Skip to content

Move interrupts to bootloader when IVSEL is set #546

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

Move interrupts to bootloader when IVSEL is set #546

Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
acb73a9
Move the interrupt table to the bootloader sector when IVSEL is set
emanuelen5 Nov 12, 2024
f22aef3
Break out into function
emanuelen5 Nov 15, 2024
b80b39f
Calculate boot size for ATmega328 based on fuses
emanuelen5 Nov 15, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
34 changes: 33 additions & 1 deletion simavr/sim/sim_interrupts.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
#include "sim_interrupts.h"
#include "sim_avr.h"
#include "sim_core.h"
#include "sim_core_declare.h"

DEFINE_FIFO(avr_int_vector_p, avr_int_pending);

Expand Down Expand Up @@ -226,6 +227,37 @@ avr_interrupt_reti(
table->running[table->running_ptr-1]->vector : 0);
}

static int bootloader_size_avr328(avr_t *avr)
{
const char efuse = avr->fuse[2];
const char bootsz = (efuse >> 1) & 0x3;

switch (bootsz)
{
case 0:
return 256 * 2;
case 1:
return 512 * 2;
case 2:
return 1024 * 2;
default:
return 2048 * 2;
}
}

static int interrupt_table_offset(avr_t *avr)
{
const int mcucr = _SFR_IO8(0x35);
const int ivsel = 1;
const char interrupt_sector_moved_to_bootloader = avr->data[mcucr] & (1 << ivsel);

const int flash_size = avr->flashend + 1;
if (interrupt_sector_moved_to_bootloader)
return flash_size - bootloader_size_avr328(avr);

return 0;
}

/*
* check whether interrupts are pending. If so, check if the interrupt "latency" is reached,
* and if so triggers the handlers and jump to the vector.
Expand Down Expand Up @@ -281,7 +313,7 @@ avr_service_interrupts(
printf("IRQ%d calling\n", vector->vector);
_avr_push_addr(avr, avr->pc);
avr_sreg_set(avr, S_I, 0);
avr->pc = vector->vector * avr->vector_size;
avr->pc = vector->vector * avr->vector_size + interrupt_table_offset(avr);

avr_raise_irq(vector->irq + AVR_INT_IRQ_RUNNING, 1);
avr_raise_irq(table->irq + AVR_INT_IRQ_RUNNING, vector->vector);
Expand Down