* [Qemu-devel] Re: [Qemu-commits] [COMMIT 968a40f] microblaze: Trap on unaligned data accesses. [not found] <200909031110.n83BAwuM023891@d03av03.boulder.ibm.com> @ 2009-09-03 18:10 ` Blue Swirl 2009-09-03 20:01 ` Edgar E. Iglesias 0 siblings, 1 reply; 2+ messages in thread From: Blue Swirl @ 2009-09-03 18:10 UTC (permalink / raw) To: Edgar E. Iglesias; +Cc: qemu-devel On Thu, Sep 3, 2009 at 2:11 PM, Anthony Liguori<aliguori@us.ibm.com> wrote: > From: Edgar E. Iglesias <edgar.iglesias@gmail.com> > +void helper_memalign(uint32_t addr, uint32_t dr, uint32_t wr, uint32_t size) > +{ > + uint32_t mask; > + > + switch (size) { > + case 4: mask = 3; break; > + case 2: mask = 1; break; > + default: > + case 1: mask = 0; break; > + } For additional performance (and to avoid the check for mask == 0 case ;-)), you could perform most of the math above during translation. Sparc32 actually avoids most of these explicit tests, but I still can't understand Fabrice's magic that made it possible. ^ permalink raw reply [flat|nested] 2+ messages in thread
* [Qemu-devel] Re: [Qemu-commits] [COMMIT 968a40f] microblaze: Trap on unaligned data accesses. 2009-09-03 18:10 ` [Qemu-devel] Re: [Qemu-commits] [COMMIT 968a40f] microblaze: Trap on unaligned data accesses Blue Swirl @ 2009-09-03 20:01 ` Edgar E. Iglesias 0 siblings, 0 replies; 2+ messages in thread From: Edgar E. Iglesias @ 2009-09-03 20:01 UTC (permalink / raw) To: Blue Swirl; +Cc: Edgar E. Iglesias, qemu-devel On Thu, Sep 03, 2009 at 09:10:40PM +0300, Blue Swirl wrote: > On Thu, Sep 3, 2009 at 2:11 PM, Anthony Liguori<aliguori@us.ibm.com> wrote: > > From: Edgar E. Iglesias <edgar.iglesias@gmail.com> > > > +void helper_memalign(uint32_t addr, uint32_t dr, uint32_t wr, uint32_t size) > > +{ > > + uint32_t mask; > > + > > + switch (size) { > > + case 4: mask = 3; break; > > + case 2: mask = 1; break; > > + default: > > + case 1: mask = 0; break; > > + } > > For additional performance (and to avoid the check for mask == 0 case > ;-)), you could perform most of the math above during translation. Thanks, I beleive part of what you say is already done. The case 1 is there for completeness but translate.c doesn't call the helper for size 1. I'll move the computing of the mask into translate.c. Thanks, Edgar > > Sparc32 actually avoids most of these explicit tests, but I still > can't understand Fabrice's magic that made it possible. ^ permalink raw reply [flat|nested] 2+ messages in thread
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2009-09-03 18:10 ` [Qemu-devel] Re: [Qemu-commits] [COMMIT 968a40f] microblaze: Trap on unaligned data accesses Blue Swirl
2009-09-03 20:01 ` Edgar E. Iglesias
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