130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
#include "stddef.h"
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#include "console.h"
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/** @file */
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#include "bios.h"
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static struct console_driver console_drivers[0] __table_start ( console );
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static struct console_driver console_drivers_end[0] __table_end ( console );
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/**
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* Write a single character to each console device.
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*
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* @v character Character to be written
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* @ret None -
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* @err None -
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*
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* The character is written out to all enabled console devices, using
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* each device's console_driver::putchar() method.
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*
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*/
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void putchar ( int character ) {
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struct console_driver *console;
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/* Automatic LF -> CR,LF translation */
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if ( character == '\n' )
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putchar ( '\r' );
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for ( console = console_drivers; console < console_drivers_end ;
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console++ ) {
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if ( ( ! console->disabled ) && console->putchar )
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console->putchar ( character );
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}
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}
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/**
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* Check to see if any input is available on any console.
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*
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* @v None -
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* @ret console Console device that has input available, if any.
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* @ret NULL No console device has input available.
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* @err None -
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*
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* All enabled console devices are checked once for available input
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* using each device's console_driver::iskey() method. The first
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* console device that has available input will be returned, if any.
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*
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*/
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static struct console_driver * has_input ( void ) {
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struct console_driver *console;
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for ( console = console_drivers; console < console_drivers_end ;
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console++ ) {
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if ( ( ! console->disabled ) && console->iskey ) {
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if ( console->iskey () )
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return console;
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}
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}
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return NULL;
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}
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/**
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* Read a single character from any console.
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*
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* @v None -
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* @ret character Character read from a console.
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* @err None -
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*
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* A character will be read from the first enabled console device that
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* has input available using that console's console_driver::getchar()
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* method. If no console has input available to be read, this method
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* will block. To perform a non-blocking read, use something like
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*
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* @code
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*
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* int key = iskey() ? getchar() : -1;
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*
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* @endcode
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*
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* The character read will not be echoed back to any console.
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*
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* @bug We need a cleaner way to pick up cpu_nap(). It makes a
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* real-mode call, and so we don't want to use it with LinuxBIOS.
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*
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*/
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int getchar ( void ) {
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struct console_driver *console;
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int character = 256;
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while ( character == 256 ) {
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/* Doze for a while (until the next interrupt). This works
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* fine, because the keyboard is interrupt-driven, and the
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* timer interrupt (approx. every 50msec) takes care of the
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* serial port, which is read by polling. This reduces the
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* power dissipation of a modern CPU considerably, and also
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* makes Etherboot waiting for user interaction waste a lot
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* less CPU time in a VMware session.
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*/
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cpu_nap();
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console = has_input();
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if ( console && console->getchar )
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character = console->getchar ();
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}
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/* CR -> LF translation */
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if ( character == '\r' )
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character = '\n';
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return character;
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}
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/** Check for available input on any console.
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*
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* @v None -
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* @ret True Input is available on a console
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* @ret False Input is not available on any console
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* @err None -
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*
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* All enabled console devices are checked once for available input
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* using each device's console_driver::iskey() method. If any console
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* device has input available, this call will return True. If this
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* call returns True, you can then safely call getchar() without
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* blocking.
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*
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*/
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int iskey ( void ) {
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return has_input() ? 1 : 0;
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}
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