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Fix comconsole mode. The int 0x14 read and status commands were reversed.

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Also, make sure we set %dx each time around otherwise the commands
suddenly start trying to work on things like com92 instead of com1.
Make sure comc_init() is only run once.
Cosmetic change to init-time character eater.
This commit is contained in:
Peter Wemm 1998-10-11 10:05:13 +00:00
parent 1206a4f594
commit a1c1935fa8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=40211
1 changed files with 21 additions and 7 deletions
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28
sys/boot/i386/libi386/comconsole.c
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@ -24,7 +24,7 @@
*
* From Id: probe_keyboard.c,v 1.13 1997/06/09 05:10:55 bde Exp
*
* $Id: comconsole.c,v 1.2 1998/09/17 23:52:09 msmith Exp $
* $Id: comconsole.c,v 1.3 1998/10/02 16:32:45 msmith Exp $
*/
#include <stand.h>
@ -38,6 +38,8 @@ static void comc_putchar(int c);
static int comc_getchar(void);
static int comc_ischar(void);
static int comc_started;
struct console comconsole = {
"comconsole",
"BIOS serial port",
@ -61,12 +63,21 @@ comc_probe(struct console *cp)
static int
comc_init(int arg)
{
v86.ctl = V86_FLAGS;
int i;
if (comc_started && arg == 0)
return 0;
comc_started = 1;
v86.ctl = 0;
v86.addr = 0x14;
v86.eax = 0xe3; /* 9600N81 */
v86.edx = BIOS_COMPORT; /* XXX take as arg, or use env var? */
v86int();
return(v86.efl & 1);
for(i = 0; i < 10 && comc_ischar(); i++)
(void)comc_getchar();
return(0);
}
static void
@ -74,7 +85,8 @@ comc_putchar(int c)
{
v86.ctl = 0;
v86.addr = 0x14;
v86.eax = 0x100 | c;
v86.eax = 0x100 | c; /* Function 1 = write */
v86.edx = BIOS_COMPORT; /* XXX take as arg, or use env var? */
v86int();
}
@ -84,7 +96,8 @@ comc_getchar(void)
if (comc_ischar()) {
v86.ctl = 0;
v86.addr = 0x14;
v86.eax = 0x300;
v86.eax = 0x200; /* Function 2 = read */
v86.edx = BIOS_COMPORT; /* XXX take as arg, or use env var? */
v86int();
return(v86.eax & 0xff);
} else {
@ -97,7 +110,8 @@ comc_ischar(void)
{
v86.ctl = 0;
v86.addr = 0x14;
v86.eax = 0x200;
v86.eax = 0x300; /* Function 3 = status */
v86.edx = BIOS_COMPORT; /* XXX take as arg, or use env var? */
v86int();
return(v86.eax & 0x1);
return(v86.eax & 0x100); /* AH bit 1 is "receive data ready" */
}