summary : kernel 관련 기억/요약/link
Kernel(1)
참고 : http://studyfoss.egloos.com/category/Kernel
typeof
GCC permits the identification of a type through the reference to a variable. This kind of operation permits a form of what’s commonly referred to as generic programming. Similar functionality can be found in many modern programming languages such as C++, Ada, and the Java™ language. Linux uses typeof to build type-dependent operations such as min and max. Listing 1 shows how you can use typeof to build a generic macro (from ./linux/include/linux/kernel.h). Listing 1. Using typeof to build a generic macro
#define min(x, y) ({ \
typeof(x) _min1 = (x); \
typeof(y) _min2 = (y); \
(void) (&_min1 == &_min2); \
_min1 < _min2 ? _min1 : _min2; })
Clock Domain
| Clock Domain | Description | | ———— | ———— | | DCLK | Debugger clock synchronous to core | | FCLK | WIC clock | | SCLK | System Tick and NVIC clock | | HCLK | AHB peripheral clock without keep awake feature | | GCLK | AHB peripheral clock with keep awake feature | | PCLK | APB peripheral clock with keep awake feature | | CLK | Primary clock input to hardened subsystem | | PLLCLK | Primary clock input to digital section of the via configurable ASIC |
- FCLK : cpu에서 사용되는 클럭
- HCLK : AHB 버스에 사용되는 클럭(메모리 컨트롤러, 인터럽트 컨트롤러, LCD 컨트롤러, DMA, USB 호스트 등에서 사용)
- PCLK : APB 버스에 사용되는 클럭(WDT, 타이머, ADC, UART, GPIO, RTC, SPI 등에서 사용)
initrd, ramdisk
참고 link : http://egloos.zum.com/furmuwon/v/11145268
