Eh, once you know what this routine does, it’s just a matter of looking it up in a table and multiplying by that. Though it’d be interesting to see if he did it in-place or had to repoint it. I wrote this one in place so it’s not intrusive to change it.
edit:
.org 0x028B48
ldr r0, =0x09BCDC01
bx r0
He did repoint it, which is fair, since it does allow for more flexibility than before.