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SVM2608 Appendix A
55
A
PPENDIX
A
A
PPENDIX
A
D
ATA
S
WAPPING
E
XAMPLE
An example is provided below detailing how data might be swapped in to get a REAL number
when the data is read “swapped”. In order to make the code easier to understand, only the portion
that shuffles the data is presented here. The VME functions that actually perform the reading of
the data are the responsibility of the user.
byte tempData[16];
int regRdata[16];
doublerealData;
union
{ char
data[8];
doublevalue;
}dblData;
// read results
data = VmeRead16(channel, Vme0x28, &Api_Result);
printf("MSB1: %02x\n", data);
regRdata[0] = data;
data = VmeRead16(channel, Vme0x2a, &Api_Result);
printf("MSB0: %02x\n", data);
regRdata[1] = data;
data = VmeRead16(channel, Vme0x2c, &Api_Result);
printf("LSB1: %02x\n", data);
regRdata[2] = data;
data = VmeRead16(channel, Vme0x2e, &Api_Result);
printf("LSB0: %02x\n", data);
regRdata[3] = data;
//
now shuffle the bytes
dblData.data[0] = (byte)((regRdata[3] & 0xff00) >> 8);
dblData.data[1] = (byte)((regRdata[3] & 0x00ff) >> 0);
dblData.data[2] = (byte)((regRdata[2] & 0xff00) >> 8);
dblData.data[3] = (byte)((regRdata[2] & 0x00ff) >> 0);
dblData.data[4] = (byte)((regRdata[1] & 0xff00) >> 8);
dblData.data[5] = (byte)((regRdata[1] & 0x00ff) >> 0);
dblData.data[6] = (byte)((regRdata[0] & 0xff00) >> 8);
dblData.data[7] = (byte)((regRdata[0] & 0x00ff) >> 0);
realData = dblData.value;
