Memory and memory address space

In operation register, understand conceptual problems encountered. Confused memory and memory address space

 

 

 

 

 

 First, read the instructions

　r0 LDR, = 0x11000c40 

　　// 0x11000c40 GPX2CON a register address, this address space is written to the register r0 

　　LDR r1, [r0] 

　　// the address pointed to by r0 space 4-byte data, is read into memory space r1 , i.e. r1 stored data 0x11000c40 four-byte address space pointed 

　　BIC r1, # 0xF0000000 

　　// the high four clear that four bytes of data, i.e., [31:28] -> 0000 

　　ORR r1, 0x10000000 

　　// [31:28]: 0000 ---> 0001 

　　str r1, [r0] 

　　// space r1 r0 stored in the data stored in the address pointed to by 0x11000c40

 

From the above, you can know the memory address is just a number, representing a memory space, just like your house house number, you can access the memory pointed to by the address. So how big is this memory space. In the computer, the memory capacity of the basic unit is in bytes, each byte has an address, i.e., four bytes of each 32-bit memory space as a unit.