I am developing a signal processing app using Pelles C in a Windows 64bit console. My code is processing streaming data and the main loop timing is critical. In the loop I obtain a sin and cosine floating point values to use. I have two approaches operating within the loop, one using a previously calculated lookup table and the other calculates it on the fly. Again both calculations are operating. Both calculations produce identical values. Yet when I use the values calculated on the fly the timing of the loop goes up by 80%!. Here is the code segment:
//calculated on the fly
ptrst1=ptrst+j6+25000;
t8=*ptrst1;
ptrst1=(ptrst+j6);
t9=*ptrst1;
//lookup table
t6=*ptrs++;
t7=*ptrs++;
// t6=t8;
// t7=t9;
t8 is equal to t6 and t9 is equal to t7. Yet when I take off the comment on last two lines the 80% slow down occurs. I want to look at the assembly listing to see what is happening to the compiled code but I am unable to figure out how to get it from the compiler. Whats going on?
