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UXTB only Thumb2?

Note: This was originally posted on 12th February 2009 at http://forums.arm.com

Hi All,

Arm9 crashed on UXTB instruction because it is not able to decode it. It caused Undef-Instruction exception.

I have been trying to find if UXTB which is a Thumb2 instruction (only supported on ARMv7 onwards) is also supported by Thumb. In other words can I actually use UXTB instruction on Arm9 (ARMv5)?

Thanks a lot,
Samar

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Peter Harris over 12 years ago +1 verified

Note: This was originally posted on 12th February 2009 at http://forums.arm.com UXTB was added in ARMv6 for both ARM and Thumb. It is also in Thumb2, as Thumb2 is a superset of the original Thumb instruction...

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+1 Peter Harris over 12 years ago

Note: This was originally posted on 12th February 2009 at http://forums.arm.com

UXTB was added in ARMv6 for both ARM and Thumb. It is also in Thumb2, as Thumb2 is a superset of the original Thumb instruction set.

> In other words can I actually use UXTB instruction on Arm9 (ARMv5)?

No. ARMv6 is ARM11 upwards.
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+1 Peter Harris over 12 years ago

Note: This was originally posted on 12th February 2009 at http://forums.arm.com

UXTB was added in ARMv6 for both ARM and Thumb. It is also in Thumb2, as Thumb2 is a superset of the original Thumb instruction set.

> In other words can I actually use UXTB instruction on Arm9 (ARMv5)?

No. ARMv6 is ARM11 upwards.
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