Feature Request: Add support for arithmetic instructions for packed decimal

First of all, Thanks for bringing x86 Linux world to the iOS Platform.

Although SSE2 was partially implemented in https://github.com/ish-app/ish/issues/90#issuecomment-654433012, current version of alpine uses Alpine 3.14, which uses Node 14. (which uses Packed Decimal (for my speculation due to support for `BigInt`))

Currently, according to [/emu/decode.h](https://github.com/ish-app/ish/blob/master/emu/decode.h#L273), It seems `andpd`, `orpd`, `xorpd` is only packed decimal related instruction supported on iSH itself. Frankly, this seems not enough for applications which does arithmetic instructions with packed decimals.

Resolving this issue will resolve:
#1482, #1473

Start by reading emu/decode.h around line 273 and review the existing andpd, orpd, and xorpd support. Identify the packed-decimal arithmetic instructions required by the linked issues #1482 and #1473, then verify that the requested instruction support is covered and those issues are resolved.

Written by the indexing model from the issue text.