ARM patches applied

Richard Earnshaw
Sun Feb 28 18:15:00 GMT 1999

>   > See below (arm_return_in_memory).  As a note here, I don't like the way 
>   > the netbsd port is doing that (it uses non-pcc struct returning to compile 
>   > just one file in the standard library which contains the soft-float code, 
>   > it then needs structures of 2 words to be returned in registers -- very 
>   > dodgy, it would be better to fix the source file in libc so the undef 
>   > wasn't needed).
> Haven't the netbsd folks gone back and forth a couple times on this issue; I
> seem to recall it being discussed before.
> The problem (as I see it) is if they change then they break backwards
> compatibility. 
Yes, but in the end the issue really turned out to be that they use PCC 
struct returning: for them all structs and unions return in memory.  
However, they have one file in libc which needs to return a structure in 
registers (so that they can soft-float emulate returning a double in 
r0,r1).  They currently hack this by compiling that file with 
-freg-strcut-return (or whatever).  With the new definition of 
RETURN_IN_MEMORY this all breaks because the APCS mandates that structures 
larger than a word must always be returned in memory.  The correct fix, 
long-term is to make the soft-float emulation code return a long long; 
whereupon the #undef of RETURN_IN_MEMORY can be deleted.


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