/* header information for low speed hpib disk driver */

/*   command macros   */

#define  lh_auxcommand  lh_wrtptr->t_aux_cmd 
#define  lh_intmask0    lh_wrtptr->t_i_msk0
#define  lh_intmask1    lh_wrtptr->t_i_msk1
#define  lh_serialpoll  lh_wrtptr->t_serial_poll_resp
#define  lh_parapoll    lh_wrtptr->t_parallel_poll_resp
#define  lh_commandpass lh_readptr->t_cmd_pass_thru
#define  lh_dataout     lh_wrtptr->t_data_out
#define  lh_instat0     lh_readptr->t_i_st0
#define  lh_instat1     lh_readptr->t_i_st1
#define  lh_ienab       lh_wrtptr->t_int_dma_stat
#define  lh_busstat     lh_readptr->t_bus_stat
#define  lh_datain      lh_readptr->t_data_in
#define  lh_addrstat	lh_readptr->t_bus_ctl_addr_stat


/* parameters for the HPIB commands macros and aids */

#define LH_END	      0x08	       /* end of data indicator in instat0 */
#define BYTEOUT       0x10             /* interface ready to accept next data */
#define BYTEIN        0x20	       /* data byte accepted */
#define BYTE_TIMEOUT  100000           /* time to wait for a byte to come in
				       /* or go out on the hpib bus           */
       

/* place to put garbage when clearing datain */
char trash;


/* defines for detecting the attention state */

#define lh_atn          0x80
#define lh_atn_on          (lh_busstat & lh_atn)


/* HPIB command macros and aids */

#define lh_data              if (lh_atn_on) {lh_auxcommand = cmdrhdf; lh_auxcommand = cmdgts; }  /* turn off ATN */
#define lh_cmd               if (!(lh_atn_on)) {lh_auxcommand = cmdtca; lh_waitout( LH_DIE );} /* ATN on */  
#define lh_eoi               lh_auxcommand = cmdfeoi /* set eoi with next data byte */
       
#define lh_ltnself           lh_auxcommand = cmdlon1 /* set self as listener */
#define lh_tlkself           lh_auxcommand = cmdton1 /* set self as talker */
#define lh_unltnself         lh_auxcommand = cmdlon0 /* unlisten self */
#define lh_untlkself         lh_auxcommand = cmdton0 /* untalk self */

#define lh_unlisten          lh_cmd; lh_out( H_UNL ); lh_unltnself;  /* unlisten all */
#define lh_untalk            lh_cmd; lh_out( H_UNT ); lh_untlkself;   /* untalk all   */
#define lh_shutup            lh_untalk; lh_out( H_UNL ); lh_unltnself;

#define lh_ltnadr( lh_unit )    lh_unit | H_DLAC /* put together full listen HPIB addr */
#define lh_tlkadr( lh_unit )    lh_unit | H_DTAC /* put together full talker HPIB addr */

/* set up for sending bytes over HPIB */
#define lh_inbound( lh_unit )   lh_cmd; lh_out( H_PLA ); lh_ltnself; lh_out( lh_tlkadr( lh_unit ) ); lh_wait()

/* set up for receiving bytes over HPIB */
#define lh_otbound( lh_unit )   lh_cmd; lh_out( H_PTA ); lh_tlkself; lh_out( lh_ltnadr( lh_unit ) ); lh_wait() 

/* macro to send data over the bus (panic if there is a timelh_out) */
#define lh_out( lh_item )          lh_dataout=lh_item; lh_waitout( LH_DIE )


#define lh_cleardata trash = lh_datain  /* clear out datain register */