minix/kernel/kprintf.c

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/*
* printf for the kernel
*
* Changes:
* Dec 10, 2004 kernel printing to circular buffer (Jorrit N. Herder)
*
* This file contains the routines that take care of kernel messages, i.e.,
* diagnostic output within the kernel. Kernel messages are not directly
* displayed on the console, because this must be done by the output driver.
* Instead, the kernel accumulates characters in a buffer and notifies the
* output driver when a new message is ready.
*/
#include "kernel.h"
#include "proc.h"
#include <signal.h>
#define printf kprintf
#include "../lib/sysutil/kprintf.c"
#define END_OF_KMESS 0
FORWARD _PROTOTYPE( void ser_putc, (char c));
/*===========================================================================*
* kputc *
*===========================================================================*/
PUBLIC void kputc(c)
int c; /* character to append */
{
/* Accumulate a single character for a kernel message. Send a notification
* to the output driver if an END_OF_KMESS is encountered.
*/
if (c != END_OF_KMESS) {
if (do_serial_debug)
ser_putc(c);
kmess.km_buf[kmess.km_next] = c; /* put normal char in buffer */
if (kmess.km_size < KMESS_BUF_SIZE)
kmess.km_size += 1;
kmess.km_next = (kmess.km_next + 1) % KMESS_BUF_SIZE;
} else {
int p, outprocs[] = OUTPUT_PROCS_ARRAY;
for(p = 0; outprocs[p] != NONE; p++) {
if(isokprocn(outprocs[p]) && !isemptyn(outprocs[p])) {
send_sig(outprocs[p], SIGKMESS);
}
}
}
}
#define COM1_BASE 0x3F8
#define COM1_THR (COM1_BASE + 0)
#define LSR_THRE 0x20
#define COM1_LSR (COM1_BASE + 5)
PRIVATE void ser_putc(char c)
{
int i;
int lsr, thr;
return;
lsr= COM1_LSR;
thr= COM1_THR;
for (i= 0; i<100000; i++)
{
if (inb(lsr) & LSR_THRE)
break;
}
outb(thr, c);
}