image/svg+xml BNDCU/BNDCN—Check Upper Bound Instruction Operand Encoding Description Compare the address in the second operand with the upper bound in bnd. The second operand can be either a register or a memory operand. If the address is higher than the upper bound in bnd.UB, it will set BNDSTATUS to 01H and signal a #BR exception. BNDCU perform 1’s complement operation on the upper bound of bnd first before proceeding with address compar- ison. BNDCN perform address comparison directly using the upper bound in bnd that is already reverted out of 1’s complement form. This instruction does not cause any memory access, and does not read or write any flags. Effective address computation of m32/64 has identical behavior to LEA Operation BNDCU BND, reg IF reg > NOT(BND.UB) Then BNDSTATUS := 01H; #BR; FI; BNDCU BND, mem TEMP := LEA(mem); IF TEMP > NOT(BND.UB) Then BNDSTATUS := 01H; #BR; FI; BNDCN BND, reg IF reg > BND.UB Then BNDSTATUS := 01H; #BR; FI; Opcode/ Instruction Op/En64/32 bit Mode Support CPUID Feature Flag Description F2 0F 1A /r BNDCU bnd, r/m32 RMNE/VMPXGenerate a #BR if the address in r/m32 is higher than the upper bound in bnd.UB (bnb.UB in 1's complement form). F2 0F 1A /r BNDCU bnd, r/m64 RMV/NEMPXGenerate a #BR if the address in r/m64 is higher than the upper bound in bnd.UB (bnb.UB in 1's complement form). F2 0F 1B /r BNDCN bnd, r/m32 RMNE/VMPXGenerate a #BR if the address in r/m32 is higher than the upper bound in bnd.UB (bnb.UB not in 1's complement form). F2 0F 1B /r BNDCN bnd, r/m64 RMV/NEMPXGenerate a #BR if the address in r/m64 is higher than the upper bound in bnd.UB (bnb.UB not in 1's complement form). Op/EnOperand 1Operand 2Operand 3 RMModRM:reg (w)ModRM:r/m (r)NA image/svg+xml BNDCN BND, mem TEMP := LEA(mem); IF TEMP > BND.UB Then BNDSTATUS := 01H; #BR; FI; Intel C/C++ Compiler Intrinsic Equivalent BNDCU .void _bnd_chk_ptr_ubounds(const void *q) Flags Affected None Protected Mode Exceptions #BRIf upper bound check fails. #UDIf the LOCK prefix is used. If ModRM.r/m encodes BND4-BND7 when Intel MPX is enabled. If 67H prefix is not used and CS.D=0. If 67H prefix is used and CS.D=1. Real-Address Mode Exceptions #BRIf upper bound check fails. #UDIf the LOCK prefix is used. If ModRM.r/m encodes BND4-BND7 when Intel MPX is enabled. If 16-bit addressing is used. Virtual-8086 Mode Exceptions #BRIf upper bound check fails. #UDIf the LOCK prefix is used. If ModRM.r/m encodes BND4-BND7 when Intel MPX is enabled. If 16-bit addressing is used. Compatibility Mode Exceptions Same exceptions as in protected mode. 64-Bit Mode Exceptions #UDIf ModRM.r/m and REX encodes BND4-BND15 when Intel MPX is enabled. Same exceptions as in protected mode. This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE .