Re: [Qemu-devel] [PATCH] ARM7TDMI emulation

[Filip Navara <filip.navara@gmail.com>]

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On Tue, Jun 16, 2009 at 10:49 PM, Filip Navara <filip.navara@gmail.com>wrote:

> Do you know of a good summary reference which lists which instructions
>>  are available in each ARM architecture level from ARMv4 up to ARMv7
>> and it's variants?
>>
>
> My main reference are the technical reference manuals for ARM processors
> downloaded from Atmel site. I'm not sure about the license, but it states
> "This document is Open Access. This document has no restriction on
> distribution." Other reference sources are Skyeye emulation (has to be taken
> with grain of salt and checked against the manuals, but it makes distinction
> between v4, v5 and v5e) and Paul Brook.
>
> I've certainly missed handling BLX (at least on three places) in the patch
> and possibly more. I'll post an updated patch soon.
>

The list may not be complete, but this is what I compiled from various
sources, including ARM official documentation. For the ARMv4t emulation I'd
need to do the following:

- Treat CDP2, LDC2, STC2, BLX, MRC2, MCR2, MCRR, SMUL, SMLA, SMULW,
SMLAW, SMLAL, QADD, QSUB, QDADD, QDSUB, BKPT, 64-bit LDR/STR, PLD as
undefined instructions.
- Do not change to/from Thumb mode on LDR/LDM/POP to r15 depending on the
bit 0 of the value.
- Add the base updated data-abort model.

Other changes between ARMv5 and ARMv4 include:

- MULS, MLAS corrupt C flag
- UMULLS, UMLALS, SMULLS and SMLALS corrupt the C and V flags

I don't plan to implement corrupting the flags. Implementing ARMv4 instead
of ARMv4t would then be matter of disabling the BX instruction. Anything I
missed?

Best regards,
Filip Navara

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