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Change assembly sequence to avoid changing APSR

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Change assembly sequence that starts the Nordic bootloader to remove
MOV instruction before cheks of IPSR. The MOV might be translated into a ADDS
that could change the APSR and cause a wrong branch to be taken.
This commit is contained in:
Andres Amaya Garcia 2015-11-13 09:42:12 +00:00
parent 90f6c9714f
commit c8cb3aeee3
1 changed files with 2 additions and 2 deletions
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4
source/nordic-sdk/components/libraries/bootloader_dfu/bootloader_util_arm.c
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@ -59,10 +59,10 @@ EXC_RETURN_CMD EQU 0xFFFFFFF9 ; EXC_RETURN for ARM Cortex. When loaded to PC t
MSR MSP, R5 ; Set the main stack pointer to the applications MSP.
LDR R6, [R0, #0x04] ; Load Reset handler into register 6.
MOV R0, R6
LDR R2, =MASK_ZEROS ; Load zeros to R2
MRS R3, IPSR ; Load IPSR to R3 to check for handler or thread mode
CMP R2, R3 ; Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader
MOV R0, R6
BNE isr_abort ; If not zero we need to exit current ISR and jump to reset handler of bootloader
LDR R4, =MASK_ONES ; Load ones to R4 to be placed in Link Register.
@ -98,9 +98,9 @@ static void bootloader_util_reset(uint32_t start_addr)
"MSR MSP, r5 \n\t" /* Set the main stack pointer to the applications MSP. */
"LDR r6,[r0, #0x04] \n\t" /* Load Reset handler into register 0. */
"MOV R0, R6 \n\t"
"LDR r2, =MASK_ZEROS\n\t" /* Load zeros to R2 */
"MRS r3, IPSR \n\t" /* Load IPSR to R3 to check for handler or thread mode */
"MOV R0, R6 \n\t"
"CMP r2, r3 \n\t" /* Compare, if 0 then we are in thread mode and can continue to reset handler of bootloader */
"BNE isr_abort \n\t" /* If not zero we need to exit current ISR and jump to reset handler of bootloader */