Other Parts Discussed in Thread: OMAPL138
Hi
I am now programming on omapl138 using CCSV5.2.1. I want to declare and initialize three stacks: SVC, FIQ and IRQ stacks for the following use. I was thinking I can declare and initialize them in my own startup codes, which would run before _c_int00. So in addition to my current project, which was created as a general C/C++ CCS project with all default .cmd and link settings, I added another file initstack.asm, which is
;**********************************************
; Global symbols defined here
.global _c_int00
.global _init_stack
;***********************************************
; define SVC stack, FIQ stack and IRQ stack
__SVC_STACK_SIZE:.set 0x1000
__IRQ_STACK_SIZE:.set 0x1000
__FIQ_STACK_SIZE:.set 0x1000
__svc_stack:.usect ".svcstack", __SVC_STACK_SIZE, 4
__irq_stack:.usect ".irqstack", __IRQ_STACK_SIZE, 4
__fiq_stack:.usect ".fiqstack", __FIQ_STACK_SIZE, 4
;***********************************************
; define function _init_stack
_init_stack:.asmfunc
; switch to SVC mode
MRS R0,CPSR
BIC R0,R0,#0x1f
ORR R0,R0,#0x13
MSR CPSR_cf,R0
; initialize svc stack
LDR SP, svc_stack
LDR R0, SVC_STACK_SIZE
ADD SP,SP,R0
; switch to IRQ mode
MRS R0,CPSR
BIC R0,R0,#0x1f
ORR R0,R0,#0x12
MSR CPSR_cf,R0
; initialize irq stack
LDR SP, irq_stack
LDR R0, IRQ_STACK_SIZE
ADD SP,SP,R0
; switch to fiq mode
MRS R0,CPSR
BIC R0,R0,#0x1f
ORR R0,R0,#0x11
MSR CPSR_cf, R0
; initialize fiq stack
LDR SP, fiq_stack
LDR R0, FIQ_STACK_SIZE
ADD SP, SP,R0
;jump to _c_int00
LDR PC,c_int00
.endasmfunc
;***********************************************
;constant used in this module
c_int00 .long _c_int00
SVC_STACK_SIZE .long __SVC_STACK_SIZE
IRQ_STACK_SIZE .long __IRQ_STACK_SIZE
FIQ_STACK_SIZE .long __FIQ_STACK_SIZE
svc_stack .long __svc_stack
irq_stack .long __irq_stack
fiq_stack .long __fiq_stack
And in .cmd file, I include these three stacks like this:
...
/* stack sections */
.svcstack > SHRAM
.irqstack > SHRAM
.fiqstack > SHRAM
...
With above change, compile and link can all be done successfully. However, after I downloaded it into omapl138 using xds100v2, it seems that _init_stack was not executed and I could not find section .svcstack, .irqstack and .fiqstack in the memory. What's more, even without downloading it, I opened the .map file, which is generated in the link process, where I could not find _init_stack module neither.
In my project, .asm is the only asm file, and it was complied successfully because I do can find a .obj file under that folder, but it seems that this compiled module was not linked with other part in my project.
So I was wondering how can I include my own startup codes in my project and have it run before _c_int00?
Thanks
Fu
