50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
#include <stdlib.h>
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#include <stm32f4xx.h>
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#include "misc.h"
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#include "mpconfig.h"
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#include "qstr.h"
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#include "obj.h"
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#include "pendsv.h"
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static mp_obj_t pendsv_object = MP_OBJ_NULL;
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void pendsv_init(void) {
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// set PendSV interrupt at lowest priority
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NVIC_SetPriority(PendSV_IRQn, 0xff);
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}
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// call this function to raise a pending exception during an interrupt
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// it will wait until all interrupts are finished then raise the given
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// exception object using nlr_jump in the context of the top-level thread
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void pendsv_nlr_jump(mp_obj_t o) {
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pendsv_object = o;
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SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
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}
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void pendsv_isr_handler(void) {
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// re-jig the stack so that when we return from this interrupt handler
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// it returns instead to nlr_jump with argument pendsv_object
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__asm volatile (
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"ldr r0, pendsv_object_ptr\n"
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"ldr r0, [r0]\n"
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"str r0, [sp, #0]\n"
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"ldr r0, nlr_jump_ptr\n"
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"str r0, [sp, #24]\n"
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"bx lr\n"
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".align 2\n"
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"pendsv_object_ptr: .word pendsv_object\n"
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"nlr_jump_ptr: .word nlr_jump\n"
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);
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/*
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sp[0] = r0 = exception to raise
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sp[6] = pc = nlr_jump
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uint32_t x[2] = {0x424242, 0xdeaddead};
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printf("PendSV: %p\n", x);
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for (uint32_t *p = (uint32_t*)(((uint32_t)x - 15) & 0xfffffff0), i = 64; i > 0; p += 4, i -= 4) {
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printf(" %p: %08x %08x %08x %08x\n", p, p[0], p[1], p[2], p[3]);
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}
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*/
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}
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