mirror of https://github.com/FDOS/kernel.git
add initial tests for DOS absolute sector read/write
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KJD
parent
bdc2e068c4
commit
5406ba5a9b
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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typedef unsigned long uint32_t;
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typedef unsigned short uint16_t;
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typedef unsigned char uint8_t;
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void die(char *msg)
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{
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printf("%s\n", msg);
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exit(1);
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}
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/* Both traditional DOS and FAT32 DOS return this structure, but
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FAT32 return a lot more data, so make sure we have plenty of space */
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struct deviceparams {
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uint8_t specfunc;
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uint8_t devtype;
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uint16_t devattr;
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uint16_t cylinders;
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uint8_t mediatype;
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uint16_t bytespersec;
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uint8_t secperclust;
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uint16_t ressectors;
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uint8_t fats;
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uint16_t rootdirents;
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uint16_t sectors;
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uint8_t media;
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uint16_t fatsecs;
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uint16_t secpertrack;
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uint16_t heads;
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uint32_t hiddensecs;
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uint32_t hugesectors;
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uint8_t lotsofpadding[224];
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};
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void get_partition_offset(int drive)
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{
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static struct deviceparams dp;
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int err=0;
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printf("Getting drive info: int21h function 440Dh subfunction 0860h\n");
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dp.specfunc = 1; /* Get current information */
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__asm {
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mov ax, 0x440d
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mov bx, drive
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mov cx, 0x0860
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mov dx, offset dp
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int 0x21
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mov ax, 0
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adc ax, 0
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mov err, ax
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}
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if (!err)
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{
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printf("Partition Offset = %02lXh [c=%02u,h=%02u,s=%2u]\n", dp.hiddensecs, dp.cylinders, dp.heads, dp.secpertrack);
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printf("FAT32 version 4860h to compare\n");
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}
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else
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printf("Original version failed, checking FAT32 version using 4860h\n");
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__asm {
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mov ax, 0x440d
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mov bx, drive
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mov cx, 0x4860
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mov dx, offset dp
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int 0x21
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mov ax, 0
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adc ax, 0
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mov err, ax
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}
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if (!err)
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{
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printf("Partition Offset = %02lXh\n", dp.hiddensecs);
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return;
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}
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else
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printf("FAT32 version failed.\n");
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}
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struct rwblock {
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uint8_t special;
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uint16_t head;
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uint16_t cylinder;
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uint16_t firstsector;
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uint16_t sectors;
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uint16_t bufferoffset;
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uint16_t bufferseg;
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};
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static struct rwblock mbr = {
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.special = 0,
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.head = 0,
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.cylinder = 0, /* 5265, 3fh */
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.firstsector = 0, /* MS-DOS, unlike the BIOS, zero-base sectors */
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.sectors = 1,
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.bufferoffset = 0,
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.bufferseg = 0
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};
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void read_mbr(int drive, const void *buf)
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{
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uint8_t err=0;
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uint16_t ds_seg=0;
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//printf("read_mbr(%c:,%p)", 'a'+drive-1, buf);
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mbr.bufferoffset = (unsigned short)buf;
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__asm {
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push ds
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pop ax
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mov ds_seg, ax
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}
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mbr.bufferseg = ds_seg;
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//printf("DS = %04Xh\n", ds_seg);
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__asm {
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mov ax, 0x440d
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mov bx, drive
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mov cx, 0x0861
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mov dx, offset mbr
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int 0x21
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mov ax, 0
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adc ax, 0
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mov err, al
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}
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if (!err) {
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//printf("Success reading MBR\n\n");
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return;
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}
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__asm {
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mov ax, 0x440d
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mov bx, drive
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mov cx, 0x4861
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mov dx, offset mbr
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int 0x21
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mov ax, 0
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adc ax, 0
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mov err, al
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}
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if (!err) {
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//printf("Success reading FAT32 MBR\n\n");
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return;
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}
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printf("mbr read error");
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}
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int main(int argc, char *argv[])
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{
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unsigned int c,h,s;
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static uint8_t buf[1024];
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unsigned drive = (unsigned)(argv[1][0]); /* a=1,b=2,... */
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drive = drive-'a'+1;
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printf("Query drive %c:\n", 'a'+drive-1);
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get_partition_offset(drive);
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read_mbr(drive, buf);
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printf("MBR: %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh\n",
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((const uint8_t *)buf)[0],
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((const uint8_t *)buf)[1],
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((const uint8_t *)buf)[2],
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((const uint8_t *)buf)[3],
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((const uint8_t *)buf)[4],
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((const uint8_t *)buf)[5],
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((const uint8_t *)buf)[6],
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((const uint8_t *)buf)[7]);
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printf("Finding drive\n");
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for (c = 1024; c <= 5265; c++) {
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for (h = 0; h < 255; h++)
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for (s = 0; s <= 63; s++)
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{
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mbr.cylinder = c;
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mbr.head =h;
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mbr.sectors=s;
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read_mbr(drive, buf);
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if (buf[0] != 0) {
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printf("Found at %u,%u,%u\n", c,h,s);
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printf("MBR: %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh %02Xh\n",
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((const uint8_t *)buf)[0],
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((const uint8_t *)buf)[1],
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((const uint8_t *)buf)[2],
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((const uint8_t *)buf)[3],
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((const uint8_t *)buf)[4],
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((const uint8_t *)buf)[5],
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((const uint8_t *)buf)[6],
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((const uint8_t *)buf)[7]);
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exit(0);
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}
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}
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printf("c=%u,", c); fflush(NULL);
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}
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return 0;
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}
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@ -0,0 +1,2 @@
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@ECHO OFF
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wcl -e3-we-wx-zq-os-s-zp1-mt-bt=DOS absread.c
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