Assembler:Commands:IN - Revision history

TheyCallMeTim13 at 02:55, 25 January 2018

2018-01-25T02:55:48Z

TheyCallMeTim13 at 02:55, 25 January 2018

2018-01-25T02:55:24Z

TheyCallMeTim13 at 23:42, 24 January 2018

2018-01-24T23:42:22Z

TheyCallMeTim13: Created page with 'Category:Assembler '''command''' in ''destination'', ''source'' Input from Port. Copies the value from the I/O port specified with the second operand (source operand) to the…'

2018-01-22T22:41:32Z

Created page with 'Category:Assembler '''command''' in ''destination'', ''source'' Input from Port. Copies the value from the I/O port specified with the second operand (source operand) to the…'

New page

[[Category:Assembler]]
'''command''' in ''destination'', ''source''

Input from Port. Copies the value from the I/O port specified with the second operand (source operand) to the destination operand (first operand).

<div style="padding:2px;border:1px dashed #2f6fab;background-color:#f4f4f4;">
Copies the value from the I/O port specified with the second operand (source operand) to the destination operand (first operand). The source operand can be a byte-immediate or the DX register; the destination operand can be register AL, AX, or EAX, depending on the size of the port being accessed (8, 16, or 32 bits, respectively). Using the DX register as a source operand allows I/O port addresses from 0 to 65,535 to be accessed; using a byte immediate allows I/O port addresses 0 to 255 to be accessed.

When accessing an 8-bit I/O port, the opcode determines the port size; when accessing a 16- and 32-bit I/O port, the operand-size attribute determines the port size.

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 13, Input/Output, in the IA-32 Intel Architecture Software Developer's Manual, Volume 1, for more information on accessing I/O ports in the I/O address space.

[http://c9x.me/x86/html/file_module_x86_id_139.html c9x.me/x86/html/file_module_x86_id_139.html]
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=== Command Parameters ===
{|width="85%" cellpadding="10%" cellpadding="5%" cellspacing="0" border="0"
!align="left"|Parameter
!style="width: 80%;background-color:white;" align="left"|Description
|-
|destination
|The destination of the byte(s) read
|-
|source
|The I/O port number to read
|}

{{AssemblerCommandSeeAlso}}

{{Template:AssemblerCommandExternalLinks}}

@@ Line 14: / Line 14: @@
 This instruction is only useful for accessing I/O ports located in the processor's I/O address space.
-For more information on accessing I/O ports in the I/O address space: [https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-vol-1-manual.pdf 64-ia-32-architectures-software-developer-vol-1-manual.pdf]
+For more information on accessing I/O ports in the I/O address space, see: [https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-vol-1-manual.pdf 64-ia-32-architectures-software-developer-vol-1-manual.pdf]
 [http://c9x.me/x86/html/file_module_x86_id_139.html c9x.me/x86/html/file_module_x86_id_139.html]

@@ Line 12: / Line 12: @@
 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 13, Input/Output, in the IA-32 Intel Architecture Software Developer's Manual, Volume 1, for more information on accessing I/O ports in the I/O address space. [https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-software-developer-vol-1-manual.pdf 64-ia-32-architectures-software-developer-vol-1-manual.pdf]
+This instruction is only useful for accessing I/O ports located in the processor's I/O address space.
 [http://c9x.me/x86/html/file_module_x86_id_139.html c9x.me/x86/html/file_module_x86_id_139.html]