Halfword loads and stores

[SteNews]

Hello,

Later ARMs provide LDRH and STRH instructions, but that does not mean you
can use them. For example, the RISC PC I/O system will give unpredictable
results if you try to use them (especially on uncached memory).

My hardware-related question is: does the Kinetic board support LRDH and
STRH and do the other various machine flavours out there (i.e. RiscStation
and MD machines)? I know that Iyonix does.

Steve

--
Steve Revill @ Home
Note: All opinions expressed herein are my own.

[druck]

On 18 Jul 2003 SteNews <sarev.of.aona.DELETE@ukgateway.net> wrote: Later ARMs provide LDRH and STRH instructions, but that does not mean you can use them. For example, the RISC PC I/O system will give unpredictable results if you try to use them (especially on uncached memory). My hardware-related question is: does the Kinetic board support LRDH and STRH and do the other various machine flavours out there (i.e. RiscStation and MD machines)? I know that Iyonix does.

They may work with memory located in the Kinetic card. However the physical
location of a memory page could be changed by the OS at any time, it is not
recommended that they are used.

---druck

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The ARM Club Free Software - http://www.armclub.org.uk/free/
The 32bit Conversions Page - http://www.quantumsoft.co.uk/druck/

[Theo Markettos]

SteNews <sarev.of.aona.DELETE@ukgateway.net> wrote: Hello, Later ARMs provide LDRH and STRH instructions, but that does not mean you can use them. For example, the RISC PC I/O system will give unpredictable results if you try to use them (especially on uncached memory). My hardware-related question is: does the Kinetic board support LRDH and STRH and do the other various machine flavours out there (i.e. RiscStation and MD machines)? I know that Iyonix does.

IIRC Kinetic does to SDRAM, but not to DRAM or VRAM. So you can try, but if
you happen to hit a piece of memory that's not in SDRAM it'll silently go
wrong.

AIUI LDRH/STRH are StrongARM (I think ARMv4) inventions, so aren't present
on ARM7 (eg ARM7500(FE)) cores. I can't comment for Pace's ARM9 boards.

Theo

--
Theo Markettos theo@markettos.org.uk
Larisa, Greece theom@chiark.greenend.org.uk
http://www.markettos.org.uk/