| 1 | #if (TRY_FLOPPY_FIRST > 0)
|
|---|
| 2 |
|
|---|
| 3 | /*
|
|---|
| 4 | * This program is free software; you can redistribute it and/or
|
|---|
| 5 | * modify it under the terms of the GNU General Public License as
|
|---|
| 6 | * published by the Free Software Foundation; either version 2, or (at
|
|---|
| 7 | * your option) any later version.
|
|---|
| 8 | */
|
|---|
| 9 |
|
|---|
| 10 | #include "etherboot.h"
|
|---|
| 11 |
|
|---|
| 12 | #define BOOTSECT ((char *)0x7C00)
|
|---|
| 13 | #define BOOTSIG ((unsigned short *)BOOTSECT)[0xFF]
|
|---|
| 14 | #define PARTTAB ((partentry *)(BOOTSECT+0x1BE))
|
|---|
| 15 |
|
|---|
| 16 | typedef struct partentry {
|
|---|
| 17 | unsigned char flags;
|
|---|
| 18 | unsigned char start_head;
|
|---|
| 19 | unsigned char start_sector;
|
|---|
| 20 | unsigned char start_cylinder;
|
|---|
| 21 | unsigned char type;
|
|---|
| 22 | unsigned char end_head;
|
|---|
| 23 | unsigned char end_sector;
|
|---|
| 24 | unsigned char end_cylinder;
|
|---|
| 25 | unsigned long offset;
|
|---|
| 26 | unsigned long length;
|
|---|
| 27 | } partentry;
|
|---|
| 28 |
|
|---|
| 29 | static unsigned int disk_read_retry(int dev,int c,int h,int s)
|
|---|
| 30 | {
|
|---|
| 31 | int retry = 3,rc;
|
|---|
| 32 |
|
|---|
| 33 | while (retry-- && (rc = pcbios_disk_read(dev,c,h,s,BOOTSECT)) != 0);
|
|---|
| 34 | if (BOOTSIG != 0xAA55) {
|
|---|
| 35 | printf("not a boot sector");
|
|---|
| 36 | return(0xFFFF); }
|
|---|
| 37 | return(rc);
|
|---|
| 38 | }
|
|---|
| 39 |
|
|---|
| 40 | int bootdisk(int dev,int part)
|
|---|
| 41 | {
|
|---|
| 42 | int rc;
|
|---|
| 43 |
|
|---|
| 44 | disk_init();
|
|---|
| 45 | if ((rc = disk_read_retry(dev,0,0,1)) != 0) {
|
|---|
| 46 | readerr:
|
|---|
| 47 | if (rc != 0xFFFF)
|
|---|
| 48 | printf("read error (%#hhX)",rc/256);
|
|---|
| 49 | return(0); }
|
|---|
| 50 | if (part) {
|
|---|
| 51 | partentry *ptr;
|
|---|
| 52 |
|
|---|
| 53 | if (part >= 5) {
|
|---|
| 54 | int i;
|
|---|
| 55 | for (i = 0, ptr = PARTTAB; ptr->type != 5; ptr++)
|
|---|
| 56 | if (++i == 4) {
|
|---|
| 57 | printf("partition not found");
|
|---|
| 58 | return(0); }
|
|---|
| 59 | if ((rc = disk_read_retry(dev,
|
|---|
| 60 | ptr->start_cylinder,
|
|---|
| 61 | ptr->start_head,
|
|---|
| 62 | ptr->start_sector)) != 0)
|
|---|
| 63 | goto readerr;
|
|---|
| 64 | part -= 4; }
|
|---|
| 65 | if (!(ptr = PARTTAB-1+part)->type) {
|
|---|
| 66 | printf("empty partition");
|
|---|
| 67 | return(0); }
|
|---|
| 68 | if ((rc = disk_read_retry(dev,
|
|---|
| 69 | ptr->start_cylinder,
|
|---|
| 70 | ptr->start_head,
|
|---|
| 71 | ptr->start_sector)) != 0)
|
|---|
| 72 | goto readerr; }
|
|---|
| 73 | cleanup();
|
|---|
| 74 | gateA20_unset();
|
|---|
| 75 | /* Set %edx to device number to emulate BIOS
|
|---|
| 76 | Fortunately %edx is not used after this */
|
|---|
| 77 | __asm__("movl %0,%%edx" : : "g" (dev));
|
|---|
| 78 | xstart((unsigned long)BOOTSECT, 0, 0);
|
|---|
| 79 | return(0);
|
|---|
| 80 | }
|
|---|
| 81 |
|
|---|
| 82 | #endif
|
|---|
| 83 |
|
|---|
| 84 | /*
|
|---|
| 85 | * Local variables:
|
|---|
| 86 | * c-basic-offset: 8
|
|---|
| 87 | * End:
|
|---|
| 88 | */
|
|---|
