diff options
Diffstat (limited to 'sys/i386/boot/biosboot/io.c')
| -rw-r--r-- | sys/i386/boot/biosboot/io.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/sys/i386/boot/biosboot/io.c b/sys/i386/boot/biosboot/io.c index 5c460d9..ce2b1fe 100644 --- a/sys/i386/boot/biosboot/io.c +++ b/sys/i386/boot/biosboot/io.c @@ -25,7 +25,7 @@ * the rights to redistribute these changes. * * from: Mach, Revision 2.2 92/04/04 11:35:57 rpd - * $Id: io.c,v 1.7 1994/09/16 13:33:17 davidg Exp $ + * $Id: io.c,v 1.8 1994/09/18 07:39:55 swallace Exp $ */ #include <machine/cpufunc.h> @@ -139,9 +139,20 @@ getchar() } #if BOOTWAIT -spinwait(i) -int i; +/* + * This routine uses an inb to an unused port, the time to execute that + * inb is approximately 1.25uS. This value is pretty constant across + * all CPU's and all buses, with the exception of some PCI implentations + * that do not forward this I/O adress to the ISA bus as they know it + * is not a valid ISA bus address, those machines execute this inb in + * 60 nS :-(. + * + * XXX we need to use BIOS timer calls or something more reliable to + * produce timeouts in the boot code. + */ +delay1ms() { + int i = 800; while (--i >= 0) (void)inb(0x84); } @@ -154,7 +165,7 @@ char *buf; char *ptr=buf; #if BOOTWAIT - for (i = BOOTWAIT; i>0; spinwait(10000),i--) + for (i = BOOTWAIT; i>0; delay1ms(),i--) #endif if (ischar()) for (;;) |
