Current X87 issues
This is just my list of the things I know are problematic but since they are fixed in my branch, I haven't patched upstream yet.

1. <del>Subtract and division has reverse operators incorrectly set: See https://github.com/FEX-Emu/FEX/pull/3547/commits/efa09a1f9b99f4323e7d280eb530bc1bac6fdcc5</del>
2. fst st(i) is not setting tag properly: See test https://github.com/FEX-Emu/FEX/blob/f15b7b0941d15655b3704122960e063490625259/unittests/ASM/X87/DD_D0_2.asm which fails with current upstream.
3. FXCH should set C1 to Zero: See https://github.com/FEX-Emu/FEX/pull/3547/commits/361fbcf93abdef1a40f1a6046acabec3f2b3775c
4. <del>There's some issue with top off by one in 64bits. D9_F7_F64.asm, RAX should end up with 0x4070000000000000 per my understanding. cc: @CallumDev </del>