user: Please show me the C implementation that matches the assembly code listed below:

```asm
<usage>:
  endbr64
  sub    $0x8,%rsp
  lea    D42(%rip),%rdi
  call   <puts@plt>
  lea    D4(%rip),%rdi
  call   <puts@plt>
  lea    D80(%rip),%rdi
  call   <puts@plt>
  lea    D56(%rip),%rdi
  call   <puts@plt>
  lea    D8(%rip),%rdi
  call   <puts@plt>
  lea    D103(%rip),%rdi
  call   <puts@plt>
  lea    D102(%rip),%rdi
  call   <puts@plt>
  lea    D119(%rip),%rdi
  call   <puts@plt>
  lea    D118(%rip),%rdi
  call   <puts@plt>
  lea    D37(%rip),%rdi
  call   <puts@plt>
  lea    D2(%rip),%rdi
  call   <puts@plt>
  lea    D29(%rip),%rdi
  call   <puts@plt>
  mov    $0xffffffff,%edi
  add    $0x8,%rsp
  jmp    1070 <exit@plt>
```

tool_calls: name: disassemble_data
arguments: data_tag: D42
data_type: string
name: disassemble_data
arguments: data_tag: D4
data_type: string
name: disassemble_data
arguments: data_tag: D80
data_type: string
name: disassemble_data
arguments: data_tag: D56
data_type: string
name: disassemble_data
arguments: data_tag: D8
data_type: string
name: disassemble_data
arguments: data_tag: D103
data_type: string
name: disassemble_data
arguments: data_tag: D102
data_type: string
name: disassemble_data
arguments: data_tag: D119
data_type: string
name: disassemble_data
arguments: data_tag: D118
data_type: string
name: disassemble_data
arguments: data_tag: D37
data_type: string
name: disassemble_data
arguments: data_tag: D2
data_type: string
name: disassemble_data
arguments: data_tag: D29
data_type: string

tool: D42: usage: rdev [ -rv ] [ -o OFFSET ] [ IMAGE [ VALUE [ OFFSET ] ] ]

tool: D4:   rdev /dev/fd0  (or rdev /linux, etc.) displays the current ROOT device

tool: D80:   rdev /dev/fd0 /dev/hda2         sets ROOT to /dev/hda2

tool: D56:   rdev -R /dev/fd0 1              set the ROOTFLAGS (readonly status)

tool: D8:   rdev -r /dev/fd0 627            set the RAMDISK size

tool: D103:   rdev -v /dev/fd0 1              set the bootup VIDEOMODE

tool: D102:   rdev -o N ...                   use the byte offset N

tool: D119:   rootflags ...                   same as rdev -R

tool: D118:   ramsize ...                     same as rdev -r

tool: D37:   vidmode ...                     same as rdev -v

tool: D2: Note: video modes are: -3=Ask, -2=Extended, -1=NormalVga, 1=key1, 2=key2,...

tool: D29:       use -R 1 to mount root readonly, -R 0 for read/write.

assistant: ```c
void usage(void) {
  puts(("usage: rdev [ -rv ] [ -o OFFSET ] [ IMAGE [ VALUE [ OFFSET ] ] ]"));
  puts(("  rdev /dev/fd0  (or rdev /linux, etc.) displays the current ROOT device"));
  puts(("  rdev /dev/fd0 /dev/hda2         sets ROOT to /dev/hda2"));
  puts(("  rdev -R /dev/fd0 1              set the ROOTFLAGS (readonly status)"));
  puts(("  rdev -r /dev/fd0 627            set the RAMDISK size"));
  puts(("  rdev -v /dev/fd0 1              set the bootup VIDEOMODE"));
  puts(("  rdev -o N ...                   use the byte offset N"));
  puts(("  rootflags ...                   same as rdev -R"));
  puts(("  ramsize ...                     same as rdev -r"));
  puts(("  vidmode ...                     same as rdev -v"));
  puts(("Note: video modes are: -3=Ask, -2=Extended, -1=NormalVga, 1=key1, 2=key2,..."));
  puts(("      use -R 1 to mount root readonly, -R 0 for read/write."));
  exit(-1);
}
```