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Hi guys,
I'm wishing to move the location of the stack but how is this possible? In the startup.s I have
EXPORT __initial_sp Stack_Size EQU 0x00000200 AREA STACK, NOINIT, READWRITE, ALIGN=3 Stack_Mem SPACE Stack_Size __initial_sp
However there's no option for the location and nothing specific for the stack appears to show up in the generate scatter file.
I'm a little lost and would appreciate any help.
Many thanks
Thank you for the response.
In my situation I'll be setting up both a main and process stack where resident bootloader code and interrupts will run in the main stack and application code in the process stack.
I am using an NXP Cortex-M0 chip and so am relocating my vector table to RAM and plan on using the remaining space in the relocated 512B to store the main stack, leaving all remaining memory to the application and its process stack.
My issue is in placing the start of the stack at the end of this 512B block. I have attempted to reserve space for the vector table (amongst other items) using code like this:
AREA VECTORS, NOINIT, DATA, READWRITE ; Reserve space for vector table in RAM SPACE 0xBC
However the stack always seems to locate its start at 0x0 + stacksize, as opposed to at the far end of the 512B block. I could just change the size of the stack to 0x200 perhaps, however if I ever used a heap etc this would mess-up any heap-stack collision detection.
Any ideas?
Deconvoluting a little of what I said, here's my ASM code:
; Vector Table Mapped to Address 0 at Reset AREA RESET, DATA, READONLY EXPORT __Vectors __Vectors DCD __initial_sp ; Top of Stack DCD Reset_Handler ; Reset Handler DCD NMI_Handler ; NMI Handler DCD HardFault_Handler ; Hard Fault Handler DCD 0 ; Reserved DCD 0 ; Reserved DCD 0 ; Reserved DCD 0 ; Reserved DCD 0 ; Reserved DCD 0 ; Reserved DCD 0 ; Reserved DCD SVC_Handler ; SVCall Handler DCD 0 ; Reserved DCD 0 ; Reserved DCD PendSV_Handler ; PendSV Handler DCD SysTick_Handler ; SysTick Handler ; External Interrupts DCD WAKEUP_IRQHandler ; 12 wakeup sources for all the DCD WAKEUP_IRQHandler ; I/O pins starting from PIO0 (0:11) DCD WAKEUP_IRQHandler ; all 40 are routed to the same ISR DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD WAKEUP_IRQHandler DCD I2C_IRQHandler ; I2C DCD TIMER16_0_IRQHandler ; 16-bit Timer0 DCD TIMER16_1_IRQHandler ; 16-bit Timer1 DCD TIMER32_0_IRQHandler ; 32-bit Timer0 DCD TIMER32_1_IRQHandler ; 32-bit Timer1 DCD SSP_IRQHandler ; SSP DCD UART0_IRQHandler ; UART0 DCD UART1_IRQHandler ; UART1 DCD COMP_IRQHandler ; Comparator DCD ADC_IRQHandler ; A/D Converter DCD WDT_IRQHandler ; Watchdog timer DCD BOD_IRQHandler ; Brown Out Detect DCD FMC_IRQHandler ; IP2111 Flash Memory Controller DCD PIOINT0_IRQHandler ; PIO INT0 DCD PIOINT1_IRQHandler ; PIO INT1 DCD PIOINT2_IRQHandler ; PIO INT2 DCD PMU_IRQHandler ; PMU/Wakeup DCD DMA_IRQHandler ; DMA DCD RTC_IRQHandler ; RTC AREA VECTORS, NOINIT, DATA, READWRITE ; Reserve space for vector table in RAM SPACE 0xBC AREA FIRMWARE, NOINIT, DATA, READWRITE ; Reserve space for Firmware Flashing in RAM EXPORT __UpdateBuffer __UpdateBuffer SPACE 0x80 ; Reserve 128B of space as a firmware update buffer ; <h> Stack Configuration ; <o> Stack Size (in Bytes) <0x0-0xFFFFFFFF:8> ; </h> EXPORT __initial_sp Stack_Size EQU 0x00000147 AREA STACK, NOINIT, READWRITE, ALIGN=3 Stack_Mem SPACE Stack_Size __initial_sp END
As it stands, the start of the stack is always the same as the Stack_Size, in this case 0x147. I instead want it at 0x1FF with a size of 0x147. As you can see I'm attempting to reserve space, however it's not working so well.
Have you considered a scatter file for specifying where you want to locate different AREAs?
Yes, I will ultimately do this if I have no choice but I was hoping to keep within the default uVision layout - this is so that those who come after me will have less of a learning curve and the software is easier to maintain.
It feels as though I should be able to reserve a block of space within an area without having to resort to scatter files.
One thing I can say form all of this is that the scatter-file/memory allocation system in uVision could do with a rethink and overhaul. Ideally you want scatter file editing to be natively possible, as it seems, for me at least, I almost always end up having to implement my own.