This is the mail archive of the gcc@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]

Re: mips.md patch for 3900



Jim Wilson writes:
 > 	* config/mips/mips.md (dslot): Move after definition of "cpu"
 > 	attribute.  Handle r3900 case.
 > 
 > This is a workaround for a hardware bug isn't it?  I think it needs a little
 > more explanation in the comments, in case there are later revision of this
 > processor which do not have the bug.

No.  The r3900 is mostly a mips1 part with some (but not all) 
mips2 instructions/features; in particular the load delay slot
is not manditory on the 3900 (because the pipeline will insert
nops if needed like mips2 chips).

This patch changes dslot to indicate that the load delay slot
on the 3900 is not manditory dispite the fact that "cpu_isa"
is 1 for the 3900.

                                   -gavin...



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]