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2 pj 1 
/* Project:     OSLib
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 * Description: The OS Construction Kit
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 * Date:                1.6.2000
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 * Idea by:             Luca Abeni & Gerardo Lamastra
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 *
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 * OSLib is an SO project aimed at developing a common, easy-to-use
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 * low-level infrastructure for developing OS kernels and Embedded
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 * Applications; it partially derives from the HARTIK project but it
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 * currently is independently developed.
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 *
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 * OSLib is distributed under GPL License, and some of its code has
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 * been derived from the Linux kernel source; also some important
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 * ideas come from studying the DJGPP go32 extender.
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 *
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 * We acknowledge the Linux Community, Free Software Foundation,
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 * D.J. Delorie and all the other developers who believe in the
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 * freedom of software and ideas.
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 *
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 * For legalese, check out the included GPL license.
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 */
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/* DOS Interface toward disk            */
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#include <ll/i386/mem.h>
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#include <ll/i386/error.h>
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#include <ll/string.h>
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#include <ll/i386/x-dos.h>
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#include <ll/i386/x-dosmem.h>
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40 pj 30 
FILE(X-Dos-File);
2 pj 31 
 
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/* Basic DOS I/O Flag */
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/*#define __DEBUG__*/
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#define DOS_READ        0
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#define DOS_WRITE       1
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#define DOS_RW          2
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40 pj 40 
#define DOS_BUFSIZE     1024    /* I/O auxiliary buffer         */
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#define DOS_MAXDESCR    16      /* Maximum number of DOS file   */
2 pj 42 
 
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static DOS_FILE DOS_descr[DOS_MAXDESCR];
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/* I Hope this array is initialized with 0... */
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static BYTE busy[DOS_MAXDESCR];
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/* The Last DOS Error occurred! */
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static unsigned _DOS_error = 0;
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int DOS_init(void)
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{
40 pj 53 
  /* Init the DOS memory allocator */
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  DOS_mem_init();
2 pj 55 
 
40 pj 56 
  /* TODO: Add a check if we are run through X */
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  return 1;
2 pj 58 
}
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unsigned DOS_error(void)
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{
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    unsigned v = _DOS_error;
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    _DOS_error = 0;
40 pj 64 
    return(v);
2 pj 65 
}
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40 pj 67 
DOS_FILE *DOS_fopen(char *name,char *mode)
2 pj 68 
{
40 pj 69 
    X_REGS16 ir,or;
2 pj 70 
    X_SREGS16 sr;
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    DOS_FILE *f;
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    register int i;
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40 pj 74 
    #ifdef __DEBUG__
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        char xname[80];
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    #endif
2 pj 77 
 
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    for (i = 0; busy[i] && i < DOS_MAXDESCR; i++);
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    /* Return NULL if no descriptor is available... */
40 pj 80 
    if (i == DOS_MAXDESCR) return(NULL);
2 pj 81 
    /* Otherwise, lock the descriptor & remember the index */
40 pj 82 
    f = &DOS_descr[i]; busy[i] = 1; f->index = i;
2 pj 83 
    /* Allocate a DOS buffer for the file name */
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    f->n1 = DOS_alloc(80);
40 pj 85 
    strcpy(f->n2,name);
2 pj 86 
    if (mode[0] == 'r') {
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        /* DOS Call: Intr 0x21
40 pj 88 
                AH = 0x3D  - Open existing file
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                AL = 0,1,2 - Read,Write, R/W
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        */
2 pj 91 
        f->mode = DOS_READ;
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        ir.h.ah = 0x3D;
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        ir.h.al = f->mode;
40 pj 94 
    }
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    else if (mode[0] == 'w') {
2 pj 96 
        /* DOS Call: Intr 0x21
40 pj 97 
                AH = 0x3C  - Create a file
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                AL = File attribute [0x20 = Standard,r/w,archive]
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        */
2 pj 100 
        f->mode = DOS_WRITE;
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        ir.h.ah = 0x3C;
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        ir.x.cx = 0x20;
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    }
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    f->offset = 0;
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    /* Copy th \0 also! */
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    memcpy(f->n1, name, strlen(name) + 1);
40 pj 107 
    #ifdef __DEBUG__
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        memcpy(xname, f->n1, strlen(name) + 1);
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        message("Name is : %s -- Mode : %d\n",xname,f->mode);
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    #endif
2 pj 111 
 
112 
    /* Ask DOS to open File */
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    ir.x.dx = DOS_OFF(f->n1);
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    sr.ds = DOS_SEG(f->n1);
40 pj 115 
    X_callBIOS(0x21,&ir,&or,&sr);
2 pj 116 
    f->handle = (!(or.x.cflag) ? or.x.ax : -1);
117 
 
118 
    if (f->handle == -1) {
119 
        /* DOS request failed! Release the used resources */
40 pj 120 
        DOS_free(f->n1,80);
2 pj 121 
        busy[i] = 0;
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        _DOS_error = or.x.ax;
40 pj 123 
        return(NULL);
2 pj 124 
    }
40 pj 125 
 
2 pj 126 
    /* Allocate the DOS buffer for temporary I/O */
127 
    f->buf = DOS_alloc(DOS_BUFSIZE);
40 pj 128 
    return(f);
2 pj 129 
}
130 
 
40 pj 131 
void DOS_fclose(DOS_FILE *f)
2 pj 132 
{
40 pj 133 
    X_REGS16 ir,or;
2 pj 134 
    X_SREGS16 sr;
135 
 
40 pj 136 
    if (f == NULL || busy[f->index] == 0) return;
2 pj 137 
    /* DOS Call: Intr 0x21
40 pj 138 
            AH = 0x3E  - Close a file
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            BX = File handle
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    */
2 pj 141 
    ir.h.ah = 0x3E;
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    ir.x.bx = f->handle;
40 pj 143 
    X_callBIOS(0x21,&ir,&or,&sr);
144 
    DOS_free(f->buf,DOS_BUFSIZE);
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    DOS_free(f->n1,80);
2 pj 146 
    busy[f->index] = 0;
147 
}
148 
 
40 pj 149 
DWORD DOS_fread(void *abuf,DWORD size,DWORD num,DOS_FILE *f)
2 pj 150 
{
40 pj 151 
    X_REGS16 ir,or;
2 pj 152 
    X_SREGS16 sr;
40 pj 153 
    DWORD count = size*num,now = 0,chunk;
2 pj 154 
    BYTE done = 0;
40 pj 155 
    BYTE *buf = (BYTE *)(abuf);
156 
 
2 pj 157 
    while (done == 0) {
158 
        /* Fragment the read operation ... */
40 pj 159 
        if (count > DOS_BUFSIZE) chunk = DOS_BUFSIZE;
160 
        else chunk = count;
2 pj 161 
        /* DOS Call: Intr 0x21
40 pj 162 
                AH = 0x3F  - Read data using a file handle
163 
                BX = File handle
164 
                CX = Buffer size
165 
                DS:DX = Segment:Offset of the Buffer
166 
        */
2 pj 167 
        ir.h.ah = 0x3F;
168 
        ir.x.bx = f->handle;
169 
        ir.x.cx = chunk;
170 
        ir.x.dx = DOS_OFF(f->buf);
171 
        sr.ds = DOS_SEG(f->buf);
40 pj 172 
        X_callBIOS(0x21,&ir,&or,&sr);
2 pj 173 
        /* If it was OK ... */
174 
        if (!(or.x.cflag)) {
175 
            /* Copy data into application buffer */
176 
            memcpy(buf, f->buf, or.x.ax);
177 
            buf += or.x.ax;
178 
            now += or.x.ax;
179 
            f->offset += or.x.ax;
180 
            count -= or.x.ax;
181 
            /*
40 pj 182 
                Finish if we have read all the data or
183 
                if we have read less data than how expected
184 
            */ 
185 
            if (now == size*num || or.x.ax != chunk) done = 1;     
2 pj 186 
        } else {
187 
            done = -1;
188 
            _DOS_error = or.x.ax;
189 
        }
190 
    }
40 pj 191 
    return(now);
2 pj 192 
}
193 
 
40 pj 194 
DWORD DOS_fwrite(void *abuf,DWORD size,DWORD num,DOS_FILE *f)
2 pj 195 
{
40 pj 196 
    X_REGS16 ir,or;
2 pj 197 
    X_SREGS16 sr;
40 pj 198 
    DWORD count = size*num,now = 0,chunk;
2 pj 199 
    BYTE done = 0;
40 pj 200 
    BYTE *buf = (BYTE *)(abuf);
201 
 
2 pj 202 
    while (done == 0) {
203 
        /* Fragment the write operation ... */
40 pj 204 
        if (count > DOS_BUFSIZE) chunk = DOS_BUFSIZE;
205 
        else chunk = count;
2 pj 206 
        /* Copy data from application buffer */
207 
        memcpy(f->buf, buf, chunk);
208 
        /* DOS Call: Intr 0x21
40 pj 209 
                AH = 0x40 - Write data using a file handle
210 
                BX = File handle
211 
                CX = Buffer size
212 
                DS:DX = Segment:Offset of the Buffer
213 
        */
2 pj 214 
        ir.h.ah = 0x40;
215 
        ir.x.bx = f->handle;
216 
        ir.x.cx = chunk;
217 
        ir.x.dx = DOS_OFF(f->buf);
218 
        sr.ds = DOS_SEG(f->buf);
40 pj 219 
        X_callBIOS(0x21,&ir,&or,&sr);
2 pj 220 
        /* If it was OK ... */
221 
        if (!(or.x.cflag)) {
222 
            f->offset += or.x.ax;
223 
            count -= or.x.ax;
224 
            buf += or.x.ax;
225 
            now += or.x.ax;
40 pj 226 
            if (now == size*num || or.x.ax != chunk) done = 1;     
2 pj 227 
        } else {
228 
            done = -1;
229 
            _DOS_error = or.x.ax;
230 
        }
231 
    }
40 pj 232 
    return(now);
2 pj 233 
}
40 pj 234