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This HTML version of the file intel.doc from the
PC Game Programmer's guide was produced by Zack T Smith. Fancy HTML modifications are copyright ©
2005 by Zack T Smith, all rights reserved.
This information is provided in the hope that it will be useful,
but without any warranty. It is provided AS-IS,
without even the implied warranty of fitness for a particular purpose.
O Instructions
OR - Inclusive Logical OR
Usage: OR dest,src
Modifies flags: CF OF PF SF ZF (AF undefined)
Logical inclusive OR of the two operands returning the result in
the destination. Any bit set in either operand will be set in the
destination.
Clocks Size
Operands 808x 286 386 486 Bytes
reg,reg 3 2 2 1 2
mem,reg 16+EA 7 7 3 2-4 (W88=24+EA)
reg,mem 9+EA 7 6 2 2-4 (W88=13+EA)
reg,immed 4 3 2 1 3-4
mem8,immed8 17+EA 7 7 3 3-6
mem16,immed16 25+EA 7 7 3 3-6
accum,immed 4 3 2 1 2-3
OUT - Output Data to Port
Usage: OUT port,accum
Modifies flags: None
Transfers byte in AL,word in AX or dword in EAX to the specified
hardware port address. If the port number is in the range of 0-255
it can be specified as an immediate. If greater than 255 then the
port number must be specified in DX. Since the PC only decodes 10
bits of the port address, values over 1023 can only be decoded by
third party vendor equipment and also map to the port range 0-1023.
Clocks Size
Operands 808x 286 386 486 Bytes
immed8,accum 10/14 3 10 16 2
immed8,accum (PM) - - 4/24 11/31/29 2
DX,accum 8/12 3 11 16 1
DX,accum (PM) - - 5/25 10/30/29 1
- 386+ protected mode timings depend on privilege levels.
first number is the timing when: CPL ≤ IOPL
second number is the timing when: CPL > IOPL
third number is the timing when: virtual mode on 486 processor
OUTS - Output String to Port (80188+)
Usage: OUTS port,src
OUTSB
OUTSW
OUTSD (386+)
Modifies flags: None
Transfers a byte, word or doubleword from "src" to the hardware
port specified in DX. For instructions with no operands the "src"
is located at DS:SI and SI is incremented or decremented by the
size of the operand or the size dictated by the instruction format.
When the Direction Flag is set SI is decremented, when clear, SI is
incremented. If the port number is in the range of 0-255 it can
be specified as an immediate. If greater than 255 then the port
number must be specified in DX. Since the PC only decodes 10 bits
of the port address, values over 1023 can only be decoded by third
party vendor equipment and also map to the port range 0-1023.
Clocks Size
Operands 808x 286 386 486 Bytes
port,src - 5 14 17 1
port,src (PM) - - 8/28 10/32/30 1
- 386+ protected mode timings depend on privilege levels.
first number is the timing when: CPL ≤ IOPL
second number is the timing when: CPL > IOPL
third number is the timing when: virtual mode on 486 processor
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