Hi,
In my Cortex-M0 project, there are two program images residing at different memory locations: 0x0000_0000 and 0x0010_0000. Each program has its own vector table. M0 will boot from the program at 0x0010_0000 then switch to the other program (0x0000_0000) at the end.
What is the correct way to switch to the porgram at 0x0000_0000? I'm not sure whether the following instructions are correct or not.
LDR R6, =0x1 ; set R6 to 0x0000_0001 due to Thumb mode
LDR R0, [R6]
MOV SP, R0
LDR R1, [R6, #4]
BX R1
Can someone please point me the right implementation? Thanks a lot.
I think forgot that you're using Cortex-M0 for a while, sorry about that. To fix the ldr sp,[r0], you'll just need to do for instance...
movs r0,#0
ldr r1,=SC
str r0,[r1,#VTOR]
ldr r1,[r0]
mov sp,r1
ldr r1,[r0,#4]
bx r1
... I believe that should fix it. The shorter version, probably won't be fixable; I guess I got too used to Cortex-M3/Cortex-M4.
Yes I'm using Cortex-M0. So there is no VTOR in the System Control block. This leads to the compiling error of these two lines,,,
According to the documentation, on Cortex-M0, the exception vector table is fixed at address 0x00000000.
However, since a vendor can customize the behaviour of virtually anything, I know of one implementation, which allows you to change it, though; perhaps there are more.
Fortunately, Cortex-M0+ has a VTOR.
Which device in particular are you writing code for ?
Cortex-M0, not Cortex-M0+.