693d05b755
* Add gitattributes to handle line endings. * Import the unmodified LTEMM source. From https://www.lo-tech.co.uk/wiki/LTEMM.EXE. * Add DOSBox and TASM for build. * Add build script for LTEMM. * Modity LTEMM driver for XTMax. * Import the unmodified SDPP source. From https://forum.vcfed.org/index.php?threads/sd-card-to-parallel-port-driver-for-msdos-ver-1-1.42008/. * Add Borland C++ 3.1 (Minimal) for build. * Add build script for SDPP. * Modify SDPP driver for XTMax. * Commit pre-built binaries for LTEMM and SDPP. * Reorganize the drivers into a new folder.
237 lines
10 KiB
C
237 lines
10 KiB
C
/* sd.c */
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/* */
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/* Copyright (C) 1994 by Robert Armstrong */
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/* */
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/* This program is free software; you can redistribute it and/or modify */
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/* it under the terms of the GNU General Public License as published by */
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/* the Free Software Foundation; either version 2 of the License, or */
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/* (at your option) any later version. */
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/* */
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/* This program is distributed in the hope that it will be useful, but */
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/* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANT- */
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/* ABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General */
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/* Public License for more details. */
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/* */
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/* You should have received a copy of the GNU General Public License */
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/* along with this program; if not, visit the website of the Free */
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/* Software Foundation, Inc., www.gnu.org. */
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/* */
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/* */
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/* The functions provided are: */
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/* */
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/* SDInitialize - establish two way communications with the drive */
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/* SDRead - read one 512 byte logical block from the tape */
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/* SDWrite - write one 512 byte logical block to the tape */
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/* SDMediaCheck - see if card detect has changed */
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/* */
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/* Normally the SDInitialize routine would be called */
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/* during the DOS device driver initialization, and then the SDRead and */
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/* */
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#include <stdio.h> /* needed for NULL, etc */
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#include <mem.h> /* memset, memcopy, etc */
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#include "standard.h" /* all definitions for this project */
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#include "sd.h" /* device protocol and data defintions */
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#include "diskio.h" /* stuff from sdmm.c module */
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#include "driver.h"
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#include "cprint.h"
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DWORD partition_offset = 0;
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/* FatFs refers the members in the FAT structures as byte array instead of
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/ structure member because the structure is not binary compatible between
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/ different platforms */
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#define BS_jmpBoot 0 /* Jump instruction (3) */
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#define BS_OEMName 3 /* OEM name (8) */
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#define BPB_BytsPerSec 11 /* Sector size [byte] (2) */
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#define BPB_SecPerClus 13 /* Cluster size [sector] (1) */
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#define BPB_RsvdSecCnt 14 /* Size of reserved area [sector] (2) */
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#define BPB_NumFATs 16 /* Number of FAT copies (1) */
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#define BPB_RootEntCnt 17 /* Number of root directory entries for FAT12/16 (2) */
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#define BPB_TotSec16 19 /* Volume size [sector] (2) */
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#define BPB_Media 21 /* Media descriptor (1) */
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#define BPB_FATSz16 22 /* FAT size [sector] (2) */
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#define BPB_SecPerTrk 24 /* Track size [sector] (2) */
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#define BPB_NumHeads 26 /* Number of heads (2) */
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#define BPB_HiddSec 28 /* Number of special hidden sectors (4) */
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#define BPB_TotSec32 32 /* Volume size [sector] (4) */
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#define BS_DrvNum 36 /* Physical drive number (2) */
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#define BS_BootSig 38 /* Extended boot signature (1) */
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#define BS_VolID 39 /* Volume serial number (4) */
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#define BS_VolLab 43 /* Volume label (8) */
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#define BS_FilSysType 54 /* File system type (1) */
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#define BPB_FATSz32 36 /* FAT size [sector] (4) */
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#define BPB_ExtFlags 40 /* Extended flags (2) */
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#define BPB_FSVer 42 /* File system version (2) */
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#define BPB_RootClus 44 /* Root directory first cluster (4) */
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#define BPB_FSInfo 48 /* Offset of FSINFO sector (2) */
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#define BPB_BkBootSec 50 /* Offset of backup boot sector (2) */
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#define BS_DrvNum32 64 /* Physical drive number (2) */
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#define BS_BootSig32 66 /* Extended boot signature (1) */
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#define BS_VolID32 67 /* Volume serial number (4) */
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#define BS_VolLab32 71 /* Volume label (8) */
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#define BS_FilSysType32 82 /* File system type (1) */
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#define FSI_LeadSig 0 /* FSI: Leading signature (4) */
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#define FSI_StrucSig 484 /* FSI: Structure signature (4) */
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#define FSI_Free_Count 488 /* FSI: Number of free clusters (4) */
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#define FSI_Nxt_Free 492 /* FSI: Last allocated cluster (4) */
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#define MBR_Table 446 /* MBR: Partition table offset (2) */
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#define SZ_PTE 16 /* MBR: Size of a partition table entry */
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#define BS_55AA 510 /* Boot sector signature (2) */
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BYTE local_buffer[BLOCKSIZE];
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#define LD_WORD(x) *((WORD *)(BYTE *)(x))
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#define LD_DWORD(x) *((DWORD *)(BYTE *)(x))
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/*-----------------------------------------------------------------------*/
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/* Load a sector and check if it is an FAT boot sector */
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/*-----------------------------------------------------------------------*/
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static
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BYTE check_fs (BYTE unit,
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/* 0:FAT boor sector, 1:Valid boor sector but not FAT, */
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/* 2:Not a boot sector, 3:Disk error */
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DWORD sect /* Sector# (lba) to check if it is an FAT boot record or not */
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)
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{
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if (disk_read (unit, local_buffer, sect, 1) != RES_OK)
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return 3;
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if (LD_WORD(&local_buffer[BS_55AA]) != 0xAA55) /* Check boot record signature (always placed at offset 510 even if the sector size is >512) */
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return 2;
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if ((LD_DWORD(&local_buffer[BS_FilSysType]) & 0xFFFFFF) == 0x544146) /* Check "FAT" string */
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return 0;
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if ((LD_DWORD(&local_buffer[BS_FilSysType32]) & 0xFFFFFF) == 0x544146) /* Check "FAT" string */
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return 0;
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return 1;
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}
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/*-----------------------------------------------------------------------*/
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/* Find logical drive and check if the volume is mounted */
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/*-----------------------------------------------------------------------*/
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static
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int find_volume (
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BYTE unit,
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BYTE partno,
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bpb_t *bpb
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)
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{
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BYTE fmt;
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DSTATUS stat;
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WORD secsize;
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DWORD bsect;
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stat = disk_status(unit);
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if (!(stat & STA_NOINIT)) { /* and the physical drive is kept initialized */
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return 0; /* The file system object is valid */
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}
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/* The file system object is not valid. */
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/* Following code attempts to mount the volume. (analyze BPB and initialize the fs object) */
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stat = disk_initialize(unit); /* Initialize the physical drive */
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if (stat & STA_NOINIT) /* Check if the initialization succeeded */
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return -1; /* Failed to initialize due to no medium or hard error */
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/* Find an FAT partition on the drive. Supports only generic partitioning, FDISK and SFD. */
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bsect = 0;
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fmt = check_fs(unit, bsect); /* Load sector 0 and check if it is an FAT boot sector as SFD */
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if (fmt == 1 || (!fmt && (partno))) { /* Not an FAT boot sector or forced partition number */
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UINT i;
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DWORD br[4];
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for (i = 0; i < 4; i++) { /* Get partition offset */
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BYTE *pt = &local_buffer[MBR_Table + i * SZ_PTE];
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br[i] = pt[4] ? LD_DWORD(&pt[8]) : 0;
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}
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i = partno; /* Partition number: 0:auto, 1-4:forced */
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if (i) i--;
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do { /* Find an FAT volume */
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bsect = br[i];
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fmt = bsect ? check_fs(unit, bsect) : 2; /* Check the partition */
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} while (!partno && fmt && ++i < 4);
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}
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if (fmt == 3) return -2; /* An error occured in the disk I/O layer */
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if (fmt) return -3; /* No FAT volume is found */
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/* An FAT volume is found. Following code initializes the file system object */
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secsize = LD_WORD(local_buffer + BPB_BytsPerSec);
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if (secsize != BLOCKSIZE)
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return -3;
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bpb->sector_size = BLOCKSIZE;
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bpb->allocation_unit = local_buffer[BPB_SecPerClus]; /* Number of sectors per cluster */
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bpb->reserved_sectors = LD_WORD(local_buffer+BPB_RsvdSecCnt); /* Number of reserved sectors */
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if (!bpb->reserved_sectors) return -3; /* (Must not be 0) */
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bpb->fat_count = local_buffer[BPB_NumFATs]; /* Number of FAT copies */
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if (bpb->fat_count == 0)
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bpb->fat_count = 2;
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bpb->directory_size = LD_WORD(local_buffer+BPB_RootEntCnt);
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bpb->total_sectors = LD_WORD(local_buffer+BPB_TotSec16);
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if (!bpb->total_sectors)
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bpb->sector_count = LD_DWORD(local_buffer+BPB_TotSec32);
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else
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bpb->sector_count = bpb->total_sectors;
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bpb->media_descriptor = local_buffer[BPB_Media];
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bpb->fat_sectors = LD_WORD(local_buffer+BPB_FATSz16); /* Number of sectors per FAT */
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bpb->track_size = LD_WORD(local_buffer+BPB_SecPerTrk); /* Number of sectors per cluster */
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bpb->head_count = LD_WORD(local_buffer+BPB_NumHeads); /* Number of sectors per cluster */
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bpb->hidden_sectors = 1;
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partition_offset = bsect;
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return 0;
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}
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/* SDInitialize */
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PUBLIC BOOLEAN SDInitialize (BYTE unit, BYTE partno, bpb_t *bpb)
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{
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if (find_volume(unit,partno,bpb) < 0)
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return FALSE;
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return TRUE;
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}
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/* SDMediaCheck */
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PUBLIC BOOLEAN SDMediaCheck (BYTE unit)
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{
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return (disk_result(unit) == RES_OK) ? FALSE : TRUE;
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}
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/* SDRead */
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/* IMPORTANT! Blocks are always 512 bytes! Never more, never less. */
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/* */
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/* INPUTS: */
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/* unit - selects tape drive 0 (left) or 1 (right) */
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/* lbn - logical block number to be read [0..511] */
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/* buffer - address of 512 bytes to receive the data read */
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/* */
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/* RETURNS: operation status as reported by the TU58 */
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/* */
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PUBLIC int SDRead (WORD unit, DWORD lbn, BYTE far *buffer, WORD count)
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{
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return disk_read (unit, buffer, lbn + partition_offset, count);
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}
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/* SDWrite */
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/* IMPORTANT! Blocks are always 512 bytes! Never more, never less. */
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/* */
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/* INPUTS: */
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/* unit - selects tape drive 0 (left) or 1 (right) */
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/* lbn - logical block number to be read [0..511] */
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/* buffer - address of 512 bytes containing the data to write */
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/* verify - TRUE to ask the TU58 for a verification pass */
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/* */
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/* RETURNS: operation status as reported by the TU58 */
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/* */
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PUBLIC int SDWrite (WORD unit, DWORD lbn, BYTE far *buffer, WORD count)
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{
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return disk_write (unit, buffer, lbn + partition_offset, count);
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}
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