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cpu/cortexm_common: fix r12 clobber in pendsv for Cortex-M3+

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Kaspar Schleiser 2020-12-08 11:17:24 +01:00
parent 8b8a3ffbd9
commit 04ca147f59
1 changed files with 7 additions and 6 deletions
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13
cpu/cortexm_common/thread_arch.c
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@ -317,20 +317,21 @@ void __attribute__((naked)) __attribute__((used)) isr_pendsv(void) {
/* skip context saving if sched_active_thread == NULL */ /* skip context saving if sched_active_thread == NULL */
"ldr r1, =sched_active_thread \n" /* r1 = &sched_active_thread */ "ldr r1, =sched_active_thread \n" /* r1 = &sched_active_thread */
"ldr r12, [r1] \n" /* r12 = sched_active_thread */ "push {r4, lr} \n" /* push r4 and exception return code */
"push {lr} \n" /* push exception return code */ "ldr r4, [r1] \n" /* r4 = sched_active_thread */
"cpsid i \n" /* Disable IRQs during sched_run */ "cpsid i \n" /* Disable IRQs during sched_run */
"bl sched_run \n" /* perform scheduling */ "bl sched_run \n" /* perform scheduling */
"cpsie i \n" /* Re-enable interrupts */ "cpsie i \n" /* Re-enable interrupts */
"cmp r0, r12 \n" /* if r0 == 0: (no switch required) */ "cmp r0, r4 \n" /* if r0 == r1: (new thread == old
thread, no switch required) */
"it eq \n" "it eq \n"
"popeq {pc} \n" /* Pop exception to pc to return */ "popeq {r4, pc} \n" /* Pop exception to pc to return */
"pop {lr} \n" /* Pop exception from the exception stack */ "mov r1, r4 \n" /* save sched_active_thread in r1 */
"pop {r4, lr} \n" /* Pop exception from the exception stack */
"mov r1,r12 \n" /* r1 = sched_active_thread */
"cbz r1, restore_context \n" /* goto restore_context if r1 == 0 */ "cbz r1, restore_context \n" /* goto restore_context if r1 == 0 */
"mrs r2, psp \n" /* get stack pointer from user mode */ "mrs r2, psp \n" /* get stack pointer from user mode */