On Thu, 27 Jan 2022 08:05:32 -0800, Ed Jaffe <edja...@phoenixsoftware.com> wrote:
>On 1/27/2022 6:24 AM, Tony Thigpen wrote: >> The answer seems to be that, while not fully known, if one of the >> literals is present, the called program can safely know that they have >> at least the x'08' to x'7F' are to start double-word registers. Do you >> at least agree to that conclusion? > >Whaaaat?! You're saying that you want to depend on what a previous >callee put at +4 to determine something about the length of the >caller's save >area? That makes no sense! It is easy to get confused, isn't it? +4 is set by the program that obtained the save area, not the programs that use it. >Why must we have these "Rube Goldberg" discussions in the first >place? Can't we just follow the linkage conventions as documented >and leave it at that? I agree. If you want your program to be called by existing programs that you have no control over, and don't know how big a save area they provide, you assume they provided only a 72-byte save area. Otherwise, part of your program specifications is the size of save area you require. -- Tom Marchant
