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

```asm
<MD4_Update>:
  endbr64
  test   %rdx,%rdx
  je     L0
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%r12
  mov    %rsi,%rbx
  mov    %rdx,%rbp
  mov    (%rdi),%rdx
  lea    (%rdx,%rbp,8),%eax
  cmp    %rax,%rdx
  jbe    L299
  addq   $0x1,0x18(%rdi)
L299:
  mov    %rbp,%rdx
  shr    $0x1d,%rdx
  add    %rdx,0x18(%r12)
  mov    %rax,(%r12)
  mov    0x8(%r12),%eax
  test   %eax,%eax
  je     L169
  mov    0x10(%r12),%rsi
  mov    %eax,%ecx
  sar    $0x2,%ecx
  mov    %eax,%edx
  and    $0x3,%edx
  movslq %eax,%rdi
  add    %rbp,%rdi
  mov    D44(%rip),%r8
  cmp    (%r8),%rdi
  jb     L246
  movslq %ecx,%rax
  lea    (%rsi,%rax,8),%rdi
  mov    (%rdi),%rax
  cmp    $0x2,%edx
  je     L148
  jg     L240
  test   %edx,%edx
  je     L197
  cmp    $0x1,%edx
  jne    L415
L450:
  movzbl (%rbx),%edx
  shl    $0x8,%rdx
  or     %rdx,%rax
  lea    0x1(%rbx),%rbx
L148:
  lea    0x1(%rbx),%rdx
  movzbl (%rbx),%r8d
  shl    $0x10,%r8
  or     %r8,%rax
L313:
  lea    0x1(%rdx),%rbx
  movzbl (%rdx),%edx
  shl    $0x18,%rdx
  or     %rdx,%rax
L415:
  add    $0x1,%ecx
  mov    %rax,(%rdi)
  mov    D39(%rip),%rax
  cmp    (%rax),%ecx
  jge    L382
  movslq %ecx,%rcx
  mov    %rax,%rdi
L184:
  movzbl (%rbx),%r8d
  movzbl 0x1(%rbx),%edx
  shl    $0x8,%rdx
  movzbl 0x2(%rbx),%eax
  shl    $0x10,%rax
  or     %rax,%rdx
  or     %r8,%rdx
  add    $0x4,%rbx
  movzbl -0x1(%rbx),%eax
  shl    $0x18,%rax
  or     %rdx,%rax
  mov    %rax,(%rsi,%rcx,8)
  add    $0x1,%rcx
  cmp    %ecx,(%rdi)
  jg     L184
L382:
  mov    $0x1,%edx
  mov    %r12,%rdi
  call   <md4_block_host_order@plt>
  movslq 0x8(%r12),%rax
  add    %rbp,%rax
  mov    D44(%rip),%rdx
  sub    (%rdx),%rax
  mov    %rax,%rbp
  movl   $0x0,0x8(%r12)
L169:
  mov    D44(%rip),%rdi
  mov    %rbp,%rax
  mov    $0x0,%edx
  divq   (%rdi)
  mov    %rax,%r13
  mov    %eax,%edx
  test   %eax,%eax
  jg     L337
L119:
  test   %rbp,%rbp
  je     L178
  mov    0x10(%r12),%rdi
  mov    %ebp,0x8(%r12)
  mov    %rbp,%r8
  shr    $0x2,%r8
  and    $0x3,%ebp
  test   %r8d,%r8d
  je     L448
  lea    -0x1(%r8),%eax
  lea    0x4(%rbx,%rax,4),%r9
  mov    %rdi,%rsi
  mov    %rbx,%rcx
L319:
  movzbl (%rcx),%r10d
  movzbl 0x1(%rcx),%edx
  shl    $0x8,%rdx
  movzbl 0x2(%rcx),%eax
  shl    $0x10,%rax
  or     %rax,%rdx
  or     %r10,%rdx
  add    $0x4,%rcx
  movzbl -0x1(%rcx),%eax
  shl    $0x18,%rax
  or     %rdx,%rax
  mov    %rax,(%rsi)
  add    $0x8,%rsi
  cmp    %rcx,%r9
  jne    L319
  lea    -0x1(%r8),%eax
  add    $0x1,%rax
  lea    (%rbx,%rax,4),%rbx
  lea    (%rdi,%rax,8),%rdi
L448:
  movslq %ebp,%rax
  add    %rax,%rbx
  cmp    $0x2,%ebp
  je     L157
  cmp    $0x3,%ebp
  je     L330
  mov    $0x0,%eax
  cmp    $0x1,%ebp
  jne    L449
  mov    $0x0,%edx
  jmp    L208
L197:
  movzbl (%rbx),%eax
  lea    0x1(%rbx),%rbx
  jmp    L450
L240:
  mov    %rbx,%rdx
  jmp    L313
L246:
  add    %ebp,%eax
  mov    %eax,0x8(%r12)
  movslq %edx,%rdi
  add    %rbp,%rdi
  cmp    $0x3,%rdi
  ja     L203
  movslq %ecx,%rcx
  lea    (%rsi,%rcx,8),%rcx
  mov    (%rcx),%rax
  cmp    $0x1,%edx
  je     L255
  cmp    $0x2,%edx
  je     L147
  test   %edx,%edx
  je     L411
L140:
  mov    %rax,(%rcx)
  jmp    L178
L411:
  movzbl (%rbx),%eax
  sub    $0x1,%rbp
  je     L140
  add    $0x1,%rbx
L255:
  movzbl (%rbx),%edx
  shl    $0x8,%rdx
  or     %rdx,%rax
  cmp    $0x1,%rbp
  je     L140
  add    $0x1,%rbx
L147:
  movzbl (%rbx),%edx
  shl    $0x10,%rdx
  or     %rdx,%rax
  jmp    L140
L203:
  mov    %eax,%r8d
  sar    $0x2,%r8d
  and    $0x3,%eax
  mov    %eax,%edi
  test   %edx,%edx
  je     L154
  movslq %ecx,%rax
  mov    (%rsi,%rax,8),%rax
  cmp    $0x2,%edx
  je     L372
  cmp    $0x2,%edx
  jg     L27
  cmp    $0x1,%edx
  jne    L136
L144:
  lea    0x1(%rbx),%rdx
  movzbl (%rbx),%r9d
  shl    $0x8,%r9
  or     %r9,%rax
L159:
  lea    0x1(%rdx),%rbx
  movzbl (%rdx),%edx
  shl    $0x10,%rdx
  or     %rdx,%rax
L27:
  lea    0x1(%rbx),%rdx
  movzbl (%rbx),%r9d
  shl    $0x18,%r9
  or     %r9,%rax
L376:
  lea    0x1(%rcx),%r10d
  movslq %ecx,%r9
  lea    0x0(,%r9,8),%r11
  mov    %rax,(%rsi,%r9,8)
  cmp    %r10d,%r8d
  jle    L21
  lea    0x8(%rsi,%r11,1),%r9
  mov    %r8d,%eax
  sub    %ecx,%eax
  lea    -0x2(%rax),%eax
  lea    0x4(%rdx,%rax,4),%r10
L453:
  movzbl (%rdx),%r11d
  movzbl 0x1(%rdx),%eax
  shl    $0x8,%rax
  movzbl 0x2(%rdx),%ecx
  shl    $0x10,%rcx
  or     %rcx,%rax
  or     %r11,%rax
  add    $0x4,%rdx
  movzbl -0x1(%rdx),%ecx
  shl    $0x18,%rcx
  or     %rcx,%rax
  mov    %rax,(%r9)
  add    $0x8,%r9
  cmp    %rdx,%r10
  jne    L453
L426:
  test   %edi,%edi
  je     L178
  movslq %edi,%rax
  add    %rax,%rdx
  cmp    $0x2,%edi
  je     L12
  cmp    $0x3,%edi
  je     L81
  mov    $0x0,%eax
  cmp    $0x1,%edi
  jne    L309
  mov    $0x0,%ecx
  jmp    L67
L136:
  mov    %rbx,%rdx
  jmp    L376
L154:
  movzbl (%rbx),%eax
  lea    0x1(%rbx),%rbx
  jmp    L144
L372:
  mov    %rbx,%rdx
  jmp    L159
L21:
  mov    %r10d,%r8d
  jmp    L426
L81:
  movzbl -0x1(%rdx),%eax
  shl    $0x10,%rax
  lea    -0x1(%rdx),%rdx
L164:
  movzbl -0x1(%rdx),%ecx
  shl    $0x8,%rcx
  or     %rax,%rcx
  lea    -0x1(%rdx),%rdx
L67:
  movzbl -0x1(%rdx),%eax
  or     %rcx,%rax
L309:
  movslq %r8d,%r8
  mov    %rax,(%rsi,%r8,8)
  jmp    L178
L12:
  mov    $0x0,%eax
  jmp    L164
L337:
  mov    %rbx,%rsi
  mov    %r12,%rdi
  call   <md4_block_data_order@plt>
  mov    D44(%rip),%rax
  imul   (%rax),%r13d
  movslq %r13d,%r13
  add    %r13,%rbx
  sub    %r13,%rbp
  jmp    L119
L330:
  movzbl -0x1(%rbx),%eax
  shl    $0x10,%rax
  lea    -0x1(%rbx),%rbx
L408:
  movzbl -0x1(%rbx),%edx
  shl    $0x8,%rdx
  or     %rax,%rdx
  lea    -0x1(%rbx),%rbx
L208:
  movzbl -0x1(%rbx),%eax
  or     %rdx,%rax
L449:
  mov    %rax,(%rdi)
L178:
  mov    $0x1,%eax
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  ret
L157:
  mov    $0x0,%eax
  jmp    L408
L0:
  mov    $0x1,%eax
  ret
```

assistant: ```c
int MD4_Update(MD4_CTX *c, const void *data_, unsigned long len) {
  const unsigned char *data = data_;
  register MD4_LONG *p;
  register unsigned long l;
  int sw, sc, ew, ec;
  if (len == 0)
    return 1;
  l = (c->Nl + (len << 3)) & 0xffffffffL;
  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 = (((unsigned long)(*((data)++)))), l |= (((unsigned long)(*((data)++))) << 8), l |= (((unsigned long)(*((data)++))) << 16), l |= (((unsigned long)(*((data)++))) << 24), l);
        p[sw] = l;
      }
      md4_block_host_order(c, p, 1);
      len -= (MD4_CBLOCK - c->num);
      c->num = 0;
    } else {
      c->num += 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 = (((unsigned long)(*((data)++)))), l |= (((unsigned long)(*((data)++))) << 8), l |= (((unsigned long)(*((data)++))) << 16), l |= (((unsigned long)(*((data)++))) << 24), 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 = (((unsigned long)(*((data)++)))), l |= (((unsigned long)(*((data)++))) << 8), l |= (((unsigned long)(*((data)++))) << 16), l |= (((unsigned long)(*((data)++))) << 24), 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;
}
```