"Have you got up? Yes I have."
Translation:Dych chi wedi codi? Ydw.
Do is usually used with past tense verbs to answer "yes" (and naddo for "no"); however, I believe that sometimes it is also used when bod wedi is used rather than the conjugated (one-word) past tense or the version with gwneud such as Wnest ti...?.
I do not yet know enough Welsh to understand your entire answer, but the first half of this is already helpful. Thank you for the context!