Re: [PATCH H8300] Added -mno-exr option in case of function with "monitor" attribute

[Jeff Law <law at redhat dot com>]

On 03/30/2012 08:13 AM, Sandeep Kumar Singh wrote:
> Hi,
>
> Please find the attached patch to avoid saving of EXR register for
> monitor functions.
>
> By default, in prologue code of a monitor function, EXR register is
> pushed onto the stack. This implementation is not required for H8S/224x
> and 21xx variants of H8S controllers. The behavior can be controlled
> with option "-mno-exr".
>
> Built compiler is only for compiling C language source code. No
> regression found with this patch.
>
> Compiler behavior with different command line options used for
> compilation of code after applying this patch is given below:
>
> * h8300-elf-gcc -mn -S test.c
> test.c:1:0: error: -mn is used without -mh or -ms or -msx
>
> * h8300-elf-gcc -mh -mexr -S test.c
> test.c:1:0: error: -mexr is used without -ms
>
> * h8300-elf-gcc -mh -mno-exr -S test.c
> test.c:1:0: warning: -mno-exr valid only with -ms or -msx
> - Option ignored! [-mno-exr]
>
> * Generated assembly without option '-mno-exr':
> _testmonitor:
>          stc     exr,@-er7
>          mov.l   er0,@-er7
>          stc     ccr,r0l
>
> * Generated assembly with option '-mno-exr':	
> _testmonitor:
>          mov.l   er0,@-er7
>          stc     ccr,r0l
>
> Please review the patch and let me know if there should be any
> modifications in it?	
This looks pretty good.  Just a couple minor issues.

First, do you have an assignment on file with the FSF.  I note several 
other engineers at KPIT have assignments, but I'm not aware of one for 
you.  That will need to be taken care of before we can accept the code.


My recollection was -mint32 was supported on the original H8/300; is 
there something in particular that makes you want to issue an error for 
that case?  Or is my memory incorrect?

In h8300.opt, rather than say "Push exr on stack", would it make more 
sense to say "[Do not] Push extended registers on stack in monitor 
functions"?

Jeff