Racal 3161 Waveform Generator

[John Faucett <faucett@lanl.gov>]

I'm writing device support for a Racal 3161 VXI Waveform Generator 
with a Baja68K IOC.  Has anyone else done this? Everything works 
except for the shared memory download.  Here's the commands:

OUTP OFF;:TRAC DEF 1,32,1;:TRAC SEL 1
SMEM:MODE WRITE;:SMEM:STAT ON
*OPC?
(wait for response to be 1)
(copy array of short integers to A24 memory)
SMEM:STAT OFF;:FUNC:MODE USER;:OUTP ON;:OUTP:SYNC ON

The copy routine is (in simplified form)

#include <drvEpvxi.h>
LOCAL STATUS copy_n_points( int la, short *points, int n) {
    short *pbase;
    struct vxi_csr *pcsr;
    char  *VMEaddr = NULL;

    pcsr = VXIBASE( la);
    VMEaddr = ( char *) ( pcsr->dir.w.offset<<8);
    sysBusToLocalAdrs( VME_AM_STD_SUP_DATA, VMEaddr, ( char **) &pbase);
    memcpy(( void *) pbase, ( void *) points, 2*n);
}

If I copy a large number of points, say 1000, the waveform changes, 
although it isn't what I expect.  Copying a small number of points 
has no effect.  Perhaps this indicates that pbase is being calculated 
incorrectly.