backported fixes from 256boss

[bootcensus] / src / timer.c

diff --git a/src/timer.c b/src/timer.c
index 8578c94..77c4bbe 100644 (file)
--- a/src/timer.c
+++ b/src/timer.c
@@ -1,6 +1,6 @@
 /*
-pcboot - bootable PC demo/game kernel
-Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+256boss - bootable launcher for 256b intros
+Copyright (C) 2018-2019  John Tsiombikas <nuclear@member.fsf.org>
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -19,6 +19,7 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "intr.h"
 #include "asmops.h"
 #include "timer.h"
+#include "panic.h"
 #include "config.h"
 
 /* frequency of the oscillator driving the 8254 timer */
@@ -57,11 +58,11 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 struct timer_event {
        int dt; /* remaining ticks delta from the previous event */
+       void (*func)(void);
        struct timer_event *next;
 };
 
-/* defined in intr_asm.S */
-void intr_entry_fast_timer(void);
+static void timer_handler(int inum);
 
 static struct timer_event *evlist;
 
@@ -83,14 +84,99 @@ void init_timer(void)
        outb((reload_count >> 8) & 0xff, PORT_DATA0);
 
        /* set the timer interrupt handler */
-       /*interrupt(IRQ_TO_INTR(0), timer_handler);*/
-       /* set low level fast timer interrupt routine directly in the IDT */
-       set_intr_entry(IRQ_TO_INTR(0), intr_entry_fast_timer);
+       interrupt(IRQ_TO_INTR(0), timer_handler);
+}
+
+void set_alarm(unsigned long msec, void (*func)(void))
+{
+       int ticks, tsum, iflag;
+       struct timer_event *ev, *node;
+
+       if((ticks = MSEC_TO_TICKS(msec)) <= 0) {
+               return;
+       }
+
+       if(!(ev = malloc(sizeof *ev))) {
+               panic("failed to allocate timer event");
+               return;
+       }
+       ev->func = func;
+
+       iflag = get_intr_flag();
+       disable_intr();
+
+       if(!evlist || ticks < evlist->dt) {
+               /* insert at the begining */
+               ev->next = evlist;
+               evlist = ev;
+
+               ev->dt = ticks;
+               if(ev->next) {
+                       ev->next->dt -= ticks;
+               }
+       } else {
+               tsum = evlist->dt;
+               node = evlist;
+
+               while(node->next && ticks > tsum + node->next->dt) {
+                       tsum += node->next->dt;
+                       node = node->next;
+               }
+
+               ev->next = node->next;
+               node->next = ev;
+
+               /* fix the relative times */
+               ev->dt = ticks - tsum;
+               if(ev->next) {
+                       ev->next->dt -= ev->dt;
+               }
+       }
+
+       set_intr_flag(iflag);
+}
+
+void cancel_alarm(void (*func)(void))
+{
+       int iflag;
+       struct timer_event *ev, *node;
+       struct timer_event dummy;
+
+       iflag = get_intr_flag();
+       disable_intr();
+
+       dummy.next = evlist;
+       node = &dummy;
+       while(node->next) {
+               ev = node->next;
+               if(ev->func == func) {
+                       /* found it */
+                       if(ev->next) {
+                               ev->next->dt += ev->dt;
+                       }
+                       node->next = ev->next;
+                       free(ev);
+                       break;
+               }
+               node = node->next;
+       }
+
+       set_intr_flag(iflag);
 }
 
-/*
 static void timer_handler(int inum)
 {
        nticks++;
+
+       if(evlist) {
+               evlist->dt--;
+
+               while(evlist && evlist->dt <= 0) {
+                       struct timer_event *ev = evlist;
+                       evlist = evlist->next;
+
+                       ev->func();
+                       free(ev);
+               }
+       }
 }
-*/