모두의 코드
OUT (Intel x86/64 assembly instruction)
OUT
Output to Port
참고 사항
아래 표를 해석하는 방법은 x86-64 명령어 레퍼런스 읽는 법 글을 참조하시기 바랍니다.
Opcode* | Instruction | Op/ | 64-Bit | Compat/ | Description |
---|---|---|---|---|---|
E6 ib | OUT imm8 AL | I | Valid | Valid | Output byte in AL to I/O port address imm8. |
E7 ib | OUT imm8 AX | I | Valid | Valid | Output word in AX to I/O port address imm8. |
E7 ib | OUT imm8 EAX | I | Valid | Valid | Output doubleword in EAX to I/O port address imm8. |
EE | OUT DX AL | NP | Valid | Valid | Output byte in AL to I/O port address in DX. |
EF | OUT DX AX | NP | Valid | Valid | Output word in AX to I/O port address in DX. |
EF | OUT DX EAX | NP | Valid | Valid | Output doubleword in EAX to I/O port address in DX. |
* See IA-32 Architecture Compatibility section below
Instruction Operand Encoding
Op/En | Operand 1 | Operand 2 | Operand 3 | Operand 4 |
---|---|---|---|---|
I | imm8 | NA | NA | NA |
NP | NA | NA | NA | NA |
Description
Copies the value from the second operand (source operand) to the I/O port specified with the destination operand (first operand). The source operand can be register AL, AX, or EAX, depending on the size of the port being accessed (8, 16, or 32 bits, respectively); the destination operand can be a byte-immediate or the DX register. Using a byte immediate allows I/O port addresses 0 to 255 to be accessed; using the DX register as a source operand allows I/O ports from 0 to 65,535 to be accessed.
The size of the I/O port being accessed is determined by the opcode for an 8-bit I/O port or by the operand-size attribute of the instruction for a 16- or 32-bit I/O port.
At the machine code level, I/O instructions are shorter when accessing 8-bit I/O ports. Here, the upper eight bits of the port address will be 0.
This instruction is only useful for accessing I/O ports located in the processor's I/O address space. See Chapter 18, "Input/Output," in the Intel(R) 64 and IA-32 Architectures Software Developer's Manual, Volume 1, for more infor-mation on accessing I/O ports in the I/O address space.
This instruction's operation is the same in non-64-bit modes and 64-bit mode.
IA-32 Architecture Compatibility
After executing an OUT instruction, the Pentium(R) processor ensures that the EWBE# pin has been sampled active before it begins to execute the next instruction. (Note that the instruction can be prefetched if EWBE# is not active, but it will not be executed until the EWBE# pin is sampled active.) Only the Pentium processor family has the EWBE# pin.
Operation
IF ((PE = 1) and ((CPL > IOPL) or (VM = 1))) THEN (* Protected mode with CPL > IOPL or virtual-8086 mode *) IF (Any I/O Permission Bit for I/O port being accessed = 1) THEN (* I/O operation is not allowed *) #GP(0); ELSE ( * I/O operation is allowed *) DEST <- SRC; (* Writes to selected I/O port *) FI; ELSE (Real Mode or Protected Mode with CPL <= IOPL *) DEST <- SRC; (* Writes to selected I/O port *) FI;
Flags Affected
None
Protected Mode Exceptions
#GP(0)
If the CPL is greater than (has less privilege) the I/O privilege level (IOPL) and any of the corresponding I/O permission bits in TSS for the I/O port being accessed is 1.
#UD
If the LOCK prefix is used.
Real-Address Mode Exceptions
#UD
If the LOCK prefix is used.
Virtual-8086 Mode Exceptions
#GP(0)
If any of the I/O permission bits in the TSS for the I/O port being accessed is 1.
#PF(fault-code)
If a page fault occurs.
#UD
If the LOCK prefix is used.
Compatibility Mode Exceptions
Same as protected mode exceptions.
64-Bit Mode Exceptions
Same as protected mode exceptions.
댓글을 불러오는 중입니다..