MASM 6.0 supports these new instructions for the 80486 processor:
| 80486 Instruction | Description | |
| BSWAP | Byte swap | |
| CMPXCHG | Compare and exchange | |
| INVD | Invalidate data cache | |
| INVLPG | Invalidate Translation Lookaside Buffer entry | |
| WBINVD | Write back and invalidate data cache | |
| XADD | Exchange and add |
See the Reference or online help for full descriptions of these new instructions.