1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
#include <stdlib.h>
#include <stm32f4xx.h>
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "pendsv.h"
static mp_obj_t pendsv_object = MP_OBJ_NULL;
void pendsv_init(void) {
// set PendSV interrupt at lowest priority
NVIC_SetPriority(PendSV_IRQn, 0xff);
}
// call this function to raise a pending exception during an interrupt
// it will wait until all interrupts are finished then raise the given
// exception object using nlr_jump in the context of the top-level thread
void pendsv_nlr_jump(mp_obj_t o) {
pendsv_object = o;
SCB->ICSR = SCB_ICSR_PENDSVSET_Msk;
}
void pendsv_isr_handler(void) {
// re-jig the stack so that when we return from this interrupt handler
// it returns instead to nlr_jump with argument pendsv_object
__asm volatile (
"ldr r0, pendsv_object_ptr\n"
"ldr r0, [r0]\n"
"str r0, [sp, #0]\n"
"ldr r0, nlr_jump_ptr\n"
"str r0, [sp, #24]\n"
"bx lr\n"
".align 2\n"
"pendsv_object_ptr: .word pendsv_object\n"
"nlr_jump_ptr: .word nlr_jump\n"
);
/*
sp[0] = r0 = exception to raise
sp[6] = pc = nlr_jump
uint32_t x[2] = {0x424242, 0xdeaddead};
printf("PendSV: %p\n", x);
for (uint32_t *p = (uint32_t*)(((uint32_t)x - 15) & 0xfffffff0), i = 64; i > 0; p += 4, i -= 4) {
printf(" %p: %08x %08x %08x %08x\n", p, p[0], p[1], p[2], p[3]);
}
*/
}
|
