Erfarenheter av Raspberry Pi

Tillbaka till Raspberry Pi.
Inledning.
Blinking LED.
Referenser.

Inledning.

Den här sidan ska försöka beskriva användning av assembler för Raspberry Pi. Jag började med att skapa en undermap till /home/pi, /home/pi/Development/Assembler.
Även programpaketet wiringPi måste vara installerat.

Blinking LED.

@ blink.s @ D. Thiebaut @ based on the following C program: @ @ #include <wiringPi.h> @ #include <stdio.h> @ #include <stdlib.h> @ @ int main (void) { @ int pin = 7; @ printf("Raspberry Pi wiringPi blink test\n"); @ @ if (wiringPiSetup() == -1) { @ printf( "Setup didn't work... Aborting." ); @ exit (1); @ } @ @ pinMode(pin, OUTPUT); @ int i; @ for ( i=0; i<10; i++ ) { @ digitalWrite(pin, 1); @ delay(250); @ @ digitalWrite(pin, 0); @ delay(250); @ } @ @ return 0; @ } @ @ To assemble, link, and run: @ @ as -o blink.o blink.s @ gcc -o blink2 blink.o -lwiringPi @ sudo ./blink2 @ --------------------------------------- @ Data Section @ --------------------------------------- .data .balign 4 Intro: .asciz "Raspberry Pi wiringPi blink test\n" ErrMsg: .asciz "Setup didn't work... Aborting...\n" pin: .int 7 i: .int 0 delayMs: .int 250 OUTPUT = 1 @ --------------------------------------- @ Code Section @ --------------------------------------- .text .global main .extern printf .extern wiringPiSetup .extern delay .extern digitalWrite .extern pinMode main: push {ip, lr} @ push return address + dummy register @ for alignment @ printf( "blink..." ) ; ldr r0, =Intro bl printf @ if (wiringPiSetup() == -1) { @ printf( "Setup didn't work... Aborting." ) ; @ exit (1) ; @ } bl wiringPiSetup mov r1,#-1 cmp r0, r1 bne init ldr r0, =ErrMsg bl printf b done @ pinMode(pin, OUTPUT) ; init: ldr r0, =pin ldr r0, [r0] mov r1, #OUTPUT bl pinMode @ for ( i=0; i<10; i++ ) { ldr r4, =i ldr r4, [r4] mov r5, #10 forLoop: cmp r4, r5 bgt done @ digitalWrite(pin, 1) ; ldr r0, =pin ldr r0, [r0] mov r1, #1 bl digitalWrite @ delay(250) ; ldr r0, =delayMs ldr r0, [r0] bl delay @ digitalWrite(pin, 0) ; ldr r0, =pin ldr r0, [r0] mov r1, #0 bl digitalWrite @ delay(250) ; ldr r0, =delayMs ldr r0, [r0] bl delay add r4, #1 b forLoop done: pop {ip, pc} @ pop return address into pc

Kompilera programet:
as -o blink.o blink.s gcc -o blink2 blink.o -lwiringPi sudo ./blink2

Referenser.

Tutorial: Assembly Language with the Raspberry Pi.
ARM Architecture for the Digital World
ARM Assembler.

Till början.