aboutsummaryrefslogtreecommitdiffstats
path: root/sample/hello2.c
blob: e89201128dc27e5eea9f8486a043825e9d33f417 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2002-2008 H. Peter Anvin - All Rights Reserved
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
 *   Boston MA 02111-1307, USA; either version 2 of the License, or
 *   (at your option) any later version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * hello2.c
 *
 * Simple COM32 image
 *
 * This version shows how to use the bounce buffer for data transfer
 * to the BIOS or COMBOOT system calls.
 */

#include <com32.h>

#define NULL ((void *)0)

static inline void memset(void *buf, int ch, unsigned int len)
{
    asm volatile ("cld; rep; stosb":"+D" (buf), "+c"(len):"a"(ch):"memory");
}

static void strcpy(char *dst, const char *src)
{
    while (*src)
	*dst++ = *src++;

    *dst = '\0';
}

static void writemsg(const char *msg)
{
    com32sys_t inreg;

    memset(&inreg, 0, sizeof inreg);

    strcpy(__com32.cs_bounce, msg);
    inreg.eax.w[0] = 0x0002;	/* Write string */
    inreg.ebx.w[0] = OFFS(__com32.cs_bounce);
    inreg.es = SEG(__com32.cs_bounce);
    __com32.cs_intcall(0x22, &inreg, NULL);
};

int __start(void)
{
    writemsg("Hello, World!\r\n" "cmdline = ");
    writemsg(__com32.cs_cmdline);
    writemsg("\r\n");
    return 0;
}