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Re: HP-PA ABI issues - framepointer handling
- To: law at redhat dot com
- Subject: Re: HP-PA ABI issues - framepointer handling
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Date: Fri, 10 Nov 2000 14:04:12 -0500 (EST)
- Cc: gcc at gcc dot gnu dot org, bosch at gnat dot com
> In message <200010191939.PAA04817@hiauly1.hia.nrc.ca>you write:
> > HP also doesn't follow its own 32 bit ABI. For non leaf procedures,
> > HP cc saves the return pointer and adjusts the stack for the new frame.
> > It doesn't save sp at SP-0 or the previous sp at SP-4. The previous is
> > only required by the ABI if the current frame is noncontiguous with the
> > previous frame, has a variable size or is used with the static link (SP-16)
> If I recall correctly, the unwinding conventions do not mandate that you save
> the current or previous stack pointer, only that if you do save it, that it
> gets saved into a specific location within the frame.
The last sentence in my comment paraphrases a statement in "The 32-bit
PA_RISC Runtime Architecture Document", HP-UX 10.20, Version 3.0, page 14.
Thus, there are circumstances where saving the previous SP is required.
Dave
--
J. David Anglin dave.anglin@nrc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)