0+_240 is positive but 0+*_240 240 is negative

[ktye]

uptype is wrong for char atoms. maybe Kc should be:

func Kc(x int32) K { return K(0xff&uint32(x)) | K(ct)<<59 }

[ktye]

no. Kc is ok.

Flr needs sign extension of xp, e.g.

case 1:
return Kc(int32(int8(xp)))

but there is no such operation in the abstract machine