Convert GCC ARM to ADS ARM C source.

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yodathegreat

Joined: 23 Feb 2002
Posts: 56
Helped: 1

21 Aug 2004 16:53 c2076e

Hi all,

How to convert this GCC code to ADS ARM C code ?.

best regards

#define portSAVE_CONTEXT() \
{ \
extern volatile void * volatile pxCurrentTCB; \
\
/* Push R0 as we are going to use the register. */ \
asm volatile ( "STMDB SP!, {R0}" ); \
\
/* Set R0 to point to the task stack pointer. */ \
asm volatile ( "STMDB SP,{SP}^" ); \
asm volatile ( "SUB SP, SP, #4" ); \
asm volatile ( "LDMIA SP!,{R0}" ); \
\
/* Push the return address onto the stack. */ \
asm volatile ( "STMDB R0!, {LR}" ); \
\
/* Now we have saved LR we can use it instead of R0. */ \
asm volatile ( "MOV LR, R0" ); \
\
/* Pop R0 so we can save it onto the system mode stack. */ \
asm volatile ( "LDMIA SP!, {R0}" ); \
\
/* Push all the system mode registers onto the task stack. */ \
asm volatile ( "STMDB LR,{R0-LR}^"); \
asm volatile ( "SUB LR, LR, #60" ); \
\
/* Push the SPSR onto the task stack. */ \
asm volatile ( "MRS R0, SPSR" ); \
asm volatile ( "STMDB LR!, {R0}" ); \
\
/* Store the new top of stack for the task. */ \
asm volatile ( "LDR R0, %0" : : "m" (pxCurrentTCB) ); \
asm volatile ( "STR LR, [R0]" ); \
}

dainis

Joined: 15 May 2001
Posts: 1451
Helped: 56

22 Aug 2004 19:28 convert c to arm

ADS have this sintax of inline asm

#define SWI_SHOWREGS __asm {swi 0x0000004}

__asm { MRC P15, 0, i, c0, c0; }

yodathegreat

Joined: 23 Feb 2002
Posts: 56
Helped: 1

23 Aug 2004 0:22 __asm arm sp

Hi Dainis,

i know the __asm.

but the problem is SP !! in inline asm ADS impossible to use SP register..

best regards

dainis wrote:

@DS have this sintax of inline asm

#define SWI_SHOWREGS __asm {swi 0x0000004}

__asm { MRC P15, 0, i, c0, c0; }

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23 Aug 2004 0:22 Ads

dainis

Joined: 15 May 2001
Posts: 1451
Helped: 56

23 Aug 2004 7:25 __asm__ __volatile__ ldmia

yodathegreat wrote:

Hi Dainis,

i know the __asm.

but the problem is SP !! in inline asm @DS impossible to use SP register..

best regards

dainis wrote:

@DS have this sintax of inline asm

#define SWI_SHOWREGS __asm {swi 0x0000004}

__asm { MRC P15, 0, i, c0, c0; }

It is impossible change SP from inline asm ....
Maybe is possible insert code via __asm and define opcode as bianry data ???

C2076E: illegal write to SP
Example:
__asm{ mov sp,#0x4000; }

You must never try to change the Stack Pointer (sp=r13) using the inline assembler, because the
compiler requires full control of the stack for its operation, therefore writing to the SP is not
allowed. The compiler will stack/restore any working registers as required automatically.

artem

Joined: 22 May 2003
Posts: 1652
Helped: 91
Location: Turan

23 Aug 2004 10:07 __asm gcc arm

The problem here is that macro functionality is part of RTOS proting code where task switch is done . So SP is used legally . From other side the function can not be simply rewritten without modification as asm file and linked to c files as macro is expanded as inline file which means no stack usage at function call . and there is another reason - different register usage for fucntion calls due to different compilers .