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Discussion Groups | AT91SAM ARM | Long Jumps
For users of the Atmel AT91SAM7 and AT91SAM9 ARM CPU chips. Atmel has taken a new direction by combining on chip flash and ram with the ARM CPU on a single die. This provides low cost devices for small systems using the ARM CPU. This group is to exchange information to help users get started and learn how to use the devices.
Long Jumps - "ICLI, Bekir (EXT)" - Jul 3 5:26:42 2008
Hi all,
Some of my code lies in the address region of 0x10000000 and some of
them are in internal SRAM (0x0). To move back and forth I need long
jumps.
I am now asking myself if it would be worth using virtual addressing
with mmu, so that I map my 0x10000000 somewhere near SRAM and I wouldn't
need long jumps.
Would this help for the performance?
>From the performance perspective, how faster is the normal branch than
the long jumps (that the compiler uses with mlong-calls option)?
Regards,
Bekir
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Some of my code lies in the address region of 0x10000000 and some of
them are in internal SRAM (0x0). To move back and forth I need long
jumps.
I am now asking myself if it would be worth using virtual addressing
with mmu, so that I map my 0x10000000 somewhere near SRAM and I wouldn't
need long jumps.
Would this help for the performance?
>From the performance perspective, how faster is the normal branch than
the long jumps (that the compiler uses with mlong-calls option)?
Regards,
Bekir
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
Re: Long Jumps - 42Bastian - Jul 3 8:23:15 2008
Hi,
> Some of my code lies in the address region of 0x10000000 and some of
> them are in internal SRAM (0x0). To move back and forth I need long
> jumps.
> I am now asking myself if it would be worth using virtual addressing
> with mmu, so that I map my 0x10000000 somewhere near SRAM and I wouldn't
> need long jumps.
Why not. It imposes less penalty then long jumps which adds min. 2
instructions.
--
42Bastian
Note: SPAM-only account, direct mail to bs42@...
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )
> Some of my code lies in the address region of 0x10000000 and some of
> them are in internal SRAM (0x0). To move back and forth I need long
> jumps.
> I am now asking myself if it would be worth using virtual addressing
> with mmu, so that I map my 0x10000000 somewhere near SRAM and I wouldn't
> need long jumps.
Why not. It imposes less penalty then long jumps which adds min. 2
instructions.
--
42Bastian
Note: SPAM-only account, direct mail to bs42@...
------------------------------------
(You need to be a member of AT91SAM -- send a blank email to AT91SAM-subscribe@yahoogroups.com )