Fork channel

Create a new channel as a copy of main.

Rename channel

Rename main to:

Delete channel

Delete main? This cannot be undone.

dfb-thumb.txt
# RUN: llvm-mc -disassemble -triple thumbv8-none-eabi -mcpu=cortex-r52 -show-encoding < %s | FileCheck %s --check-prefix=CHECK-DFB
# RUN: llvm-mc -disassemble -triple thumbv8-none-eabi -mcpu=cortex-r52 -mattr=-dfb -show-encoding < %s | FileCheck %s --check-prefix=CHECK-NODFB

# CHECK-DFB:   dfb                             @ encoding: [0xbf,0xf3,0x4c,0x8f]
# CHECK-NODFB: dsb     #0xc                    @ encoding: [0xbf,0xf3,0x4c,0x8f]
[0xbf,0xf3,0x4c,0x8f]