Possible bug in UM/MOD

[TG9541]

@MrMarkB found a bug in Dr. Ting's original STM8EF code that's likely also in your code base.

Please refer to TG9541/stm8ef#400

[Picatout]

Bug corrected using umMod.txt
But this path had itself a bug that I corrected replading instruction SRAW X by RRCW X at MMSMb label.

[TG9541]

@Picatout thanks for figuring this and also TG9541/stm8ef#401 out!

[Picatout]

applied applied correction for overflow control solve the issue when the upper part of dividend is == to divisor. udh must be smaller than divisor to avoid overflow. I compared the result with gforth and they agree.

~$ gforth
Gforth 0.7.3, Copyright (C) 1995-2008 Free Software Foundation, Inc.
Gforth comes with ABSOLUTELY NO WARRANTY; for details type license' Type bye' to exit
hex ok
20000 8000 /mod . . 4 0 ok
20000 ffff /mod . . 2 2 ok
20000 8f00 /mod . . 3 5300 ok
20000 7f00 /mod . . 4 400 ok

[TG9541]

Thanks for the collaboration!

I've referenced your repository in the Wiki here