Decoder fails to decode some weird instructions

[0xd4d]

Version: latest master = 4d4fe4c

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Can't decode these instructions. REX.X bit should be ignored.

• 66420F1ACA = bndmov = unused REX.X bit is set
• 66420F1BCA = bndmov = unused REX.X bit is set

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Can't decode these instructions. Rounding control should be ignored.

Intel SDM: EVEX.W0 version: attempt to encode this instruction with EVEX embedded rounding is ignored.

• 62E10F182AD3 = vcvtsi2sd gpr32 with ignored rc bits
• 62E10F187BD3 = vcvtusi2sd gpr32 with ignored rc bits

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These decode without errors in minimal mode because ZydisDecodeOperands() isn't called:

• 0F1A0D34125AA5
• 0F1B0D34125AA5

[flobernd]

Hi there,

first of all thanks for reporting these issues. Correctness is very important for us.

Can't decode these instructions. REX.X bit should be ignored

You are correct I guess. Not entirely sure why I put a check to actively prevent REX.X for BND registers. The .X component is only used to extend RM encoded registers for EVEX/MVEX anyways and should not affect BND.

Fixed in: d7ba09a

Can't decode these instructions. Rounding control should be ignored.

You are correct here as well. I had a constraint requiring all E10NF exception-class instructions to have EVEX.B set to 0 in the instruction-editor. I removed that condition to allow these two exceptions.

Fixed in: 5f2dde8

These decode without errors in minimal mode because ZydisDecodeOperands() isn't called

Will check this case later today.

[flobernd]

Fixed the last problem as well by adding a new constraint for MIB memory operands to disallow relative addressing.

[0xd4d]

I think your RIP-rel fix forgot the 64-bit check:

• 0F1A0D34125AA5: fails to decode in 32-bit mode now

[flobernd]

I think your RIP-rel fix forgot the 64-bit check

Oh well .. seems like I'm really not concentrated today. Thanks for reporting again. Should be fixed now.