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 <[EMAIL PROTECTED]>
To: wang cui <[EMAIL PROTECTED]>
CC: [email protected]
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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