Rework avr_service_interrupts() to use ffs() too for speed.

diff --git a/simavr/sim/sim_interrupts.c b/simavr/sim/sim_interrupts.c
index 9bbda0d..4702e56 100644 (file)
--- a/simavr/sim/sim_interrupts.c
+++ b/simavr/sim/sim_interrupts.c
@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
+#include <strings.h>
 #include "sim_interrupts.h"
 #include "sim_core.h"
 
@@ -128,15 +129,18 @@ void avr_service_interrupts(avr_t * avr)
                        avr->pending_wait--;
                        if (avr->pending_wait == 0) {
                                int done = 0;
-                               for (int bi = 0; bi < 2 && !done; bi++) if (avr->pending[bi]) {
-                                       for (int ii = 0; ii < 32 && !done; ii++)
-                                               if (avr->pending[bi] & (1 << ii)) {
-
-                                                       int v = (bi * 32) + ii; // vector
+                               for (int bi = 0; bi < 2 && !done; bi++)
+                                       if (avr->pending[bi]) {
+                                               uint32_t map = avr->pending[bi];
+                                               while (map) {
+                                                       int bit = ffs(map)-1;
+                                                       int v = (bi * 32) + bit;        // vector
                                                        avr_int_vector_t * vector = avr->vector[v];
                                                        // if that single interupt is masked, ignore it and continue
-                                                       if (vector && !avr_regbit_get(avr, vector->enable))
+                                                       if (vector && !avr_regbit_get(avr, vector->enable)) {
+                                                               map &= ~(1 << bit);
                                                                continue;
+                                                       }
                                                        if (vector && vector->trace)
                                                                printf("%s calling %d\n", __FUNCTION__, v);
                                                        _avr_push16(avr, avr->pc >> 1);
@@ -147,8 +151,8 @@ void avr_service_interrupts(avr_t * avr)
                                                        done = 1;
                                                        break;
                                                }
-                                       break;
-                               }
+                                               break;
+                                       }
                        }
                } else
                        avr->pending_wait = 2;  // for next one...