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#include "stddef.h"
#include "console.h"
#include <gpxe/process.h>
#include <gpxe/nap.h>
/** @file */
/**
* Write a single character to each console device.
*
* @v character Character to be written
* @ret None -
* @err None -
*
* The character is written out to all enabled console devices, using
* each device's console_driver::putchar() method.
*
*/
void putchar ( int character ) {
struct console_driver *console;
/* Automatic LF -> CR,LF translation */
if ( character == '\n' )
putchar ( '\r' );
for_each_table_entry ( console, CONSOLES ) {
if ( ( ! console->disabled ) && console->putchar )
console->putchar ( character );
}
}
/**
* Check to see if any input is available on any console.
*
* @v None -
* @ret console Console device that has input available, if any.
* @ret NULL No console device has input available.
* @err None -
*
* All enabled console devices are checked once for available input
* using each device's console_driver::iskey() method. The first
* console device that has available input will be returned, if any.
*
*/
static struct console_driver * has_input ( void ) {
struct console_driver *console;
for_each_table_entry ( console, CONSOLES ) {
if ( ( ! console->disabled ) && console->iskey ) {
if ( console->iskey () )
return console;
}
}
return NULL;
}
/**
* Read a single character from any console.
*
* @v None -
* @ret character Character read from a console.
* @err None -
*
* A character will be read from the first enabled console device that
* has input available using that console's console_driver::getchar()
* method. If no console has input available to be read, this method
* will block. To perform a non-blocking read, use something like
*
* @code
*
* int key = iskey() ? getchar() : -1;
*
* @endcode
*
* The character read will not be echoed back to any console.
*
*/
int getchar ( void ) {
struct console_driver *console;
int character;
while ( 1 ) {
console = has_input();
if ( console && console->getchar ) {
character = console->getchar ();
break;
}
/* Doze for a while (until the next interrupt). This works
* fine, because the keyboard is interrupt-driven, and the
* timer interrupt (approx. every 50msec) takes care of the
* serial port, which is read by polling. This reduces the
* power dissipation of a modern CPU considerably, and also
* makes Etherboot waiting for user interaction waste a lot
* less CPU time in a VMware session.
*/
cpu_nap();
/* Keep processing background tasks while we wait for
* input.
*/
step();
}
/* CR -> LF translation */
if ( character == '\r' )
character = '\n';
return character;
}
/** Check for available input on any console.
*
* @v None -
* @ret True Input is available on a console
* @ret False Input is not available on any console
* @err None -
*
* All enabled console devices are checked once for available input
* using each device's console_driver::iskey() method. If any console
* device has input available, this call will return True. If this
* call returns True, you can then safely call getchar() without
* blocking.
*
*/
int iskey ( void ) {
return has_input() ? 1 : 0;
}
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