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SWI Interrupt

2006-01-22 by Balajee Premraj

Hi All,

I have this reference software code downloaded from
Keil website for interrupt driven Serial IO.

The software code uses SWI interrupt 8 and 9 for the
routines com_putchar() and com_getchar()

I added the swi_vec.s file into the project directory
and built the code.

However it does not seem to be working and on
debugging the code, i found that, printf , library
call uses SWI 8, 

it goes to the SWI_vec.s files, SWI_handler, and from
there the code gets looped inifinetly in b $ loop.


The keil linker should create a SWI table entry
automatically and fill in the SWI Table, Disassembling
the linker generated .cod file, i dont see this table
entry to be updated with the SWI 8 and SWI 9
functions.

How do i get the keil linker tool to update these
entries automatically.



These are the definitions

int com_putchar (int c) __swi(8)
int com_getchar (void) __swi(9)


swi_vec.s

/***********************************************************************/
/*  This file is part of the CA ARM C Compiler package
                */
/*  Copyright KEIL ELEKTRONIK GmbH 2002 - 2004        
                */
/***********************************************************************/
/*                                                    
                */
/*  SWI_VEC.S:  Pre-defined vectored interrupt handler
SWI interrupt   */
/*                                                    
                */
/***********************************************************************/

AREA ?C?SWI, CODE, READONLY, ALIGN=2

PUBLIC SWI_Handler?A, ?SWI?Table, ?SWI?Empty

SWI_Handler?A    PROC CODE32
        STMFD   SP!,{LR}           ; Store LR register
        MRS     R8,SPSR
        TST     R8,#0x20           ; SWI call from 
        LDRNEH  R8,[LR,#-2]        ; Thumb: Load
halfword instruction
        ANDNE   R8,R8,#0xFF        ;        extract
SWI number
        LDREQ   R8,[LR,#-4]        ; ARM:   Load word 
   instruction
        BICEQ   R8,R8,#0xFF000000  ;        extract
SWI number
                                   ; R4 now contains
SWI number
; SWI Handler
;       LDR     R12,[PC,#(?SWI?Table-$-8)] ; Maximum
number of interrupts
;       LDR     R12,[PC,#0x24]     ; Maximum number of
interrupts
        ADR     R12,?SWI?Table
        LDR     R12,[R12]          ; load last
SWI-Function-number

        CMP     R8,R12                                
            
        BGT     ?SWI?Empty         ; overflow
        ADR     R12,?SWI?Table+4
        LDR     R12,[R12,R8,LSL #2]; SWI function
address
        MOV     LR,PC              ; Return address
        BX      R12                ; Call SWI function

        LDMFD   SP!,{PC}^          ; Return

?SWI?Empty:
        B       $                  ; no existing SWI

; *** DO NOT MODIFY THIS PORTION OF THE FILE ***
?SWI?Table:                        ; Marker for LA
Linker                       
; 
; The LA Linker inserts at this label
;       DD      0                  ; <last SWI
function number>
;       DD      ?SWI?Empty         ; <entry for SWI
function 0>
;       DD      <SWI entry 1>
;       DD      <SWI entry 2>
;       DD           :
; For non-existing SWI functions DD ?SWI?Empty is
inserted

        ENDP

        END


After the compilation , i dont see this ?SWI?Table 
entry to be updated with the corresponding interrupt
functions.


Any help would be greatly appreciated.


Thanks,Balajee


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Re: SWI Interrupt

2006-01-23 by theothervmax

Hi,
in the "startup.s" check out this constant:

SVC_Stack_Size  EQU     0x..........

and if it equals 4 or so, try to increase this value to have enough 
stack size in supervisor mode.

Regards, 
Max


--- In lpc2000@yahoogroups.com, Balajee Premraj <balajee_78@y...> 
wrote:
>
> Hi All,
> 
> I have this reference software code downloaded from
> Keil website for interrupt driven Serial IO.
> 
> The software code uses SWI interrupt 8 and 9 for the
> routines com_putchar() and com_getchar()
> 
> I added the swi_vec.s file into the project directory
> and built the code.
> 
> However it does not seem to be working and on
> debugging the code, i found that, printf , library
> call uses SWI 8, 
> 
> it goes to the SWI_vec.s files, SWI_handler, and from
> there the code gets looped inifinetly in b $ loop.
> 
> 
> The keil linker should create a SWI table entry
> automatically and fill in the SWI Table, Disassembling
> the linker generated .cod file, i dont see this table
> entry to be updated with the SWI 8 and SWI 9
> functions.
> 
> How do i get the keil linker tool to update these
> entries automatically.
> 
> 
> 
> These are the definitions
> 
> int com_putchar (int c) __swi(8)
> int com_getchar (void) __swi(9)
> 
> 
> swi_vec.s
> 
> /******************************************************************
*****/
> /*  This file is part of the CA ARM C Compiler package
>                 */
> /*  Copyright KEIL ELEKTRONIK GmbH 2002 - 2004        
>                 */
> /******************************************************************
*****/
> /*                                                    
>                 */
> /*  SWI_VEC.S:  Pre-defined vectored interrupt handler
> SWI interrupt   */
> /*                                                    
>                 */
> /******************************************************************
*****/

Show quoted textHide quoted text

> 
> AREA ?C?SWI, CODE, READONLY, ALIGN=2
> 
> PUBLIC SWI_Handler?A, ?SWI?Table, ?SWI?Empty
> 
> SWI_Handler?A    PROC CODE32
>         STMFD   SP!,{LR}           ; Store LR register
>         MRS     R8,SPSR
>         TST     R8,#0x20           ; SWI call from 
>         LDRNEH  R8,[LR,#-2]        ; Thumb: Load
> halfword instruction
>         ANDNE   R8,R8,#0xFF        ;        extract
> SWI number
>         LDREQ   R8,[LR,#-4]        ; ARM:   Load word 
>    instruction
>         BICEQ   R8,R8,#0xFF000000  ;        extract
> SWI number
>                                    ; R4 now contains
> SWI number
> ; SWI Handler
> ;       LDR     R12,[PC,#(?SWI?Table-$-8)] ; Maximum
> number of interrupts
> ;       LDR     R12,[PC,#0x24]     ; Maximum number of
> interrupts
>         ADR     R12,?SWI?Table
>         LDR     R12,[R12]          ; load last
> SWI-Function-number
> 
>         CMP     R8,R12                                
>             
>         BGT     ?SWI?Empty         ; overflow
>         ADR     R12,?SWI?Table+4
>         LDR     R12,[R12,R8,LSL #2]; SWI function
> address
>         MOV     LR,PC              ; Return address
>         BX      R12                ; Call SWI function
> 
>         LDMFD   SP!,{PC}^          ; Return
> 
> ?SWI?Empty:
>         B       $                  ; no existing SWI
> 
> ; *** DO NOT MODIFY THIS PORTION OF THE FILE ***
> ?SWI?Table:                        ; Marker for LA
> Linker                       
> ; 
> ; The LA Linker inserts at this label
> ;       DD      0                  ; <last SWI
> function number>
> ;       DD      ?SWI?Empty         ; <entry for SWI
> function 0>
> ;       DD      <SWI entry 1>
> ;       DD      <SWI entry 2>
> ;       DD           :
> ; For non-existing SWI functions DD ?SWI?Empty is
> inserted
> 
>         ENDP
> 
>         END
> 
> 
> After the compilation , i dont see this ?SWI?Table 
> entry to be updated with the corresponding interrupt
> functions.
> 
> 
> Any help would be greatly appreciated.
> 
> 
> Thanks,Balajee
> 
> 
> __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around 
> http://mail.yahoo.com
>

Lpc2000

SWI Interrupt

SWI Interrupt

Re: SWI Interrupt

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