Register constraints + and =

[Ian Lance Taylor]

<Paul_Koning@Dell.com> writes:

> I thought that the "operand" in a mem:BLK is the pointer to the block,
> not the block itself.  So if the instruction(s) generated don't touch
> the pointer -- a likely answer for a block-move instruction -- then
> the operand would be read-only.  Is that the right interpretation?

Yes.

But many block move instructions do in fact touch the pointer, in that
they update the registers pointing to the starts of the blocks to point
to the ends after the instruction completes.

Ian