I'm finding this sequence multiple times; part of it or exactly this keeps on appearing in my compiler's output. I think it's performing a modulo by the Q16+8 value 10.0, then converting the number to ASCII then printing it. Part of the Q16+8 decimal print function, I think.
(Also - 0x30 is ASCII '0', not 'H')
#assembly
Found it, part of my ASCII.s stdlib. Came up with a change, which compiles to about 24 bytes, compared to about 55 bytes, but uses a loop. These print out the tenths, hundredths, and thousandths places of a decimal number; I think I'll keep the former code, since it is branchless, I/O aside, and since I might want to remove the thousandths place anyway (since Q16+8 numbers aren't quite that precise).
Yeah, definitely appears to be part of that function. That's modulo code for sure, too.