Outils pour utilisateurs
back2root:ibm-pc-ms-dos:instr:in
Ceci est une ancienne révision du document !
IN
IN - Input Byte or Word From Port
A byte, word or dword is read from “port” and placed in AL, AX or EAX respectively. If the port number is in the range of 0-255 it can be specified as an immediate, otherwise the port number must be specified in DX. Valid port ranges on the PC are 0-1024, though values through 65535 may be specified and recognized by third party vendors and PS/2's.
Usage:
IN accum,port ;
Modifies flags:
none
| Clocks | Size | |||||
|---|---|---|---|---|---|---|
| Operands | 808x | 286 | 386 | 486 | Bytes | |
| none | 10/14 | 3 | 4 | 4 | 1 | |
| none (PM) | - | - | 4 | 3 | 1 | |
| 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 | 1 | 2-4 | (W88=13+EA) |
| reg,immed | 4 | 3 | 2 | 1 | 3-4 | |
| mem,immed | 17+EA | 7 | 7 | 3 | 3-6 | (W88=23+EA) |
| accum,immed | 4 | 3 | 2 | 1 | 2-3 | |
- 386+ protected mode timings depend on privilege levels.
| first number is the timing if: | CPL ¾ IOPL |
| second number is the timing if: | CPL > IOPL or in VM 86 mode (386) |
| CPL ‗ IOPL (486) | |
| third number is the timing when: | virtual mode on 486 processor |
- 486 virtual mode always requires 27 cycles
back2root/ibm-pc-ms-dos/instr/in.1677358638.txt.gz · Dernière modification : 2023/02/25 21:57 de frater
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