ZI Data extends area assigned in linker script

You wrote:
> Fall back how exactly?

This is the linker File:

LR_IROM1 0x08000000 0x00200000  {    ; load region size_region
  ER_IROM1 0x08000000 0x00200000  {  ; load address = execution address
   *.o (RESET, +First)
   *(InRoot$$Sections)
   .ANY (+RO)
  }
  RW_IRAM1a 0x20000000 0x00025000  {  ; RW data
   .ANY (+RW +ZI)
  }
  RW_IRAM1b 0x20025000 0x00025000  {
     *.o(STACK, +Last)
  }

; [20160314_HeapInSdRam_NewCode]
   RW_SDRAM 0xD0000000 0x00780000 { ; 8 MB
   *.o (HEAP, +First)
  }
; [/20160314_HeapInSdRam_NewCode]

}

This is the MAP file:

    Total RO  Size (Code + RO Data)              1526544 (1490.77kB)
    Total RW  Size (RW Data + ZI Data)           8038188 (7849.79kB)
    Total ROM Size (Code + RO Data + RW Data)    1534664 (1498.70kB)

As you see the RW/ZI Data is assigned to area RW_IRAM1a with size 0x25000.
The map file states that RW+ZI Data is BIGGER than this size.
My question was: How can this work?

Now you said

>> You're directing the heap initialization into the SDRAM so the the bulk of the ZI is likely there

That's why i assumed:

a) Does RW_IRAM1a area automatically fallback to use the HEAP ? => yes

Actually, as the RW_IRAM1a is not big enough to hold all the ZI Data it shouldn't work. But it does. That's what i dont understand. It can only work if the linker automatically ignores the ZI assignment done in the linker file and puts it to sdram on its own. (?)

You wrote:
> Fall back how exactly?

This is the linker File:

LR_IROM1 0x08000000 0x00200000  {    ; load region size_region
  ER_IROM1 0x08000000 0x00200000  {  ; load address = execution address
   *.o (RESET, +First)
   *(InRoot$$Sections)
   .ANY (+RO)
  }
  RW_IRAM1a 0x20000000 0x00025000  {  ; RW data
   .ANY (+RW +ZI)
  }
  RW_IRAM1b 0x20025000 0x00025000  {
     *.o(STACK, +Last)
  }

; [20160314_HeapInSdRam_NewCode]
   RW_SDRAM 0xD0000000 0x00780000 { ; 8 MB
   *.o (HEAP, +First)
  }
; [/20160314_HeapInSdRam_NewCode]

}

This is the MAP file:

    Total RO  Size (Code + RO Data)              1526544 (1490.77kB)
    Total RW  Size (RW Data + ZI Data)           8038188 (7849.79kB)
    Total ROM Size (Code + RO Data + RW Data)    1534664 (1498.70kB)

As you see the RW/ZI Data is assigned to area RW_IRAM1a with size 0x25000.
The map file states that RW+ZI Data is BIGGER than this size.
My question was: How can this work?

Now you said

>> You're directing the heap initialization into the SDRAM so the the bulk of the ZI is likely there

That's why i assumed:

a) Does RW_IRAM1a area automatically fallback to use the HEAP ? => yes

Actually, as the RW_IRAM1a is not big enough to hold all the ZI Data it shouldn't work. But it does. That's what i dont understand. It can only work if the linker automatically ignores the ZI assignment done in the linker file and puts it to sdram on its own. (?)

Ok i learned about the difference between compressed size of the rw data and zi data in the flash and the uncompressed size in the ram.

For a trial I set size of RW_IRAM1a to 0 in the linker script and the linker says:

.\Bin\RehmMNr1\RehmMNr1Simu.axf: Error: L6407E: Sections of aggregate size 0x577c bytes could not fit into .ANY selector(s).

So this shows the RW/ZI size in the ram is 0x577c bytes (the size it fails to reserve).

It seems there is not automatic fallback to other region.

Still i wonder what this final size of 8038252 Bytes at the end of the map file is.