Explanation for the basics of datatypes

Code:

Multilication function1
int32_t z; 
z=mutliplication ( 0x1234, 0x5678); 
return z >> 15;

Z shifted right 15 times...
i don't know why result of muttiplication is divided by 2^15 (/ 32768)
if you want to get the sign
return z>>31 most significatif bit is the sign 1=Negativ 0 Positive

Code:

Multilication function2
signed long z; 
RESLO and RESHI =mutliplication ( 0x1234, 0x5678); //if results are stored in two different variables of 16bits(RESLO=lower,RESHI=higher)
z = RESHI; 
z = (result<<16)|RESLO;

Bad results !

from where do you find "result" variable ?

Code:

z =mutliplication ( 0x1234, 0x5678)
RESHI=(int16) ( z>>16);
RESLO=( int16 ) (z & 0x0000FFFF);

Click to expand...