user: Demonstrate the C code that generates the assembly output below:

```asm
<compress_location_positions>:
  endbr64
  movzbl (%rsi),%eax
  test   %al,%al
  js     L135
  ret
L135:
  push   %r15
  push   %r14
  push   %r13
  push   %r12
  push   %rbp
  push   %rbx
  sub    $0x8,%rsp
  mov    %rdi,%r13
  mov    %rsi,%rbx
  mov    %edx,%r12d
  mov    %rcx,%rbp
  mov    (%rdi),%r8
  or     $0x10,%eax
  mov    %al,(%rsi)
  lea    -0x1(%rdx),%eax
  test   %eax,%eax
  jle    L65
  cltq
  shl    $0x2,%rax
  lea    (%rcx,%rax,1),%rdx
  lea    -0x4(%rcx,%rax,1),%rdi
  lea    -0x2(%r12),%eax
  shl    $0x2,%rax
  sub    %rax,%rdi
  jmp    L88
L113:
  sub    $0x4,%rdx
  cmp    %rdi,%rdx
  je     L65
L88:
  mov    (%rdx),%ecx
  mov    %ecx,%eax
  shr    $0x8,%eax
  mov    -0x4(%rdx),%esi
  shr    $0x8,%esi
  sub    %esi,%eax
  shl    $0x8,%eax
  movzbl %cl,%ecx
  or     %ecx,%eax
  mov    %eax,(%rdx)
  cmp    $0xfff,%eax
  jbe    L113
  andb   $0xef,(%rbx)
  jmp    L113
L65:
  mov    0x0(%rbp),%edi
  shr    $0x8,%edi
  mov    %r8,%rsi
  call   <compress3@plt>
  mov    %rax,%rsi
  testb  $0x10,(%rbx)
  jne    L198
  cmp    $0x1,%r12d
  jle    L44
  lea    0x4(%rbp),%r14
  lea    -0x2(%r12),%eax
  lea    0x8(%rbp,%rax,4),%r15
L61:
  mov    (%r14),%edi
  shr    $0x8,%edi
  call   <compress3@plt>
  mov    %rax,%rsi
  add    $0x4,%r14
  cmp    %r15,%r14
  jne    L61
  testb  $0x60,(%rbx)
  je     L59
  jmp    L104
L198:
  cmp    $0x1,%r12d
  jle    L31
  lea    -0x1(%r12),%ecx
  mov    $0x0,%eax
  jmp    L19
L125:
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %eax,%edx
  sar    %edx
  movslq %edx,%rdx
  mov    0x4(%rbp,%rax,4),%edi
  shr    $0x8,%edi
  shl    $0x4,%edi
  mov    %dil,(%rsi,%rdx,1)
L137:
  add    $0x1,%rax
  cmp    %rcx,%rax
  je     L165
L19:
  test   $0x1,%al
  je     L125
  mov    %eax,%edx
  shr    $0x1f,%edx
  add    %eax,%edx
  sar    %edx
  movslq %edx,%rdx
  movzbl 0x5(%rbp,%rax,4),%edi
  or     %dil,(%rsi,%rdx,1)
  jmp    L137
L165:
  lea    -0x1(%r12),%edx
L38:
  add    $0x1,%edx
  mov    %edx,%eax
  shr    $0x1f,%eax
  add    %edx,%eax
  sar    %eax
  cltq
  add    %rax,%rsi
L44:
  testb  $0x60,(%rbx)
  jne    L104
  test   %r12d,%r12d
  jle    L104
L59:
  mov    $0x0,%eax
L27:
  mov    0x0(%rbp,%rax,4),%edx
  mov    %dl,(%rsi,%rax,1)
  add    $0x1,%rax
  cmp    %eax,%r12d
  jg     L27
  lea    -0x1(%r12),%eax
  add    $0x1,%rax
  test   %r12d,%r12d
  mov    $0x1,%edx
  cmovle %rdx,%rax
  add    %rax,%rsi
L104:
  mov    %rsi,0x0(%r13)
  add    $0x8,%rsp
  pop    %rbx
  pop    %rbp
  pop    %r12
  pop    %r13
  pop    %r14
  pop    %r15
  ret
L31:
  mov    $0x0,%edx
  jmp    L38
```

assistant: ```c
void compress_location_positions(unsigned char **buf, unsigned char *flag, int frequency, unsigned int *posdata) {
  unsigned char *p = *buf;
  int i, j;
  if ((*flag) & 0x80) {
    (*flag) |= 0x10;
    for (i = frequency - 1; i > 0; i--) {
      posdata[i] = ((unsigned int)((unsigned int)(((int)((unsigned int)(posdata[i]) >> (unsigned int)8)) - ((int)((unsigned int)(posdata[i - 1]) >> (unsigned int)8))) << (unsigned int)8 | (unsigned int)(((int)((unsigned int)(posdata[i]) & (unsigned int)0xff)))));
      if (((int)((unsigned int)(posdata[i]) >> (unsigned int)8)) >= 16)
        (*flag) &= ~0x10;
    }
    p = compress3(((int)((unsigned int)(posdata[0]) >> (unsigned int)8)), p);
    if ((*flag) & 0x10) {
      for (i = 1, j = 0; i < frequency; i++, j++) {
        if (j % 2)
          p[j / 2] |= (unsigned char)((int)((unsigned int)(posdata[i]) >> (unsigned int)8));
        else
          p[j / 2] = (unsigned char)((int)((unsigned int)(posdata[i]) >> (unsigned int)8)) << 4;
      }
      p += ((j + 1) / 2);
    } else {
      for (i = 1; i < frequency; i++)
        p = compress3(((int)((unsigned int)(posdata[i]) >> (unsigned int)8)), p);
    }
    if (!(*flag & 0x60))
      for (i = 0; i < frequency; i++)
        *p++ = (unsigned char)((int)((unsigned int)(posdata[i]) & (unsigned int)0xff));
    *buf = p;
  }
}
```