- Ask a related questionWhat is a related question?A related question is a question created from another question. When the related question is created, it will be automatically linked to the original question.
Hello,
Please see below. Shouldn't cc and dd have the same result? I have also tried casting to a signed long and compiler versions ,v6.4.1 and v6.2.10.
Stephen
C Code:
unsigned int xx = 65494; //=0xFFD6
signed int yy = -42; // = 0xFFD6
int main(void)
{
unsigned long int cc = 0;
unsigned long int dd = 0;
cc = ((long)xx)*((long)xx); //cc = 4289464036
dd = ((long)yy)*((long)yy); //dd = 1764
return 0;
}Assembly Code:
main(): 0000cb: FE04 ADDB SP, #4 12 unsigned long int cc = 0; 0000cc: 0200 MOVB ACC, #0 0000cd: 1E42 MOVL *-SP[2], ACC 13 unsigned long int dd = 0; 0000ce: 1E44 MOVL *-SP[4], ACC 15 cc += ((long)xx)*((long)xx); 0000cf: 761F000C MOVW DP, #0xc 0000d1: 2D08 MOV T, @0x8 0000d2: 3608 MPYU ACC, T, @0x8 0000d3: 0742 ADDL ACC, *-SP[2] 0000d4: 1E42 MOVL *-SP[2], ACC 16 dd += ((long)yy)*((long)yy); 0000d5: 2D09 MOV T, @0x9 0000d6: 1209 MPY ACC, T, @0x9 0000d7: 0744 ADDL ACC, *-SP[4] 0000d8: 1E44 MOVL *-SP[4], ACC 18 return 0; 0000d9: 9A00 MOVB AL, #0x0 19 } 0000da: FE84 SUBB SP, #4 0000db: 0006 LRETR
