Sat Feb 7 13:05:06 EST 2015
PIC vs ARM
Diving into Cortex M3 assembly and finding out that a lot of
instruction cycles are needed to just set a bit in a device register.
Here, clearing the timer interrupt bit (TIM2.SR.UIF bit on STM32F103).
Comment is cycle count.
ldr r3, tim2_sr @; 2
ldr r2, [r3, #0] @; 2
bic r2, r2, #1 @; 1
str r2, [r3, #0] @; 2
Re-appreciating PIC18's single cycle bit set/clear instructions.
EDIT: Maybe this can be fixed with bit banding?