Posted on April 23, 2014 at 14:08Hi
I am doing a simple thing in C basically witing it to the PORT I register
short int a[1] = {1,0};
short int *p = &a;
while(1)
{
GPIOI->ODR |= *p;
}
Basically fetching data from memory and writing it to the PORT I . I have to write a very long array but for easier understanding, I have used small array. I thought it should take a less clock cycle like 4 max 5 but it is taking so much how can i reduce the clock cycles ...for just writing also it is taking so much clock cycles . what should i do to lessen it
The disassembly for his instruction is
74 GPIOI->ODR |= *p;
0800042c: mov.w r3, #8192 ; 0x2000
08000430: movt r3, #16386 ; 0x4002
08000434: mov.w r2, #8192 ; 0x2000
08000438: movt r2, #16386 ; 0x4002
0800043c: ldr r1, [r2, #20]
0800043e: movw r2, #56 ; 0x38
08000442: movt r2, #8192 ; 0x2000
08000446: ldr r2, [r2, #0]
08000448: ldrh r2, [r2, #0]
0800044a: sxth r2, r2
0800044c: orrs r2, r1
0800044e: str r2, [r3, #20]
82 }
