diff options
Diffstat (limited to 'sem4/embedded/emb_m4/jrnl')
| -rw-r--r-- | sem4/embedded/emb_m4/jrnl/jrnl.ino | 153 | ||||
| -rw-r--r-- | sem4/embedded/emb_m4/jrnl/regs.h | 81 |
2 files changed, 234 insertions, 0 deletions
diff --git a/sem4/embedded/emb_m4/jrnl/jrnl.ino b/sem4/embedded/emb_m4/jrnl/jrnl.ino new file mode 100644 index 0000000..ffd76c9 --- /dev/null +++ b/sem4/embedded/emb_m4/jrnl/jrnl.ino @@ -0,0 +1,153 @@ +#include "regs.h" + +struct tsk { + uint8_t stack_h; + uint8_t stack_l; + + struct tsk *next; +}; + +struct tsk *cur = NULL; +struct tsk *tasks = NULL; + +// Setup a timer running every 10 ms +void timersetup() +{ + noInterrupts(); + + TCNT1 = 0; + + // Enable CTC and set prescaler = 1024. + // This will give a freq of 15625 + TCCR1B = (1 << WGM12) | (1 << CS12) | (1 << CS10); + + // Clear on match + //TCCR1A = (1 << COM1A1); + TCCR1A = 0; + + // Setup compare. Must be around 156 to create 10ms + OCR1A = 156; + + // Enable interrupt on compare + TIMSK1 |= (1 << OCF1A); + + interrupts(); +} + +inline struct tsk *get_next() { + if (cur->next) { + return cur->next; + } + + return tasks; +} + +void create_tsk(struct tsk *t, void (*f)(void), uint8_t *stack, size_t len) { + // Move to the end of stack + uint8_t *s = stack + len - 1; + + // Push load address + *(s--) = (uint16_t)f & 0xFF; + *(s--) = ((uint16_t)f >> 8) & 0xFF; + + // Push all the stuff. Reg + SREG + for (int i = 0; i < 32 + 1; i++) { + *(s--) = 0; + } + + // Save the stack pointer + t->stack_l = (uint16_t)s & 0xFF; + t->stack_h = ((uint16_t)s >> 8) & 0xFF; + + // Put it on the list + t->next = tasks; + tasks = t; +} + +void run() { + cur = tasks; + + // Put it back + SPL = cur->stack_l; + SPH = cur->stack_h; + + POPREGS(); + __asm__("RETI"); +} + +void func(void) { + for(;;) { + Serial.println(1); + } +} +void func3(void) { + for(;;) { + Serial.println(3); + } +} +void func4(void) { + for(;;) { + Serial.println(4); + } +} + +void func2(void) { + bool state = false; + for(;;) { + digitalWrite(13, state); + state = !state; + delay(1000); + } +} + +ISR(TIMER1_COMPA_vect, ISR_NAKED) +{ + PUSHREGS(); + + if (!cur) { + goto exit; + } + + // Save stack space + cur->stack_l = SPL; + cur->stack_h = SPH; + + // Switch + cur = get_next(); + + // Put it back + SPL = cur->stack_l; + SPH = cur->stack_h; + +exit: + + POPREGS(); + __asm__("RETI"); +} + +void setup() +{ + pinMode(13, OUTPUT); + Serial.begin(115200); + + Serial.println("Starting stuff"); + + struct tsk task1, task2, task4, task3; + uint8_t stack[100], stack2[100], stack3[100], stack4[100]; + + timersetup(); + + create_tsk(&task1, func, stack, 100); + create_tsk(&task2, func2, stack2, 100); + create_tsk(&task3, func3, stack3, 100); + create_tsk(&task4, func4, stack4, 100); + + run(); + +} + +void loop() +{ +} + + diff --git a/sem4/embedded/emb_m4/jrnl/regs.h b/sem4/embedded/emb_m4/jrnl/regs.h new file mode 100644 index 0000000..3f6ae03 --- /dev/null +++ b/sem4/embedded/emb_m4/jrnl/regs.h @@ -0,0 +1,81 @@ +#ifndef REGS_H +#define REGS_H + +// Taken from Jens +#define PUSHREGS() __asm__ volatile ( \ + "push r1 \n" \ + "push r0 \n" \ + "in r0, __SREG__ \n" \ + "cli \n" \ + "push r0 \n" \ + "cli \n" \ + "push r2 \n" \ + "push r3 \n" \ + "push r4 \n" \ + "push r5 \n" \ + "push r6 \n" \ + "push r7 \n" \ + "push r8 \n" \ + "push r9 \n" \ + "push r10 \n" \ + "push r11 \n" \ + "push r12 \n" \ + "push r13 \n" \ + "push r14 \n" \ + "push r15 \n" \ + "push r16 \n" \ + "push r17 \n" \ + "push r18 \n" \ + "push r19 \n" \ + "push r20 \n" \ + "push r21 \n" \ + "push r22 \n" \ + "push r23 \n" \ + "push r24 \n" \ + "push r25 \n" \ + "push r26 \n" \ + "push r27 \n" \ + "push r28 \n" \ + "push r29 \n" \ + "push r30 \n" \ + "push r31 \n" \ + ) + +#define POPREGS() __asm__ volatile ( \ + "pop r31 \n" \ + "pop r30 \n" \ + "pop r29 \n" \ + "pop r28 \n" \ + "pop r27 \n" \ + "pop r26 \n" \ + "pop r25 \n" \ + "pop r24 \n" \ + "pop r23 \n" \ + "pop r22 \n" \ + "pop r21 \n" \ + "pop r20 \n" \ + "pop r19 \n" \ + "pop r18 \n" \ + "pop r17 \n" \ + "pop r16 \n" \ + "pop r15 \n" \ + "pop r14 \n" \ + "pop r13 \n" \ + "pop r12 \n" \ + "pop r11 \n" \ + "pop r10 \n" \ + "pop r9 \n" \ + "pop r8 \n" \ + "pop r7 \n" \ + "pop r6 \n" \ + "pop r5 \n" \ + "pop r4 \n" \ + "pop r3 \n" \ + "pop r2 \n" \ + "pop r0 \n" \ + "out __SREG__, r0 \n" \ + "pop r0 \n" \ + "pop r1 \n" \ + ) + +#endif |