ARMask.The ARM has six OPERATING modes:
• User (unprivileged mode under which most tasks run)
• FIQ (entered when a high priority (fast) interrupt is raised)
• IRQ (entered when a low priority (normal) interrupt is raised)
• Supervisor (entered on reset and when a Software Interrupt instruction is
executed)
• Abort (used to handle memory access violations)
• Undef (used to handle undefined instructions)
* ARM Architecture Version 4 adds a seventh mode:
• System (privileged mode using the same registers as user mode)
I use C to implement thread OPERATING,include initiallize,fork,yield,exit,kill. You should have driver to use this library. I choose array for ready queue,and strcut for Thread Control Block.
Simple OPERATING Systems （簡稱SOS）是一個可以運行在X86平臺上（包括QEMU，BOCHS，VirtualBOX等模擬器上）的面向教學的微型嵌入式操作系統(tǒng)系列軟件。從SOS-1到SOS9，逐步完成了一個從無（只有顯示）到有（虛存、文件系統(tǒng)、線程、進程）的操作系統(tǒng)創(chuàng)建過程。通過分析、運行和修改此操作系統(tǒng)，會對操作系統(tǒng)的實際實現(xiàn)有更深入的的了解。這是第一部分 SOS-1。
