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

```asm
<copy_in>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x18(%rbp)
  mov    %rsi,-0x20(%rbp)
  movl   $0x0,-0xc(%rbp)
  jmp    L14
L6:
  movl   $0x0,-0x8(%rbp)
  jmp    L21
L7:
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%eax
  add    %edx,%eax
  cltq
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    (%rax),%eax
  mov    %eax,-0x4(%rbp)
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%edx
  mov    -0x8(%rbp),%eax
  add    %edx,%eax
  shl    $0x3,%eax
  movslq %eax,%rdx
  mov    -0x20(%rbp),%rax
  add    %rdx,%rax
  mov    -0x4(%rbp),%edx
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  sar    $0x8,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x1(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  sar    $0x10,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x2(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    -0x4(%rbp),%eax
  sar    $0x18,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x3(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    $0x20,%edx
  mov    -0x4(%rbp),%eax
  mov    %edx,%ecx
  sar    %cl,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x4(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    $0x28,%edx
  mov    -0x4(%rbp),%eax
  mov    %edx,%ecx
  sar    %cl,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x5(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    $0x30,%edx
  mov    -0x4(%rbp),%eax
  mov    %edx,%ecx
  sar    %cl,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x6(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  mov    $0x38,%edx
  mov    -0x4(%rbp),%eax
  mov    %edx,%ecx
  sar    %cl,%eax
  mov    %eax,%edx
  mov    -0xc(%rbp),%eax
  shl    $0x4,%eax
  mov    %eax,%ecx
  mov    -0x8(%rbp),%eax
  add    %ecx,%eax
  shl    $0x3,%eax
  cltq
  lea    0x7(%rax),%rcx
  mov    -0x20(%rbp),%rax
  add    %rcx,%rax
  mov    %dl,(%rax)
  addl   $0x1,-0x8(%rbp)
L21:
  cmpl   $0xf,-0x8(%rbp)
  jle    L7
  addl   $0x1,-0xc(%rbp)
L14:
  cmpl   $0x7,-0xc(%rbp)
  jle    L6
  nop
  nop
  pop    %rbp
  ret
```

assistant: ```c
void copy_in(uint64_t *large_A, char *part_buf_A) {
  int i, j;
  for (i = 0; i < ((512) / (64)); i++) {
    for (j = 0; j < 16; j++) {
#pragma HLS PIPELINE
      uint64_t curr = large_A[i * 16 + j];
      part_buf_A[i * 128 + j * 8 + 0] = (uint8_t)(curr >> 0);
      part_buf_A[i * 128 + j * 8 + 1] = (uint8_t)(curr >> 8);
      part_buf_A[i * 128 + j * 8 + 2] = (uint8_t)(curr >> 16);
      part_buf_A[i * 128 + j * 8 + 3] = (uint8_t)(curr >> 24);
      part_buf_A[i * 128 + j * 8 + 4] = (uint8_t)(curr >> 32);
      part_buf_A[i * 128 + j * 8 + 5] = (uint8_t)(curr >> 40);
      part_buf_A[i * 128 + j * 8 + 6] = (uint8_t)(curr >> 48);
      part_buf_A[i * 128 + j * 8 + 7] = (uint8_t)(curr >> 56);
    }
  }
}
```