From 36a464f80223cf1ca96c859dcc265550bf8f7b39 Mon Sep 17 00:00:00 2001
From: Alwin Berger <alwin.berger@tu-dortmund.de>
Date: Thu, 26 Jan 2023 14:01:02 +0100
Subject: [PATCH] link data in flash to save on copy

---
 .../Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c |  8 ++++----
 .../CORTEX_M3_MPS2_QEMU_GCC/scripts/mps2_m3.ld  | 17 ++++++++---------
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
index 41a561fd..0c8ea57a 100644
--- a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
+++ b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/init/startup.c
@@ -52,10 +52,10 @@ void Reset_Handler( void )
     __asm volatile ( "mov sp, r0" );
 
     /* copy .data section from flash to RAM */
-    for( uint32_t * src = &_sidata, * dest = &_sdata; dest < &_edata; )
-    {
-        *dest++ = *src++;
-    }
+    // for( uint32_t * src = &_sidata, * dest = &_sdata; dest < &_edata; )
+    // {
+    //     *dest++ = *src++;
+    // }
 
     /* zero out .bss section */
     for( uint32_t * dest = &_sbss; dest < &_ebss; )
diff --git a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/scripts/mps2_m3.ld b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/scripts/mps2_m3.ld
index e3dee7e4..47644818 100644
--- a/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/scripts/mps2_m3.ld
+++ b/FreeRTOS/Demo/CORTEX_M3_MPS2_QEMU_GCC/scripts/mps2_m3.ld
@@ -26,15 +26,14 @@
 
 MEMORY
 {
-    FLASH (xr) : ORIGIN = 0x00000000, LENGTH = 4M /* to 0x00003FFF = 0x007FFFFF*/
-    RAM (xrw)  : ORIGIN = 0x20000000, LENGTH = 4M /* to 0x21FFFFFF = 0xFFFFFF */
+    FLASH (xrw) : ORIGIN = 0x00000000, LENGTH = 4M /* to 0x00003FFF = 0x007FFFFF*/
 }
 ENTRY(Reset_Handler)
 
 _Min_Heap_Size = 0x300000 ;        /* Required amount of heap. */
 _Min_Stack_Size = 0x4000 ;       /* Required amount of stack. */
 M_VECTOR_RAM_SIZE = (16 + 48) * 4;
-_estack = ORIGIN(RAM) + LENGTH(RAM);
+_estack = ORIGIN(FLASH) + LENGTH(FLASH);
 
 SECTIONS
 {
@@ -85,7 +84,7 @@ SECTIONS
         . += M_VECTOR_RAM_SIZE;
         . = ALIGN(4);
         __interrupts_ram_end = .;
-    } > RAM
+    } > FLASH
 
     _sidata = LOADADDR(.data);
 
@@ -96,7 +95,7 @@ SECTIONS
         *(.data*)
         . = ALIGN(4);
         _edata = .;
-    } > RAM AT > FLASH
+    } > FLASH
 
     .uninitialized (NOLOAD):
     {
@@ -106,7 +105,7 @@ SECTIONS
         KEEP(*(.keep.uninitialized))
         . = ALIGN(32);
         __uninitialized_end = .;
-    } > RAM
+    } > FLASH
 
     .bss :
     {
@@ -118,7 +117,7 @@ SECTIONS
         . = ALIGN(4);
         _ebss = .;
         __bss_end__ = _ebss;
-    } >RAM
+    } >FLASH
 
     .heap :
     {
@@ -130,11 +129,11 @@ SECTIONS
         _heap_top = .;
         . = . + _Min_Stack_Size;
         . = ALIGN(8);
-       } >RAM
+       } >FLASH
 
    /* Set stack top to end of RAM, and stack limit move down by
     * size of stack_dummy section */
-   __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+   __StackTop = ORIGIN(FLASH) + LENGTH(FLASH);
    __StackLimit = __StackTop - _Min_Stack_Size;
    PROVIDE(__stack = __StackTop);