This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Arm7 long multiply in C

Hallo to everyone.

My problem is to have the upper 4 Byte result of a multiply.
For example:

unsigned int a=1000000000;//only example value
unsigned int b=10000000000;
unsigned int c;



the result of a*b = 0x8AC7230489E80000

How to get the upper 4 Bytes:
0x8AC72304
How to get the lower 4 Bytes:
0x89E80000

Can anybody help?
I have to programm a super-fast-interrupt-routine for an microcontroller, there is not enough time for floating point.

0