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CPM OPERATING SYSTEMS/CPM 68K/1.0X SOURCES/v101/boot/iosys.c

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+
+/****************************************************************
+*								*
+*		CP/M-68K BDOS Disk I/O System Module		*
+*								*
+*	This module translates from the packet oriented I/O	*
+*	passed from the other BDOS modules into BIOS calls.	*
+*								*
+*	It includes only one external entry point:
+*		do_phio()   - do physical i/o			*
+*								*
+*								*
+*	Configured for Alcyon C on the VAX			*
+*								*
+****************************************************************/
+
+#include "stdio.h"		/* Standard I/O declarations */
+
+#include "bdosdef.h"		/* Type and structure declarations for BDOS */
+
+#include "pktio.h"		/* Packet I/O definitions */
+
+#include "biosdef.h"		/* Declarations for BIOS entry points */
+
+EXTERN	udiv();			/* Assembly language unsigned divide routine */
+				/* in bdosif.s.  It's used because Alcyon C  */
+				/* can't do / or % without an external */
+
+/************************
+*  do_phio entry point	*
+************************/
+
+UWORD do_phio(iop)
+
+REG struct iopb *iop;		/* iop is a pointer to a i/o parameter block */
+
+{
+    REG struct dph *hdrp;	  /* pointer to disk parameter header	*/
+    REG struct dpb *dparmp;	  /* pointer to disk parameter block	*/
+    struct
+    {				/* structure for results of external divide */
+	UWORD iotrk;
+	UWORD iosect;
+    } iopdiv;
+
+    LOCK		/* lock the disk system while doing physical i/o */
+
+    switch (iop->iofcn)
+    {
+	case sel_info:	
+		iop->infop = bseldsk(iop->devnum, iop->ioflags);
+		break;
+
+	case read:
+		hdrp = iop->infop;
+		dparmp = hdrp->dpbp;
+		udiv( iop->devadr, dparmp->spt, &iopdiv );
+		bsettrk( iopdiv.iotrk + dparmp->trk_off );
+		bsetsec( bsectrn( iopdiv.iosect, hdrp->xlt ) );
+		bsetdma(iop->xferadr);
+		return(bread());
+
+    }
+
+    UNLOCK
+    return(0);
+}