自己動手做OS, micro kernel develop on Beagleboard-XM(ARMv7) lab3 Initialize stack pointer and printk
lab3,Happy Moon Festival!!! We'll study how to initial stack and add a printk function for debug in lab3. 終於有點空閒時間了，大家中秋節快樂， 這個例子練習了ARM在開機時initial stack的部份， 並加入了一個printk的功能，以便日後debug. I just give some notes for now. start.S - __vector_reset will invoke when boot, it will initialize stack pointer then clear bss section and then invoke plat_boot function to print helloworld. 開始後會跳到__ vector_reset去進行stack initial的動作 ，然後初始化bss段，跳到 plat_boot去動作。 boots.c It will print helloworld and invoke test_printk function. 會印出helloworld並呼叫 test_printk。 source code download (原始碼下載): https://github.com/tzuCarlos/v1OS.git further study: Jserv's CuRTOS give us a nice ARM boot asm example, we'll need to disable MMU, setup stack, timer, interrupt and some hardwares. though bootloader already did some during boot, but for portal reason, a nice OS still need to initial by itself. 請先看Jserv大，寫的CuRTOS的啟動程式部份，裡面有很詳細的註解，不過今天我們只有做stack的配置。 https://github.com/jserv/CuR