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#include "msdos.v"
#include "msdos16.v"
#define DOS_SYSID 0x03
#define DOS_SECT 0x0B
#define DOS_CLUST 0x0D
#define DOS_RESV 0x0E
#define DOS_NFAT 0x10
#define DOS_NROOT 0x11
#define DOS_MAXSECT 0x13
#define DOS_MEDIA 0x15
#define DOS_FATLEN 0x16
#define DOS_SPT 0x18
#define DOS_HEADS 0x1A
#define DOS_HIDDEN 0x1C
#define DOS4_MAXSECT 0x20
#define DOS4_PHY_DRIVE 0x24
#define DOS4_SERIAL 0x27
#define DOS4_LABEL 0x2B
#define DOS4_FATTYPE 0x36
unsigned char buffer[1024];
int drive = 0;
main(argc, argv)
int argc;
char ** argv;
{
int tries, rv, i;
if( argc > 1 )
{
static char * s = "Usage: lsys [a:]\n";
if( argc == 2 && argv[1][1] == ':' && argv[1][2] <= ' ' )
{
if( argv[1][0] == 'a' || argv[1][0] == 'A' )
drive = 0;
else if( argv[1][0] == 'b' || argv[1][0] == 'B' )
drive = 1;
else
fatal(s);
}
else
fatal(s);
}
for(tries=0; tries<6; tries++)
if( (rv = dos_sect_read(drive, 0, 0, 1, buffer)) == 0 )
break;
if( rv == 0 )
for(tries=0; tries<6; tries++)
if( (rv = dos_sect_read(drive, 0, 0, 2, buffer+512)) == 0 )
break;
if( rv ) fatal("Cannot read bootsector");
if( buffer[DOS_MEDIA] != buffer[512] ||
buffer[DOS_MEDIA] < 0xF0 ||
buffer[DOS_NFAT] > 2 ||
buffer[DOS_SECT+1] != 2 )
fatal("Floppy has invalid format");
if( memcmp(buffer+DOS4_FATTYPE, "FAT16", 5) )
{
for(i=0; i<msdos_dosfs_stat - msdos_start; i++)
buffer[i] = msdos_data[i];
for(i=msdos_codestart - msdos_start; i<512; i++)
buffer[i] = msdos_data[i];
}
else
{
for(i=0; i<msdos16_dosfs_stat - msdos_start; i++)
buffer[i] = msdos16_data[i];
for(i=msdos_codestart - msdos_start; i<512; i++)
buffer[i] = msdos16_data[i];
}
for(tries=0; tries<6; tries++)
if( (rv = dos_sect_write(drive, 0, 0, 1, buffer)) == 0 )
break;
if( rv ) fatal("Cannot write bootsector");
write(0, "Wrote bootsector\r\n", 18);
return 0;
}
fatal(str)
{
write(0, str, strlen(str));
write(0, "\r\n", 2);
exit(1);
}
dos_sect_write(drv, track, head, sector, loadaddr)
{
#asm
push bp
mov bp,sp
push ds
pop es
mov dh,[bp+2+_dos_sect_write.head]
mov dl,[bp+2+_dos_sect_write.drv]
mov cl,[bp+2+_dos_sect_write.sector]
mov ch,[bp+2+_dos_sect_write.track]
mov bx,[bp+2+_dos_sect_write.loadaddr]
mov ax,#$0301
int $13
jc write_err
mov ax,#0
write_err:
pop bp
#endasm
}
dos_sect_read(drv, track, head, sector, loadaddr)
{
#asm
push bp
mov bp,sp
push ds
pop es
mov dh,[bp+2+_dos_sect_read.head]
mov dl,[bp+2+_dos_sect_read.drv]
mov cl,[bp+2+_dos_sect_read.sector]
mov ch,[bp+2+_dos_sect_read.track]
mov bx,[bp+2+_dos_sect_read.loadaddr]
mov ax,#$0201
int $13
jc read_err
mov ax,#0
read_err:
pop bp
#endasm
}
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