- // VEX_L - Stands for a bit in the VEX opcode prefix meaning the current
- // instruction uses 256-bit wide registers. This is usually auto detected if
- // a VR256 register is used, but some AVX instructions also have this field
- // marked when using a f256 memory references.
- VEX_L = 1U << 4
+ /// VEX_L - Stands for a bit in the VEX opcode prefix meaning the current
+ /// instruction uses 256-bit wide registers. This is usually auto detected
+ /// if a VR256 register is used, but some AVX instructions also have this
+ /// field marked when using a f256 memory references.
+ VEX_L = 1U << 4,
+
+ /// Has3DNow0F0FOpcode - This flag indicates that the instruction uses the
+ /// wacky 0x0F 0x0F prefix for 3DNow! instructions. The manual documents
+ /// this as having a 0x0F prefix with a 0x0F opcode, and each instruction
+ /// storing a classifier in the imm8 field. To simplify our implementation,
+ /// we handle this by storeing the classifier in the opcode field and using
+ /// this flag to indicate that the encoder should do the wacky 3DNow! thing.
+ Has3DNow0F0FOpcode = 1U << 5