8-bit MicrocontrollersのトピックRe: 32 bits Math Operations HCS08

32 bits Math Operations HCS08

adrianodangelo — Tue, 13 Oct 2015 19:56:45 GMT

Hello All,

I am new on Codewarrior and in my current project(9S08PA8) I need a 32 bits variable to receive the result of a math operation.

This variable will receive a value from a single multiply operation(eg. ADC_result x 87).

Below a snippet of my code:

uint8_t Mult=87;

uint32_t temp=0;

temp=(uint32_t)(adc_result0*Mult);

What happens is that if the value of adc_result0 is below or equal to 753 (the result ocupy only 2 bytes) everything is ok, but if the adc_result0 is higher than 753 (the result does not fill in 2 bytes) the compiler casts the result to 2 bytes. My question is can the HCS08 compiler operate in 32 bits variables? If not, what workaround can I use to solve this problem? (I tried to declare the variable as dword, unsigned long, long, without success).

Thanks,

Re: 32 bits Math Operations HCS08

kef2 — Wed, 14 Oct 2015 04:01:16 GMT

This is how C works. 16 bits operation gives 16 bits result. You need to implicitly cast at least one of multipliers to 32 bits to get 32 bits product.

temp=(uint32_t)( (uint32_t)adc_result0*Mult);

Regards,

Edward

Re: 32 bits Math Operations HCS08

adrianodangelo — Wed, 14 Oct 2015 10:49:44 GMT

Thank you Eduards,

Perfect! You solved my problem and saved me a lot of time.