image/svg+xml ADC—Add with Carry Instruction Operand Encoding Description Adds the destination operand (first operand), the source operand (second operand), and the carry (CF) flag and stores the result in the destination operand. The destination operand can be a register or a memory location; the source operand can be an immediate, a register, or a memory location. (However, two memory operands cannot be used in one instruction.) The state of the CF flag represents a carry from a previous addition. When an immediate value is used as an operand, it is sign-extended to the length of the destination operand format. OpcodeInstructionOp/ En 64-bit Mode Compat/ Leg Mode Description 14 ib ADC AL, imm8 IValidValidAdd with carry imm8 to AL. 15 iw ADC AX, imm16 IValidValidAdd with carry imm16 to AX. 15 id ADC EAX, imm32 IValidValidAdd with carry imm32 to EAX. REX.W + 15 id ADC RAX, imm32 IValidN.E.Add with carry imm32 sign extended to 64- bits to RAX. 80 /2 ib ADC r/m8 , imm8 MIValidValidAdd with carry imm8 to r/m8. REX + 80 /2 ib ADC r/m8 * , imm8 MIValidN.E.Add with carry imm8 to r/m8. 81 /2 iw ADC r/m16, imm16 MIValidValidAdd with carry imm16 to r/m16. 81 /2 id ADC r/m32, imm32 MIValidValidAdd with CF imm32 to r/m32. REX.W + 81 /2 id ADC r/m64, imm32 MIValidN.E.Add with CF imm32 sign extended to 64-bits to r/m64. 83 /2 ib ADC r/m16, imm8 MIValidValidAdd with CF sign-extended imm8 to r/m16. 83 /2 ib ADC r/m32, imm8 MIValidValidAdd with CF sign-extended imm8 into r/m32. REX.W + 83 /2 ib ADC r/m64, imm8 MIValidN.E.Add with CF sign-extended imm8 into r/m64. 10 / r ADC r/m8, r8 MRValidValidAdd with carry byte register to r/m8. REX + 10 / r ADC r/m8 * , r8 * MRValidN.E.Add with carry byte register to r/m64. 11 / r ADC r/m16, r16 MRValidValidAdd with carry r16 to r/m16. 11 / r ADC r/m32, r32 MRValidValidAdd with CF r32 to r/m32. REX.W + 11 / r ADC r/m64, r64 MRValidN.E.Add with CF r64 to r/m64. 12 / r ADC r8, r/m8 RMValidValidAdd with carry r/m8 to byte register. REX + 12 / r ADC r8 * , r/m8 * RMValidN.E.Add with carry r/m64 to byte register. 13 / r ADC r16, r/m16 RMValidValidAdd with carry r/m16 to r16. 13 / r ADC r32, r/m32 RMValidValidAdd with CF r/m32 to r32. REX.W + 13 / r ADC r64, r/m64 RMValidN.E.Add with CF r/m64 to r64. NOTES: *In 64-bit mode, r/m8 can not be encoded to access the following byte registers if a REX prefix is used: AH, BH, CH, DH. Op/EnOperand 1Operand 2Operand 3Operand 4 RMModRM:reg (r, w)ModRM:r/m (r)NANA MRModRM:r/m (r, w)ModRM:reg (r)NANA MIModRM:r/m (r, w)imm8/16/32NANA IAL/AX/EAX/RAXimm8/16/32NANA image/svg+xml The ADC instruction does not distinguish between signed or unsigned operands. Instead, the processor evaluates the result for both data types and sets the OF and CF flags to indicate a carry in the signed or unsigned result, respectively. The SF flag indicates the sign of the signed result. The ADC instruction is usually executed as part of a multibyte or multiword addition in which an ADD instruction is followed by an ADC instruction. This instruction can be used with a LOCK prefix to allow the instruction to be executed atomically. In 64-bit mode, the instruction’s default operation size is 32 bits. Using a REX prefix in the form of REX.R permits access to additional registers (R8-R15). Using a REX prefix in the form of REX.W promotes operation to 64 bits. See the summary chart at the beginning of this section for encoding data and limits. Operation DEST := DEST + SRC + CF; Intel C/C ++ Compiler Intrinsic Equivalent ADC:extern unsigned char _addcarry_u8(unsigned char c_in, unsigned char src1, unsigned char src2, unsigned char *sum_out); ADC:extern unsigned char _addcarry_u16(unsigned char c_in, unsigned short src1, unsigned short src2, unsigned short *sum_out); ADC:extern unsigned char _addcarry_u32(unsigned char c_in, unsigned int src1, unsigned char int, unsigned int *sum_out); ADC:extern unsigned char _addcarry_u64(unsigned char c_in, unsigned __int64 src1, unsigned __int64 src2, unsigned __int64 *sum_out); Flags Affected The OF, SF, ZF, AF, CF, and PF flags are set according to the result. Protected Mode Exceptions #GP(0)If the destination is located in a non-writable segment. If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. If the DS, ES, FS, or GS register is used to access memory and it contains a NULL segment selector. #SS(0)If a memory operand effective address is outside the SS segment limit. #PF(fault-code)If a page fault occurs. #AC(0)If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3. #UD If the LOCK prefix is used but the destination is not a memory operand. Real-Address Mode Exceptions #GPIf a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. #SSIf a memory operand effective address is outside the SS segment limit. #UD If the LOCK prefix is used but the destination is not a memory operand. Virtual-8086 Mode Exceptions #GP(0)If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. #SS(0)If a memory operand effective address is outside the SS segment limit. #PF(fault-code)If a page fault occurs. #AC(0)If alignment checking is enabled and an unaligned memory reference is made. #UD If the LOCK prefix is used but the destination is not a memory operand. image/svg+xml Compatibility Mode Exceptions Same exceptions as in protected mode. 64-Bit Mode Exceptions #SS(0)If a memory address referencing the SS segment is in a non-canonical form. #GP(0)If the memory address is in a non-canonical form. #PF(fault-code)If a page fault occurs. #AC(0)If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3. #UD If the LOCK prefix is used but the destination is not a memory operand. 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 .