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Intel Pentium CPU Instruction Set Reference

ADC instruction - Add with Carry

Code Mnemonic Description
14 ib 1 ADC AL, imm8 Add with carry imm8 to AL
15 iw ADC AX, imm16 Add with carry imm16 to AX
15 id ADC EAX, imm32 Add with carry imm32 to EAX
80 /2 ib ADC r/m8, imm8 Add with carry imm8 to r/m8
81 /2 iw ADC r/m16, imm16 Add with carry imm16 to r/m16
81 /2 id ADC r/m32, imm32 Add with CF imm32 to r/m32
83 /2 ib ADC r/m16, imm8 Add with CF sign-extended imm8 to r/m16
83 /2 ib ADC r/m32, imm8 Add with CF sign-extended imm8 into r/m32
10 / r ADC r/m8, r8 Add with carry byte register to r/m8
11 / r ADC r/m16, r16 Add with carry r16 to r/m16
11 / r ADC r/m32, r32 Add with CF r32 to r/m32
12 / r ADC r8, r/m8 Add with carry r/m8 to byte register
13 / r ADC r16, r/m16 Add with carry r/m16 to r16
13 / r ADC r32, r/m32 Add with CF r/m32 to r32


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.

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.

Operands Bytes Clocks
reg, reg 2 1 PU
mem, reg 2 + d(0, 2) 3 PU
reg, mem 2 + d(0, 2) 4 PU
reg, imm 2 + i(1, 2) 1 PU
mem, imm 2 + d(0, 2)+i(1, 2) 3 PU (not pairable if there is a displacement and immediate)
acc, imm 1 + i(1, 2) 1 PU


ID unaffected DF unaffected
VIP unaffected IF unaffected
VIF unaffected TF unaffected
AC unaffected SF sets according to the result
VM unaffected ZF sets according to the result
RF unaffected AF sets according to the result
NT unaffected PF sets according to the result
IOPL unaffected CF sets according to the result
OF sets according to the result