On Wed, 6 Nov 2019 at 18:08, Steve Thompson <ste...@copper.net> wrote:
> But my point was, the contents of R0 may be relevant. Implying it > never matters is not quite right. When specified as a base or index register, i.e. as Bn or Xn in any instruction with such fields in its description, R0 is treated as if it contained 0 when evaluated as part of the address arithmetic process. This is true regardless of Amode, Translation mode (DAT, primary/secondary/home/AR modes), or prefixing, all of which control the interpretation of an "effective address", which has already been generated from an "intermediate value" which in turn was formed through a process that ignores the content of R0. > BTW, I went and looked it up (I have quite a few copies of the > PoOP from different points in time). Where did you find that the R0 content matters in these cases? Tony H.
