Reasons:
• piano_fm_part_put_raw(): SI register referenced and not saved on
the stack
• piano_current_note_from(): Would be decompilable… into a mess.
Not worth adding a separate translation unit just for it.
• piano_part_keys_put_raw(): DI register saved before the SI register
• piano_pressed_key_put(): DI register referenced and not immediately
saved on the stack
• piano_label_put_raw(): SI and DI registered referenced and not saved
on the stack
• grcg_setcolor_direct_seg1_raw(): Let's procrastinate this one until
we have to reference all of these instances in C land.
And we could have even emitted that PIANO_KEY_PRESSED_TOP pixel data
into the code segment, by using `#pragma option -z` to give identical
names to both the code and the data segment. At least we can decompile
the first two functions here.
Part of P0135, funded by [Anonymous].
nmlgc