Cx51 Compliler, 8051 Memory type

참고 사이트 : https://www.keil.com/support/man/docs/c51/c51_le_memtypes.htm

 

Memory TypeDescription

code	Program memory (64 KBytes); accessed by opcode MOVC @A+DPTR.
data	Directly addressable internal data memory; fastest access to variables (128 bytes).
idata	Indirectly addressable internal data memory; accessed across the full internal address space (256 bytes).
bdata	Bit-addressable internal data memory; supports mixed bit and byte access (16 bytes).
xdata	External data memory (64 KBytes); accessed by opcode MOVX @DPTR.
far	Extended RAM and ROM memory spaces (up to 16MB); accessed by user defined routines or specific chip extensions (Philips 80C51MX, Dallas 390).
pdata	Paged (256 bytes) external data memory; accessed by opcode MOVX @Rn.

아래, 사용의 예

char data var1;
char code text[] = "ENTER PARAMETER:";
unsigned long xdata array[100];
float idata x,y,z;
unsigned int pdata dimension;
unsigned char xdata vector[10][4][4];
char bdata flags;