en:docs:bios:api:int14:01

Note: This IBM PC BIOS API call is for DOS/Win16 personality only. Use Family API for portability.

Note: osFree Macro Library provides macros for most of functions

2022/03/13 05:41 · prokushev · 0 Comments

Int 14H, AH=01H

Version

IBM 5150 and higher

Brief

Write character to port

Family API

Input

  • AH = 01h
  • AL = character to write
  • DX = port number (00h-03h) (04h-43h for Digiboard XAPCM232.SYS)

Return

  • AH bit 7 clear if successful
  • AH bit 7 set on error
  • AH bits 6-0 = port status (see #00304)

Macro

INCLUDE BIOS.INC
 
@AuxSendChar 0, 'A'

Notes

  • various network and serial-port drivers support the standard BIOS functions with interrupt-driven I/O instead of the BIOS's polled I/O
  • the 1993/04/08 Compaq system ROM uses only the low two bits of DX

Note