65 lines
1.6 KiB
C
65 lines
1.6 KiB
C
/*
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* DOS interrupt 25h handler
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "msdos.h"
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#include "ldt.h"
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#include "miscemu.h"
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#include "drive.h"
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#include "debug.h"
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/**********************************************************************
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* INT_Int25Handler
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*
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* Handler for int 25h (absolute disk read).
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*/
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void WINAPI INT_Int25Handler( CONTEXT *context )
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{
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BYTE *dataptr = CTX_SEG_OFF_TO_LIN( context, DS_reg(context), EBX_reg(context) );
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DWORD begin, length;
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int fd;
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if (!DRIVE_IsValid(AL_reg(context)))
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{
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SET_CFLAG(context);
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AX_reg(context) = 0x0101; /* unknown unit */
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return;
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}
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if (CX_reg(context) == 0xffff)
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{
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begin = *(DWORD *)dataptr;
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length = *(WORD *)(dataptr + 4);
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dataptr = (BYTE *)CTX_SEG_OFF_TO_LIN( context,
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*(WORD *)(dataptr + 8), *(DWORD *)(dataptr + 6) );
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}
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else
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{
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begin = DX_reg(context);
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length = CX_reg(context);
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}
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TRACE(int, "int25: abs diskread, drive %d, sector %ld, "
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"count %ld, buffer %d\n",
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AL_reg(context), begin, length, (int) dataptr);
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if ((fd = DRIVE_OpenDevice( AL_reg(context), O_RDONLY )) != -1)
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{
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lseek( fd, begin * 512, SEEK_SET );
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/* FIXME: check errors */
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read( fd, dataptr, length * 512 );
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close( fd );
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}
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else
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{
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memset(dataptr, 0, length * 512);
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if (begin == 0 && length > 1) *(dataptr + 512) = 0xf8;
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if (begin == 1) *dataptr = 0xf8;
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}
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RESET_CFLAG(context);
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}
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