Add MIPS Unaligned Instruction Fix analyzer.

[twevs]

The MIPS Unaligned Instruction Fix analyzer, available for MIPS processors in the Ghidra repository, leads to considerably improved decompilation of lwl/lwr and swl/swr pairs, allowing one to make sense of struct copies, such that for instance:

  if ((pControl->field_55_flags & 2) == 0) {
    puVar1 = (undefined *)((int)&(pControl->field_0_position).vy + 1);
    uVar17 = (uint)puVar1 & 3;
    uVar18 = (uint)pControl & 3;
    uVar19 = (*(int *)(puVar1 + -uVar17) << (3 - uVar17) * 8 |
             in_t0 & 0xffffffffU >> (uVar17 + 1) * 8) & -1 << (4 - uVar18) * 8 |
             *(uint *)((int)pControl - uVar18) >> uVar18 * 8;
    puVar1 = (undefined *)((int)&(pControl->field_0_position).pad + 1);
    uVar17 = (uint)puVar1 & 3;
    psVar2 = &(pControl->field_0_position).vz;
    uVar18 = (uint)psVar2 & 3;
    uVar18 = (*(int *)(puVar1 + -uVar17) << (3 - uVar17) * 8 |
             in_t1 & 0xffffffffU >> (uVar17 + 1) * 8) & -1 << (4 - uVar18) * 8 |
             *(uint *)((int)psVar2 - uVar18) >> uVar18 * 8;
    puVar1 = (undefined *)((int)&(pControl->field_10_pStruct_hzd_unknown).field_14_vec.vy + 1);
    uVar17 = (uint)puVar1 & 3;
    puVar9 = (uint *)(puVar1 + -uVar17);
    *puVar9 = *puVar9 & -1 << (uVar17 + 1) * 8 | uVar19 >> (3 - uVar17) * 8;
    pSVar16 = &(pControl->field_10_pStruct_hzd_unknown).field_14_vec;
    uVar17 = (uint)pSVar16 & 3;
    puVar9 = (uint *)((int)pSVar16 - uVar17);
    *puVar9 = *puVar9 & 0xffffffffU >> (4 - uVar17) * 8 | uVar19 << uVar17 * 8;
    puVar1 = (undefined *)((int)&(pControl->field_10_pStruct_hzd_unknown).field_14_vec.pad + 1);
    uVar17 = (uint)puVar1 & 3;
    puVar9 = (uint *)(puVar1 + -uVar17);
    *puVar9 = *puVar9 & -1 << (uVar17 + 1) * 8 | uVar18 >> (3 - uVar17) * 8;
    psVar2 = &(pControl->field_10_pStruct_hzd_unknown).field_14_vec.vz;
    uVar17 = (uint)psVar2 & 3;
    puVar9 = (uint *)((int)psVar2 - uVar17);
    *puVar9 = *puVar9 & 0xffffffffU >> (4 - uVar17) * 8 | uVar18 << uVar17 * 8;
    (pControl->field_10_pStruct_hzd_unknown).field_14_vec.pad = (pControl->field_8_rotator).vy;
    GM_ActControl_helper6_8002A538((int)pHzd,(ushort *)&pControl->field_10_pStruct_hzd_unknown);
  }

becomes

  if ((pControl->field_55_flags & 2) == 0) {
    uVar16 = *(undefined4 *)&(pControl->field_0_position).vz;
    *(undefined4 *)&(pControl->field_10_pStruct_hzd_unknown).field_14_vec =
         *(undefined4 *)&pControl->field_0_position;
    *(undefined4 *)&(pControl->field_10_pStruct_hzd_unknown).field_14_vec.vz = uVar16;
    (pControl->field_10_pStruct_hzd_unknown).field_14_vec.pad = (pControl->field_8_rotator).vy;
    GM_ActControl_helper6_8002A538((int)pHzd,(ushort *)&pControl->field_10_pStruct_hzd_unknown);
  }

and the SVECTOR copy

  puVar1 = (undefined *)((int)&local_28[1].vy + 1);
  uVar2 = (uint)puVar1 & 3;
  puVar3 = (uint *)(puVar1 + -uVar2);
  *puVar3 = *puVar3 & -1 << (uVar2 + 1) * 8 | uStack48._0_4_ >> (3 - uVar2) * 8;
  local_28[1]._0_4_ = uStack48._0_4_;
  puVar1 = (undefined *)((int)&local_28[1].pad + 1);
  uVar2 = (uint)puVar1 & 3;
  puVar3 = (uint *)(puVar1 + -uVar2);
  *puVar3 = *puVar3 & -1 << (uVar2 + 1) * 8 | uStack48._4_4_ >> (3 - uVar2) * 8;
  local_28[1]._4_4_ = uStack48._4_4_;

becomes simply

  local_28[1]._0_4_ = uStack48._0_4_;
  local_28[1]._4_4_ = uStack48._4_4_;

Given its utility in making sense of decompiled PlayStation code, it seems it would therefore make sense to add it to the list of available analyzers for the PSX.

[fatalis]

This is incredibly useful :+1:

[lab313ru]

Merged via: c4a720a458a2312a16912c662f88e7606354499a.