Re: [ECOS] Patch for packages\hal\arm\arch\current\src\vectors.S

["wang cui" <iucgnaw at msn dot com>]

Thanks for your reply, I just think we should provide a compatible way(a 
confituration option is a good idea) to meet the LPC2XXX requirement in the 
vectors.S. Then we need not to modified it everytime after synchronize with 
CVS.


> From: Gary Thomas <gary@mlbassoc.com>
> To: wang cui <iucgnaw@msn.com>
> CC: ecos-discuss@ecos.sourceware.org
> Subject: Re: [ECOS] Patch for packages\hal\arm\arch\current\src\vectors.S
> Date: Fri, 25 Aug 2006 06:03:24 -0600
>
> wang cui wrote:
> > According to LPC2XXX datasheet, checksum of all 8 vectors value must be
> > zero, which means Reserved Vector value must be the inversed value of
> > sum of other 7 vectors value, so we must compute it before compile and
> > place the hardnumber in it.
> >
> > Actually, when download hex file to LPC2XXX board through ISP, if the
> > Reserved Vector is not valid, the ISP program changes this vector to a
> > checksum number automatically, and cause error when verify the flash.
> > So I modified the vectors.s to resolve it.
> >
> > ***current code***
> >        .global __exception_handlers
> > __exception_handlers:
> > #ifdef CYGSEM_HAL_ROM_RESET_USES_JUMP
> > // Assumption:  ROM code has these vectors at the hardware reset 
address.
> > // A simple jump removes any address-space dependencies [i.e. safer]
> >        b       reset_vector                    // 0x00
> > #else               ldr     pc,.reset_vector                // 0x00
> > #endif               ldr     pc,.undefined_instruction       // 0x04
> >        ldr     pc,.software_interrupt          // 0x08 start && 
software
> > int
> >        ldr     pc,.abort_prefetch              // 0x0C
> >        ldr     pc,.abort_data                  // 0x10
> >        .word   0                               // unused
> >        ldr     pc,.IRQ                         // 0x18
> >        ldr     pc,.FIQ                         // 0x1C
> >
> > ***modified code***
> >        .global __exception_handlers
> > __exception_handlers:
> > #ifdef CYGSEM_HAL_ROM_RESET_USES_JUMP
> > // Assumption:  ROM code has these vectors at the hardware reset 
address.
> > // A simple jump removes any address-space dependencies [i.e. safer]
> >        b       reset_vector                    // 0x00
> > #else               ldr     pc,.reset_vector                // 0x00
> > #endif               ldr     pc,.undefined_instruction       // 0x04
> >        ldr     pc,.software_interrupt          // 0x08 start && 
software
> > int
> >        ldr     pc,.abort_prefetch              // 0x0C
> >        ldr     pc,.abort_data                  // 0x10
> > #ifdef CYGPKG_HAL_ARM_LPC2XXX
> > #ifdef CYGSEM_HAL_ROM_RESET_USES_JUMP
> >        .word   0xB4405F62                      // checksum of other 
vectors
> > #else               .word   0xB8A06F58                      // checksum
> > of other vectors
> > #endif        #else
> >        .word   0                               // unused
> > #endif
> >        ldr     pc,.IRQ                         // 0x18
> >        ldr     pc,.FIQ                         // 0x1C
> >
> > Should it be patched ?
>
> If you need this value in there to make it work, then yes, there
> should be a patch.  However, we can't have "#ifdef CYGPKG_HAL_ARM_LPC2XXX"
> in there as "vectors.S" should be target independent, i.e. no #if 
statements
> that depend on platform or family - that's just the eCos philosophy.
>
> I'd do it something like this:
>
> #ifdef CYGINT_HAL_ARM_VECTOR_0x14
> 	.word CYGINT_HAL_ARM_VECTOR_0x14
> #else
> 	.word 0
> #endif
>
> Then, define CYGINT_HAL_ARM_VECTOR_0x14 in the target/platform specific 
files
> for the LPC2XXX.
>
> The other problem I see is that this may not be constant as you have made 
it.
> Would it not change if the various other vector handlers move around, i.e.
> if 'abort_data' changes address, etc?  Would it not need to be 
[re]calculated?
> --
> ------------------------------------------------------------
> Gary Thomas                 |  Consulting for the
> MLB Associates              |    Embedded world
> ------------------------------------------------------------
>
> --
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> and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss



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