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ccs int32 calculation

 
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lgeorge123



Joined: 05 Dec 2004
Posts: 31

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ccs int32 calculation
PostPosted: Wed Mar 18, 2009 7:30 am     Reply with quote
I have a prgram to calculate some variables.
Code:
int16 cal_x_min,cal_x_max,cal_y_min,cal_y_max,x_coord,y_coord;
int32 x_coord320,y_coord240
cal_x_min=0x0123;
cal_x_max=0x0034;
cal_y_min=0x0567;
cal_y_max=0x0456;
x_coord=cal_x_min-0x0007;
y_coord=cal_y_min-0x0001;
x_coord320 = (x_coord * 320) / (cal_x_min - cal_x_max);
 y_coord240 = ((y_coord *240) - 240) / (cal_y_min - cal_y_max);

using the above calculation the result is wrong (x_coord320 and y_coord240) , can somebody give me some suggestions ????
Wayne_



Joined: 10 Oct 2007
Posts: 681

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PostPosted: Wed Mar 18, 2009 8:07 am     Reply with quote
Need to cast your 16 bit vars to 32 bits to force the compiler to use 32 bit maths in the equation

Code:

x_coord320 = ((int32)x_coord * 320) / (cal_x_min - cal_x_max);
y_coord240 = (((int32)y_coord *240) - 240) / (cal_y_min - cal_y_max);
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