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Source code

ADC

Add With Carry

stableVMJITAOTinstruction

Encodings

OpcodeInstructionOp/En64-bitCompat/LegacyDescription
14 ibADC AL, imm8IValidValidAdd with carry imm8 to AL.
15 iwADC AX, imm16IValidValidAdd with carry imm16 to AX.
15 idADC EAX, imm32IValidValidAdd with carry imm32 to EAX.
REX.W + 15 idADC RAX, imm32IValidNot encodableAdd with carry imm32 sign extended to 64-bits to RAX.
80 /2 ibADC r/m8, imm8MIValidValidAdd with carry imm8 to r/m8.
81 /2 iwADC r/m16, imm16MIValidValidAdd with carry imm16 to r/m16.
81 /2 idADC r/m32, imm32MIValidValidAdd with CF imm32 to r/m32.
REX.W + 81 /2 idADC r/m64, imm32MIValidNot encodableAdd with CF imm32 sign extended to 64-bits to r/m64.
83 /2 ibADC r/m16, imm8MIValidValidAdd with CF sign-extended imm8 to r/m16.
83 /2 ibADC r/m32, imm8MIValidValidAdd with CF sign-extended imm8 into r/m32.
REX.W + 83 /2 ibADC r/m64, imm8MIValidNot encodableAdd with CF sign-extended imm8 into r/m64.
10 /rADC r/m8, r8MRValidValidAdd with carry byte register to r/m8.
11 /rADC r/m16, r16MRValidValidAdd with carry r16 to r/m16.
11 /rADC r/m32, r32MRValidValidAdd with CF r32 to r/m32.
REX.W + 11 /rADC r/m64, r64MRValidNot encodableAdd with CF r64 to r/m64.
12 /rADC r8, r/m8RMValidValidAdd with carry r/m8 to byte register.
13 /rADC r16, r/m16RMValidValidAdd with carry r/m16 to r16.
13 /rADC r32, r/m32RMValidValidAdd with CF r/m32 to r32.
REX.W + 13 /rADC r64, r/m64RMValidNot encodableAdd with CF r/m64 to r64.

Operand encoding

Each mode is a value of the Op/En column above. It says which field of the encoded instruction carries each operand, in the order they are written, and whether the instruction reads it, writes it or both.

RM

  1. modrm.reg lectura y escrituraModRM byte, reg field (bits 5-3)
  2. modrm.rm lecturaModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them

MR

  1. modrm.rm lectura y escrituraModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
  2. modrm.reg lecturaModRM byte, reg field (bits 5-3)

MI

  1. modrm.rm lectura y escrituraModRM byte, r/m field (bits 2-0); with the SIB byte and the displacement when the mod field asks for them
  2. imm8/16/32immediate after the instruction, as wide as the operand

I

  1. AL/AX/EAX/RAX
  2. imm8/16/32immediate after the instruction, as wide as the operand

Measured cost

Loading measurements from arch-data...

Flags named

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.

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 intrinsics

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.

Exceptions

Protected mode
#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.
#UDIf the LOCK prefix is used but the destination is not a memory operand.
Real address mode
#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.
#UDIf the LOCK prefix is used but the destination is not a memory operand.
Virtual-8086 mode
#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.
#UDIf the LOCK prefix is used but the destination is not a memory operand.
Compatibility mode
Same exceptions as in protected mode.
64-bit mode
#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.
#UDIf the LOCK prefix is used but the destination is not a memory operand.

Sources