TZCNT
REG0=GPRv_R():w MEM0:r:v REG0=GPRv_R():w REG1=GPRv_B():r
x86_64 X86_LEGACY BMI1 BMI1 source: xed
XED_TZCNT_X86_LEGACY_0F_BC_448649
Encoding
| encoding_kind | X86_LEGACY |
| opcode_bytes | BC 0F BC |
| opcode_map | 0F |
| mandatory_prefix | - |
| has_modrm | True |
| cpl | 3 |
| raw_encoding | 0x0F 0xBC refining_f3 TZCNT=1 MOD[mm] MOD!=3 REG[rrr] RM[nnn] MODRM() 0x0F 0xBC refining_f3 TZCNT=1 MOD[0b11] MOD=3 REG[rrr] RM[nnn] |
Operands (4)
| # | Role | Kind | Class / Reg | Width | Access | Visibility | Encoded in |
|---|---|---|---|---|---|---|---|
| 0 | REG0 | REG | w | W | EXPLICIT | MODRM_REG | |
| 1 | MEM0 | MEM | v | R | EXPLICIT | MODRM_RM | |
| 2 | REG1 | REG | w | W | EXPLICIT | MODRM_REG | |
| 3 | REG2 | REG | R | EXPLICIT | MODRM_REG |
Flag effects (6)
CF = WRITE
PF = UNDEFINED
AF = UNDEFINED
ZF = WRITE
SF = UNDEFINED
OF = UNDEFINED
Micro-ops sequence (0)
No micro-ops authored for this encoding. Emulator semantics not yet defined — decoder still works.