[avr-gcc-list] VMA & LMA address -- confused ?

[Dinesh Guleria]

Hi,

 

I am bit confused about VMA & LMA address for AVR.

Virtual memory address & Load Memory Address.

1> What actually does it means ???????

 

What i got from reading is that VMA is passed to linker & .ELF is created.

While avr-objcopy read .elf & creats the .hex  in this hex file .crt code will place the data variable to LMA.

& .eep file in this file epprom variables are placed to LMA.

 

 

Because of harvard architectue to avoid confusion related to memory address ( because EEPROM, RAM & Flash all will start from 0x0000 i.e ZERO address) GCC does following :---

Add 0x800000 the to real SRAM   --- if you want the .data section to start at 0x1100, pass 0x801100 at the address
Add 0x810000 the to real EEPROM

2> What does it add for the ROM address, i am bit confused --- ????????

3> Also why this typical number series are chosen 0x800000 .... ???????

 

This operation produces VMA. This is only my understanding & assumption.

 

 

Please correct me for the above three question.

 

BR