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

```asm
<rej_gamma1m1>:
  endbr64
  push   %rbp
  mov    %rsp,%rbp
  mov    %rdi,-0x18(%rbp)
  mov    %esi,-0x1c(%rbp)
  mov    %rdx,-0x28(%rbp)
  mov    %ecx,-0x20(%rbp)
  movl   $0x0,-0x8(%rbp)
  mov    -0x8(%rbp),%eax
  mov    %eax,-0xc(%rbp)
  jmp    L19
L7:
  mov    -0x8(%rbp),%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  add    $0x1,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x8,%eax
  or     %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  add    $0x2,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x10,%eax
  or     %eax,-0x4(%rbp)
  andl   $0xfffff,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  add    $0x2,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  shr    $0x4,%al
  movzbl %al,%eax
  mov    %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  add    $0x3,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0x4,%eax
  or     %eax,-0x4(%rbp)
  mov    -0x8(%rbp),%eax
  add    $0x4,%eax
  mov    %eax,%edx
  mov    -0x28(%rbp),%rax
  add    %rdx,%rax
  movzbl (%rax),%eax
  movzbl %al,%eax
  shl    $0xc,%eax
  or     %eax,-0x4(%rbp)
  addl   $0x5,-0x8(%rbp)
  mov    -0x4(%rbp),%eax
  cmp    $0xffbfe,%eax
  ja     L42
  mov    -0x4(%rbp),%eax
  mov    $0x87de00,%edx
  mov    %edx,%ecx
  sub    %eax,%ecx
  mov    -0xc(%rbp),%eax
  lea    0x1(%rax),%edx
  mov    %edx,-0xc(%rbp)
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %ecx,%edx
  mov    %edx,(%rax)
L42:
  mov    -0x4(%rbp),%eax
  cmp    $0xffbfe,%eax
  ja     L47
  mov    -0xc(%rbp),%eax
  cmp    -0x1c(%rbp),%eax
  jae    L47
  mov    -0x4(%rbp),%eax
  mov    $0x87de00,%edx
  mov    %edx,%ecx
  sub    %eax,%ecx
  mov    -0xc(%rbp),%eax
  lea    0x1(%rax),%edx
  mov    %edx,-0xc(%rbp)
  mov    %eax,%eax
  lea    0x0(,%rax,4),%rdx
  mov    -0x18(%rbp),%rax
  add    %rdx,%rax
  mov    %ecx,%edx
  mov    %edx,(%rax)
L47:
  mov    -0x20(%rbp),%eax
  sub    $0x5,%eax
  cmp    %eax,-0x8(%rbp)
  ja     L69
L19:
  mov    -0xc(%rbp),%eax
  cmp    -0x1c(%rbp),%eax
  jb     L7
  jmp    L53
L69:
  nop
L53:
  mov    -0xc(%rbp),%eax
  pop    %rbp
  ret
```

assistant: ```c
unsigned int rej_gamma1m1(uint32_t *a, unsigned int len, const unsigned char *buf, unsigned int buflen) {
  unsigned int ctr, pos;
  uint32_t t;
  ctr = pos = 0;
  while (ctr < len) {
    t = buf[pos];
    t |= (uint32_t)buf[pos + 1] << 8;
    t |= (uint32_t)buf[pos + 2] << 16;
    t &= 0xFFFFF;
    t = buf[pos + 2] >> 4;
    t |= (uint32_t)buf[pos + 3] << 4;
    t |= (uint32_t)buf[pos + 4] << 12;
    pos += 5;
    if (t <= 2 * ((8380417U - 1U) / 16U) - 2)
      a[ctr++] = 8380417U + ((8380417U - 1U) / 16U) - 1 - t;
    if (t <= 2 * ((8380417U - 1U) / 16U) - 2 && ctr < len)
      a[ctr++] = 8380417U + ((8380417U - 1U) / 16U) - 1 - t;
    if (pos > buflen - 5)
      break;
  }
  return ctr;
}
```