IBM 360 Model 50 information?

[Ken Shirriff]

I'm writing a S/360 Model 50 emulator that runs at the microcode level, in
order to drive a Model 50 front panel accurately. I'm about 80% of the way
there, but there are some microcode operations that I haven't figured out.
So I figured I'd ask if anyone has obscure Model 50 manuals that aren't on
bitsavers, or perhaps even the ALDs.

I was surprised at how extremely different the microcode is from the 360
instruction set. I've figured out a bunch of the strange
micro-instructions, such as S47ΩE, which ORs the emit field into flags 4
through 7. But there are many micro-instructions that still puzzle me,
like F→FPSL4 which maybe a floating point shift left 4 and 1→BS*MB which
does something with byte stats. So if anyone happens to have a Model 50
microcode programming manual sitting around, please let me know :-)

Thanks,
Ken