About PGogo

PGogo · 2018-11-19

Hello. I am using STM32F4279ZI MCU with FreeRTOS. I want to compare efficiency of bare-metal and OS based program implementation. While doing some tests I have noticed that the same function called from bare-metal aplication is much slower than that ...

PGogo · 2018-11-22

@Community member Thank you for your help. The problem is in global stack localization. When i changed stack's address from 0x20030000 to 0x20010000 (from SRAM3 to SRAM1) executon times are equal. In STM32F427xx STM32F429xx Datasheet in 'Multi-AHB ...

PGogo · 2018-11-21

Ok. I will try to locate global stack in the same memory area as FreeRTOS locates its own. If results will be equal in both implementations, your are right. If not, I will try to contact with ST or ARM. Is that link correct? I don't see any connect...

PGogo · 2018-11-21

Is any documentation about it? When I take a look at addreses in 'normal' function they are like:2002ffd82002ffdc2002ffd4and variables' adresses when foo() is called from task:20000370200003742000036cso you might be right. Is any possibility to alloc...

PGogo · 2018-11-20

Ok. Thank you for an explanation. However, why that foo function in my first post takes 220524 cpu cycles when calling from main while in task it takes 200704 cpu cycles?On the other way when i measure time of 'i++" operation it executes 10 cpu cycle...

PGogo · 2018-11-20

It isn't in this example. To check this I used: DWT->CYCCNT = 0; asm("ldr r3, [r3, #4]"); printf("ldr %d\r\n", DWT->CYCCNT); DWT->CYCCNT = 0; asm("str r3, [r7, #0]"); printf("str %d\r\n", DWT->CYCCNT);At the begining of foo...

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LDR and STR asm instruction different execution time?

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Re: LDR and STR asm instruction different execution time?

Re: LDR and STR asm instruction different execution time?

Re: LDR and STR asm instruction different execution time?