user: What would the C source look like for the assembly code provided here?

```asm
<cBytesLshiftfromlentolen>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  sub    $0x50,%rsp
  mov    %edi,-0x34(%rbp)
  mov    %rsi,-0x40(%rbp)
  mov    %edx,-0x38(%rbp)
  mov    %rcx,-0x48(%rbp)
  mov    %r8d,-0x4c(%rbp)
  mov    -0x34(%rbp),%eax
  sar    $0x3,%eax
  mov    %eax,-0x18(%rbp)
  mov    -0x34(%rbp),%eax
  cltd
  shr    $0x1d,%edx
  add    %edx,%eax
  and    $0x7,%eax
  sub    %edx,%eax
  mov    %eax,-0x14(%rbp)
  cmpl   $0x0,-0x14(%rbp)
  jne    L6
  mov    -0x4c(%rbp),%eax
  lea    -0x1(%rax),%edi
  mov    -0x40(%rbp),%rdx
  mov    -0x18(%rbp),%esi
  mov    -0x48(%rbp),%rax
  mov    $0x0,%r8d
  mov    %rdx,%rcx
  mov    %edi,%edx
  mov    %rax,%rdi
  call   <cBytesReplacefromtowithstartingAt@plt>
  jmp    L52
L6:
  movl   $0x0,-0x20(%rbp)
  mov    -0x14(%rbp),%eax
  sub    $0x8,%eax
  mov    %eax,-0x10(%rbp)
  cmpl   $0x0,-0x14(%rbp)
  jle    L171
  mov    -0x14(%rbp),%eax
  mov    $0xff,%edx
  mov    %eax,%ecx
  shr    %cl,%edx
  mov    %edx,%eax
  jmp    L137
L171:
  mov    -0x14(%rbp),%eax
  neg    %eax
  mov    $0xff,%edx
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
L137:
  mov    %eax,-0xc(%rbp)
  mov    -0x18(%rbp),%eax
  sub    $0x1,%eax
  mov    %eax,-0x8(%rbp)
  movl   $0x0,-0x24(%rbp)
  jmp    L14
L28:
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  movb   $0x0,(%rax)
  addl   $0x1,-0x24(%rbp)
L14:
  mov    -0x24(%rbp),%eax
  cmp    -0x8(%rbp),%eax
  jle    L28
  mov    -0x4c(%rbp),%eax
  sub    -0x18(%rbp),%eax
  sub    $0x2,%eax
  mov    %eax,-0x8(%rbp)
  movl   $0x0,-0x24(%rbp)
  jmp    L82
L27:
  mov    -0x24(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x1c(%rbp)
  cmpl   $0x0,-0x14(%rbp)
  jns    L42
  mov    -0x1c(%rbp),%eax
  and    -0xc(%rbp),%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  neg    %eax
  mov    %eax,%ecx
  shr    %cl,%edx
  mov    %edx,%eax
  mov    %eax,%ecx
  jmp    L150
L42:
  mov    -0x1c(%rbp),%eax
  and    -0xc(%rbp),%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
  mov    %eax,%ecx
L150:
  mov    -0x20(%rbp),%eax
  mov    %eax,%esi
  mov    -0x24(%rbp),%edx
  mov    -0x18(%rbp),%eax
  add    %edx,%eax
  movslq %eax,%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
  cmpl   $0x0,-0x10(%rbp)
  jns    L21
  mov    -0x1c(%rbp),%edx
  mov    -0x10(%rbp),%eax
  neg    %eax
  mov    %eax,%ecx
  shr    %cl,%edx
  mov    %edx,%eax
  jmp    L112
L21:
  mov    -0x1c(%rbp),%edx
  mov    -0x10(%rbp),%eax
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
L112:
  mov    %eax,-0x20(%rbp)
  addl   $0x1,-0x24(%rbp)
L82:
  mov    -0x24(%rbp),%eax
  cmp    -0x8(%rbp),%eax
  jle    L27
  mov    -0x8(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x38(%rbp),%eax
  cmp    -0x4(%rbp),%eax
  jg     L79
  movl   $0x0,-0x1c(%rbp)
  jmp    L147
L79:
  mov    -0x4(%rbp),%eax
  movslq %eax,%rdx
  mov    -0x40(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x1c(%rbp)
L147:
  cmpl   $0x0,-0x14(%rbp)
  jns    L46
  mov    -0x1c(%rbp),%eax
  and    -0xc(%rbp),%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  neg    %eax
  mov    %eax,%ecx
  shr    %cl,%edx
  mov    %edx,%eax
  mov    %eax,%ecx
  jmp    L71
L46:
  mov    -0x1c(%rbp),%eax
  and    -0xc(%rbp),%eax
  mov    %eax,%edx
  mov    -0x14(%rbp),%eax
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
  mov    %eax,%ecx
L71:
  mov    -0x20(%rbp),%eax
  mov    %eax,%esi
  mov    -0x4(%rbp),%edx
  mov    -0x18(%rbp),%eax
  add    %edx,%eax
  movslq %eax,%rdx
  mov    -0x48(%rbp),%rax
  add    %rdx,%rax
  or     %esi,%ecx
  mov    %ecx,%edx
  mov    %dl,(%rax)
  cmpl   $0x0,-0x10(%rbp)
  jns    L113
  mov    -0x1c(%rbp),%edx
  mov    -0x10(%rbp),%eax
  neg    %eax
  mov    %eax,%ecx
  shr    %cl,%edx
  mov    %edx,%eax
  jmp    L134
L113:
  mov    -0x1c(%rbp),%edx
  mov    -0x10(%rbp),%eax
  mov    %eax,%ecx
  shl    %cl,%edx
  mov    %edx,%eax
L134:
  mov    %eax,-0x20(%rbp)
L52:
  leave
  ret
```

assistant: ```c
int cBytesLshiftfromlentolen(int shiftCount, unsigned char *pFrom, int lenFrom, unsigned char *pTo, int lenTo) {
  int limit;
  int lastIx;
  int i;
  int carry;
  int byteShift;
  int rShift;
  int mask;
  int digit;
  int bitShift;
  byteShift = ((int)shiftCount >> 3);
  bitShift = shiftCount % 8;
  if (bitShift == 0) {
    return cBytesReplacefromtowithstartingAt(pTo, byteShift, lenTo - 1, pFrom, 0);
  }
  carry = 0;
  rShift = bitShift - 8;
  mask = (((0 - bitShift) < 0) ? ((unsigned)255 >> -(0 - bitShift)) : ((unsigned)255 << (0 - bitShift)));
  limit = byteShift - 1;
  for (i = 0; i <= limit; i += 1) {
    pTo[i] = 0;
  }
  limit = (lenTo - byteShift) - 2;
  ;
l1:;
  for (i = 0; i <= limit; i += 1) {
    digit = pFrom[i];
    pTo[i + byteShift] = ((((bitShift < 0) ? ((unsigned)(digit & mask) >> -bitShift) : ((unsigned)(digit & mask) << bitShift))) | carry);
    carry = ((rShift < 0) ? ((unsigned)digit >> -rShift) : ((unsigned)digit << rShift));
  }
  lastIx = limit + 1;
  if (lastIx > (lenFrom - 1)) {
    digit = 0;
  } else {
    digit = pFrom[lastIx];
  }
  pTo[lastIx + byteShift] = ((((bitShift < 0) ? ((unsigned)(digit & mask) >> -bitShift) : ((unsigned)(digit & mask) << bitShift))) | carry);
  carry = ((rShift < 0) ? ((unsigned)digit >> -rShift) : ((unsigned)digit << rShift));
  ;
l2:;
}
```