모두의 코드
ADOX (Intel x86/64 assembly instruction)

작성일 : 2020-09-01 이 글은 28 번 읽혔습니다.

ADOX

Unsigned Integer Addition of Two Operands with Overflow Flag

참고 사항

아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.

Opcode/
Instruction
Op/
En
64/32bit
Mode
Support
CPUID
Feature
Flag
Description
F3 0F 38 F6 /r
ADOX r32 r/m32
RMV/VADXUnsigned addition of r32 with OF, r/m32 to r32, writes OF.
F3 REX.w 0F 38 F6 /r
ADOX r64 r/m64
RMV/NEADXUnsigned addition of r64 with OF, r/m64 to r64, writes OF.

Instruction Operand Encoding

Op/EnOperand 1Operand 2Operand 3Operand 4
RMModRM:reg (r, w)ModRM:r/m (r)NANA

Description

Performs an unsigned addition of the destination operand (first operand), the source operand (second operand) and the overflow-flag (OF) and stores the result in the destination operand. The destination operand is a general-purpose register, whereas the source operand can be a general-purpose register or memory location. The state of OF represents a carry from a previous addition. The instruction sets the OF flag with the carry generated by the unsigned addition of the operands.

The ADOX instruction is executed in the context of multi-precision addition, where we add a series of operands with a carry-chain. At the beginning of a chain of additions, we execute an instruction to zero the OF (e.g. XOR).

This instruction is supported in real mode and virtual-8086 mode. The operand size is always 32 bits if not in 64-bit mode.

In 64-bit mode, the default operation size is 32 bits. Using a REX Prefix in the form of REX.R permits access to addi-tional registers (R8-15). Using REX Prefix in the form of REX.W promotes operation to 64-bits.

ADOX executes normally either inside or outside a transaction region.

Note: ADOX defines the CF and OF flags differently than the ADD/ADC instructions as defined in Intel(R) 64 and IA-32 Architectures Software Developer's Manual, Volume 2A.

Operation

IF OperandSize is 64-bit
    THEN OF:DEST[63:0] <- DEST[63:0] + SRC[63:0] + OF;
    ELSE OF:DEST[31:0] <- DEST[31:0] + SRC[31:0] + OF;
FI;

Flags Affected

OF is updated based on result. CF, SF, ZF, AF and PF flags are unmodified.

Intel C/C++ Compiler Intrinsic Equivalent

unsigned char _addcarryx_u32(unsigned char c_in, unsigned int src1,
                             unsigned int src2, unsigned int *sum_out);
unsigned char _addcarryx_u64(unsigned char c_in, unsigned __int64 src1,
                             unsigned __int64 src2, unsigned __int64 *sum_out);

SIMD Floating-Point Exceptions

None

Protected Mode Exceptions

#UD

  • If the LOCK prefix is used.

  • If CPUID.(EAX=07H, ECX=0H):EBX.ADX[bit 19] = 0.

#SS(0)

  • For an illegal address in the SS segment.

#GP(0)

  • For an illegal memory operand effective address in the CS, DS, ES, FS or GS segments.

  • If the DS, ES, FS, or GS register is used to access memory and it contains a null segment selector.

#PF(fault-code)

  • For a page fault.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

Real-Address Mode Exceptions

#UD

  • If the LOCK prefix is used.

  • If CPUID.(EAX=07H, ECX=0H):EBX.ADX[bit 19] = 0.

#SS(0)

  • For an illegal address in the SS segment.

#GP(0)

  • If any part of the operand lies outside the effective address space from 0 to FFFFH.

Virtual-8086 Mode Exceptions

#UD

  • If the LOCK prefix is used.

  • If CPUID.(EAX=07H, ECX=0H):EBX.ADX[bit 19] = 0.

#SS(0)

  • For an illegal address in the SS segment.

#GP(0)

  • If any part of the operand lies outside the effective address space from 0 to FFFFH.

#PF(fault-code)

  • For a page fault.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

Compatibility Mode Exceptions

Same exceptions as in protected mode.

64-Bit Mode Exceptions

#UD

  • If the LOCK prefix is used.

  • If CPUID.(EAX=07H, ECX=0H):EBX.ADX[bit 19] = 0.

#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)

  • For a page fault.

#AC(0)

  • If alignment checking is enabled and an unaligned memory reference is made while the current privilege level is 3.

첫 댓글을 달아주세요!
프로필 사진 없음
강좌에 관련 없이 궁금한 내용은 여기를 사용해주세요