DC32 Instruction

[markbell9]

Posted on May 18, 2012 at 21:45

 Hello --

We're trying to bring up FreeRTOS on our STM32F103c8 micro.

In the function vPortStartFirstTask (file portasm.s) there is an SVC call as follows:

cpsie i

    0x8002efe: 0xb662         CPSIE     i

 svc 0

    0x8002f00: 0xdf00         SVC          &sharp0x0

    0x8002f02: 0x0000         MOVS      r0, r0

_?0:

    0x8002f04: 0x200002e8     DC32      pxCurrentTCB

_?1:

    0x8002f08: 0xe000ed08     DC32      VTOR

Immediately after the last assembler statement I end up in the HardFault_Handler.

I know what pxCurrentTCB and VTOR are,  but I can not find what the DC32 means.

Thank you

Mark

#stm32

[Tesla DeLorean]

Posted on May 18, 2012 at 21:54

Define Constant

Keil/Realview uses DCD

__Vectors DCD __initial_sp ; Top of Stack
DCD Reset_Handler ; Reset Handler
DCD NMI_Handler ; NMI Handler
DCD HardFault_Handler ; Hard Fault Handler
...

ARM can't load large immediate constants, the assembler places them in ''Literal Pools'' usually past the end of a subroutine, and accesses them with LDR PC Relative instructions.