(%r13),%rax
  shl    $0x8,%rcx
  or     %ecx,%edx
L397:
  lea    0x1(%rax),%r13
  movzbl (%rax),%eax
  shl    $0x10,%rax
  or     %eax,%edx
L404:
  movzbl 0x0(%r13),%ecx
  lea    0x1(%rdi),%rax
  lea    0x1(%r13),%r10
  shl    $0x18,%rcx
  or     %ecx,%edx
  mov    %edx,(%r9)
  mov    D5(%rip),%rdx
  mov    (%rdx),%rcx
  cmp    %rcx,%rax
  jae    L395
  sub    %r8,%r13
  nopl   0x0(%rax,%rax,1)
L19:
  mov    -0x3(%r13,%rax,4),%edx
  mov    %edx,(%rsi,%rax,4)
  add    $0x1,%rax
  cmp    %rcx,%rax
  jne    L19
  sub    $0x1,%rax
  sub    %rdi,%rax
  lea    (%r10,%rax,4),%r13
L108:
  mov    $0x1,%edx
  mov    %rbp,%rdi
  call   <md4_block_host_order@plt>
  movslq 0x4(%rbp),%rax
  mov    (%r12),%rcx
  movl   $0x0,0x4(%rbp)
  add    %rbx,%rax
  sub    %rcx,%rax
  mov    %rax,%rbx
  cmp    %rax,%rcx
  jbe    L116
L254:
  test   %rbx,%rbx
  jne    L35
L241:
  pop    %rbx
  mov    $0x1,%eax
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  ret
  nopl   (%rax)
L334:
  mov    $0x1,%eax
  ret
  xchg   %ax,%ax
L75:
  xor    %edx,%edx
L349:
  movzbl -0x1(%rax),%eax
  or     %edx,%eax
  mov    %eax,(%rcx)
  jmp    L227
  nop
L288:
  movzbl -0x1(%rax),%edx
  add    $0x2,%r13
  shl    $0x10,%edx
L250:
  movzbl -0x1(%r13),%esi
  lea    -0x1(%r13),%rax
  shl    $0x8,%rsi
  or     %esi,%edx
  jmp    L349
  nopl   0x0(%rax)
L0:
  mov    %r13,%rax
  jmp    L397
  nopl   0x0(%rax,%rax,1)
L116:
  mov    %rbx,%rax
  xor    %edx,%edx
  mov    %r13,%rsi
  mov    %rbp,%rdi
  div    %rcx
  mov    %rax,%rdx
  mov    %rax,%r14
  call   <md4_block_data_order@plt>
  mov    (%r12),%rax
  imul   %r14,%rax
  add    %rax,%r13
  sub    %rax,%rbx
  jmp    L254
  nopl   0x0(%rax)
L297:
  movslq %r10d,%rdx
  add    %ebx,%eax
  add    %rbx,%rdx
  mov    %eax,0x4(%rbp)
  cmp    $0x3,%rdx
  ja     L179
  mov    (%r9),%eax
  cmp    $0x1,%r10d
  je     L127
  cmp    $0x2,%r10d
  je     L131
  test   %r10d,%r10d
  je     L343
L115:
  mov    %eax,(%r9)
  jmp    L241
  nopl   0x0(%rax)
L330:
  mov    %rax,%r13
  xor    %edx,%edx
  jmp    L250
  nopw   0x0(%rax,%rax,1)
L179:
  mov    %eax,%r11d
  and    $0x3,%eax
  sar    $0x2,%r11d
  movslq %r11d,%r11
  test   %r10d,%r10d
  je     L326
  mov    (%r9),%ecx
  cmp    $0x2,%r10d
  je     L319
  cmp    $0x3,%r10d
  je     L225
  cmp    $0x1,%r10d
  je     L128
L326:
  movzbl 0x0(%r13),%ecx
  add    $0x1,%r13
L128:
  movzbl 0x0(%r13),%r10d
  lea    0x1(%r13),%rdx
  shl    $0x8,%r10
  or     %r10d,%ecx
L274:
  lea    0x1(%rdx),%r13
  movzbl (%rdx),%edx
  shl    $0x10,%rdx
  or     %edx,%ecx
L225:
  movzbl 0x0(%r13),%ebx
  lea    0x1(%rdi),%rdx
  lea    0x1(%r13),%r10
  shl    $0x18,%rbx
  or     %ebx,%ecx
  mov    %ecx,(%r9)
  cmp    %rdx,%r11
  jbe    L228
  sub    %r8,%r13
  nop
L192:
  mov    -0x3(%r13,%rdx,4),%ecx
  mov    %ecx,(%rsi,%rdx,4)
  add    $0x1,%rdx
  cmp    %rdx,%r11
  jne    L192
  mov    %rdx,%rcx
  sub    %rdi,%rcx
  lea    -0x4(%r10,%rcx,4),%r10
L228:
  test   %eax,%eax
  je     L241
  movslq %eax,%rcx
  add    %rcx,%r10
  xor    %ecx,%ecx
  movzbl -0x1(%r10),%edi
  cmp    $0x2,%eax
  je     L388
  cmp    $0x3,%eax
  jne    L275
  movzbl %dil,%ecx
  sub    $0x1,%r10
  shl    $0x10,%ecx
L388:
  movzbl -0x1(%r10),%eax
  sub    $0x1,%r10
  shl    $0x8,%rax
  or     %eax,%ecx
L275:
  movzbl -0x1(%r10),%eax
  or     %ecx,%eax
  mov    %eax,(%rsi,%rdx,4)
  jmp    L241
  nopl   0x0(%rax)
L35:
  mov    %ebx,%esi
  jmp    L148
L395:
  mov    %r10,%r13
  jmp    L108
L343:
  movzbl 0x0(%r13),%eax
  sub    $0x1,%rbx
  je     L115
  add    $0x1,%r13
L127:
  movzbl 0x0(%r13),%edx
  shl    $0x8,%rdx
  or     %edx,%eax
  cmp    $0x1,%rbx
  je     L115
  add    $0x1,%r13
L131:
  movzbl 0x0(%r13),%edx
  shl    $0x10,%rdx
  or     %edx,%eax
  jmp    L115
L319:
  mov    %r13,%rdx
  jmp    L274
```

assistant: ```c
int MD4_Update(MD4_CTX *c, const void *data_, size_t len) {
  const unsigned char *data = data_;
  register MD4_LONG *p;
  register MD4_LONG l;
  size_t sw, sc, ew, ec;
  if (len == 0)
    return 1;
  l = (c->Nl + (((MD4_LONG)len) << 3)) & 0xffffffffUL;
  if (l < c->Nl)
    c->Nh++;
  c->Nh += (len >> 29);
  c->Nl = l;
  if (c->num != 0) {
    p = c->data;
    sw = c->num >> 2;
    sc = c->num & 0x03;
    if ((c->num + len) >= MD4_CBLOCK) {
      l = p[sw];
      {
        switch (sc) {
        case 0:
          l = ((unsigned long)(*((data)++)));
        case 1:
          l |= ((unsigned long)(*((data)++))) << 8;
        case 2:
          l |= ((unsigned long)(*((data)++))) << 16;
        case 3:
          l |= ((unsigned long)(*((data)++))) << 24;
        }
      };
      p[sw++] = l;
      for (; sw < MD4_LBLOCK; sw++) {
        ((l) = *((const unsigned int *)(data)), (data) += 4, l);
        p[sw] = l;
      }
      md4_block_host_order(c, p, 1);
      len -= (MD4_CBLOCK - c->num);
      c->num = 0;
    } else {
      c->num += (unsigned int)len;
      if ((sc + len) < 4) {
        l = p[sw];
        {
          switch (sc) {
          case 0:
            l = ((unsigned long)(*((data)++)));
            if (--len == 0)
              break;
          case 1:
            l |= ((unsigned long)(*((data)++))) << 8;
            if (--len == 0)
              break;
          case 2:
            l |= ((unsigned long)(*((data)++))) << 16;
          }
        };
        p[sw] = l;
      } else {
        ew = (c->num >> 2);
        ec = (c->num & 0x03);
        if (sc)
          l = p[sw];
        {
          switch (sc) {
          case 0:
            l = ((unsigned long)(*((data)++)));
          case 1:
            l |= ((unsigned long)(*((data)++))) << 8;
          case 2:
            l |= ((unsigned long)(*((data)++))) << 16;
          case 3:
            l |= ((unsigned long)(*((data)++))) << 24;
          }
        };
        p[sw++] = l;
        for (; sw < ew; sw++) {
          ((l) = *((const unsigned int *)(data)), (data) += 4, l);
          p[sw] = l;
        }
        if (ec) {
          {
            l = 0;
            (data) += ec;
            switch (ec) {
            case 3:
              l = ((unsigned long)(*(--(data)))) << 16;
            case 2:
              l |= ((unsigned long)(*(--(data)))) << 8;
            case 1:
              l |= ((unsigned long)(*(--(data))));
            }
          };
          p[sw] = l;
        }
      }
      return 1;
    }
  }
  sw = len / MD4_CBLOCK;
  if (sw > 0) {
    {
      md4_block_data_order(c, data, sw);
      sw *= MD4_CBLOCK;
      data += sw;
      len -= sw;
    }
  }
  if (len != 0) {
    p = c->data;
    c->num = len;
    ew = len >> 2;
    ec = len & 0x03;
    for (; ew; ew--, p++) {
      ((l) = *((const unsigned int *)(data)), (data) += 4, l);
      *p = l;
    }
    {
      l = 0;
      (data) += ec;
      switch (ec) {
      case 3:
        l = ((unsigned long)(*(--(data)))) << 16;
      case 2:
        l |= ((unsigned long)(*(--(data)))) << 8;
      case 1:
        l |= ((unsigned long)(*(--(data))));
      }
    };
    *p = l;
  }
  return 1;
}
```