A.75 IBTS: Insert Bit String

IBTS r/m16,reg16              ; o16 0F A7 /r         [386,UNDOC] 
IBTS r/m32,reg32              ; o32 0F A7 /r         [386,UNDOC]

No clear documentation seems to be available for this instruction: the best I've been able to find reads `Takes a string of bits from the second operand and puts them in the first operand'. It is present only in early 386 processors, and conflicts with the opcodes for CMPXCHG486. NASM supports it only for completeness. Its counterpart is XBTS (see section A.167). 



A.167 XBTS: Extract Bit String

XBTS reg16,r/m16              ; o16 0F A6 /r         [386,UNDOC] 
XBTS reg32,r/m32              ; o32 0F A6 /r         [386,UNDOC]

No clear documentation seems to be available for this instruction: the best I've been able to find reads `Takes a string of bits from the first operand and puts them in the second operand'. It is present only in early 386 processors, and conflicts with the opcodes for CMPXCHG486. NASM supports it only for completeness. Its counterpart is IBTS (see section A.75).