Embedded Systems: An Integrated Approach by Pearson

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10.19 | Readonly and Read/Write Memory

 e two memory areas defi ned by the compiler are ‘Readonly’ for code, and ‘Read/write’

for data. Usually this corresponds to ROM and RAM in a physical system. RAM is used

for intermediate results, for temporary storage, etc., as this is volatile memory. We can

store data permanently in the readonly memory, process it and copy it in RAM. In the

readonly memory, data is written using directives like DCD, DCW, etc. From there, it is

copied to readwrite memory using load and store instructions.

Example 10.15

AREA FIRST, CODE, READONLY

ENTRY

LDR R7, ...