Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Mon, 22 Jan 2001 12:56:34 -0700

>   
>   I'm trying to develop a driver for VMIVME 2510B,64channel digital i/o
> board.I found driver of vmivme 2534 board is somewhat similar to 2510B,so
> tailored that for 2510B.But,now I'm facing problems w.r.t. handling
> 64bit data,as the compiler doesn't support 'long long'.
>   Can anybody suggest me some way to handle this? Actually I tried with a
> structure containing two 32bit words to accomplish the goal.But,throught
> the source code of EPICS,wherever RVAL,MASK etc., are being used,I'm in
> need of changing the dependents appropriately.
>   Thanks in Advance.
> 

I would create a structure containing 32 bit unsigned integer "volatile uint32_t" 
fields that overlay your device. You could use your device specific addressing to 
locate the proper word within your structure. The situation will be similar for 
MBBI / MBBO records with the constraint that you will not be able to support bit 
field widths greater than 32 bits, nor bit fields that cross 32 bit word boundaries
in your device. The 32 bit boundary constraints is built into the design of the 
mbbi/mbbo records interface between itself and device support and could be overcome 
only by joining two mbbi records with a calculation record (or splitting a soft mbbo 
record with two calculation records). You could also write a specialized record. 

Jeff

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System