git.rot13.org Git - simavr/blob - simavr/sim/sim_interrupts.c

   1 /*
   2         sim_interrupts.c
   3
   4         Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
   5
   6         This file is part of simavr.
   7
   8         simavr is free software: you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 3 of the License, or
  11         (at your option) any later version.
  12
  13         simavr is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License
  19         along with simavr.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <strings.h>
  27 #include "sim_interrupts.h"
  28 #include "sim_core.h"
  29
  30 void avr_register_vector(avr_t *avr, avr_int_vector_t * vector)
  31 {
  32         if (vector->vector) {
  33                 vector->irq.irq = vector->vector;
  34                 avr->vector[vector->vector] = vector;
  35                 if (vector->trace)
  36                         printf("%s register vector %d (enabled %04x:%d)\n", __FUNCTION__, vector->vector, vector->enable.reg, vector->enable.bit);
  37
  38                 if (!vector->enable.reg)
  39                         printf("avr_register_vector: No 'enable' bit on vector %d !\n", vector->vector);
  40         }
  41 }
  42
  43 int avr_has_pending_interrupts(avr_t * avr)
  44 {
  45         return avr->pending[0] || avr->pending[1];
  46 }
  47
  48 int avr_is_interrupt_pending(avr_t * avr, avr_int_vector_t * vector)
  49 {
  50         return avr->pending[vector->vector >> 5] & (1 << (vector->vector & 0x1f));
  51 }
  52
  53 int avr_is_interrupt_enabled(avr_t * avr, avr_int_vector_t * vector)
  54 {
  55         return avr_regbit_get(avr, vector->enable);
  56 }
  57
  58 int avr_raise_interrupt(avr_t * avr, avr_int_vector_t * vector)
  59 {
  60         if (!vector || !vector->vector)
  61                 return 0;
  62         if (vector->trace)
  63                 printf("%s raising %d (enabled %d)\n", __FUNCTION__, vector->vector, avr_regbit_get(avr, vector->enable));
  64         // always mark the 'raised' flag to one, even if the interrupt is disabled
  65         // this allow "pooling" for the "raised" flag, like for non-interrupt
  66         // driven UART and so so. These flags are often "write one to clear"
  67         if (vector->raised.reg)
  68                 avr_regbit_set(avr, vector->raised);
  69
  70         // Mark the interrupt as pending
  71         avr->pending[vector->vector >> 5] |= (1 << (vector->vector & 0x1f));
  72         avr_raise_irq(&vector->irq, 1);
  73
  74         // If the interrupt is enabled, attempt to wake the core
  75         if (avr_regbit_get(avr, vector->enable)) {
  76                 if (!avr->pending_wait)
  77                         avr->pending_wait = 1;          // latency on interrupts ??
  78                 if (avr->state != cpu_Running) {
  79                         if (vector->trace)
  80                                 printf("Waking CPU due to interrupt\n");
  81                         avr->state = cpu_Running;       // in case we were sleeping
  82                 }
  83         }
  84         // return 'raised' even if it was already pending
  85         return 1;
  86 }
  87
  88 void avr_clear_interrupt(avr_t * avr, int v)
  89 {
  90         avr_int_vector_t * vector = avr->vector[v];
  91         avr->pending[v >> 5] &= ~(1 << (v & 0x1f));
  92         if (!vector)
  93                 return;
  94         if (vector->trace)
  95                 printf("%s cleared %d\n", __FUNCTION__, vector->vector);
  96         avr_raise_irq(&vector->irq, 0);
  97         if (vector->raised.reg)
  98                 avr_regbit_clear(avr, vector->raised);
  99 }
 100
 101 int avr_clear_interupt_if(avr_t * avr, avr_int_vector_t * vector, uint8_t old)
 102 {
 103         if (avr_regbit_get(avr, vector->raised)) {
 104                 avr_clear_interrupt(avr, vector->vector);
 105                 avr_regbit_clear(avr, vector->raised);
 106                 return 1;
 107         }
 108         avr_regbit_setto(avr, vector->raised, old);
 109         return 0;
 110 }
 111
 112 avr_irq_t * avr_get_interupt_irq(avr_t * avr, uint8_t v)
 113 {
 114         avr_int_vector_t * vector = avr->vector[v];
 115         return vector ? &vector->irq : NULL;
 116 }
 117
 118 /*
 119  * check whether interrupts are pending. If so, check if the interrupt "latency" is reached,
 120  * and if so triggers the handlers and jump to the vector.
 121  */
 122 void avr_service_interrupts(avr_t * avr)
 123 {
 124         if (!avr->sreg[S_I])
 125                 return;
 126
 127         if (avr_has_pending_interrupts(avr)) {
 128                 if (avr->pending_wait) {
 129                         avr->pending_wait--;
 130                         if (avr->pending_wait == 0) {
 131                                 int done = 0;
 132                                 for (int bi = 0; bi < 2 && !done; bi++)
 133                                         if (avr->pending[bi]) {
 134                                                 uint32_t map = avr->pending[bi];
 135                                                 while (map) {
 136                                                         int bit = ffs(map)-1;
 137                                                         int v = (bi * 32) + bit;        // vector
 138                                                         avr_int_vector_t * vector = avr->vector[v];
 139                                                         // if that single interupt is masked, ignore it and continue
 140                                                         if (vector && !avr_regbit_get(avr, vector->enable)) {
 141                                                                 map &= ~(1 << bit);
 142                                                                 continue;
 143                                                         }
 144                                                         if (vector && vector->trace)
 145                                                                 printf("%s calling %d\n", __FUNCTION__, v);
 146                                                         _avr_push16(avr, avr->pc >> 1);
 147                                                         avr->sreg[S_I] = 0;
 148                                                         avr->pc = v * avr->vector_size;
 149
 150                                                         avr_clear_interrupt(avr, v);
 151                                                         done = 1;
 152                                                         break;
 153                                                 }
 154                                                 break;
 155                                         }
 156                         }
 157                 } else
 158                         avr->pending_wait = 2;  // for next one...
 159         }
 160 }
 161