gcc linker to combine memory blocks into one sector

Question

Is there a way for the gnu linker to combine memory blocks so the linker will use one sector name when assigning memory?

For example:

MEMORY
{
  RAM1 (xrw)               : ORIGIN = 0x20000480, LENGTH = 0x0BB80  
  RAM2 (xrw)              : ORIGIN = 0x2001C000, LENGTH = 0x03C00
}

Can there be a memory block our sector that includes memory blocks RAM1 and RAM2? Something like this below:

.bss : 
{
    _bss_start = .;
    *(.bss)
    *(.bss.*)
    *(COMMON)
    _bss_end = .;
} >RAM >RAM1

Answer 1

Good question. There are multiple ways of to do this. One way would be to actually split the BSS section by selecting which file's BSS goes where.

MEMORY
{
  RAM1 (xrw)               : ORIGIN = 0x20000480, LENGTH = 0x0BB80  
  RAM2 (xrw)              : ORIGIN = 0x2001C000, LENGTH = 0x03C00
}


SECTIONS
   {
           .bss1:
           {
                   f1.o
                   . =+ 0x200;
                   f2.o (.bss)
           } >RAM1
           .bss2:
           {
                   f3.o (.bss)
                   f4.o (.bss) = 0x1234
           } >RAM2
   }

Instead of doing this for each file (only useful if you have tiny RAM/ROM chips), I recommend to just place for example COMMON on RAM2, and .bss on RAM1.