Add README

[rgblamp.git] / tmr.c

diff --git a/tmr.c b/tmr.c
index aa3f58df722b644e007b1dc98118991827af5354..ad30e9c3a99339ecee522de8f46cc8dc82f95a12 100644 (file)
--- a/tmr.c
+++ b/tmr.c
@@ -1,3 +1,32 @@
+/*
+ * Copyright © 2011, 2012, Titanium Mirror, Inc..
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * - Redistributions of source code must retain the above copyright notice,
+ *   this list of conditions and the following disclaimer.
+ * - Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ * - Neither the name of Titanium Mirror, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived from
+ *   this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
+ * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
 /*
  * File:   tmr.c
  *
@@ -15,7 +44,7 @@
 persistent tmr_time_t _tmr_ticks;
 tmr_bitno_t _tmr_on;
 tmr_bitno_t _tmr_periodic;
-static tmr_bitno_t _tmr_fired;
+static tmr_bitno_t _tmr_flag;
 static tmr_time_t _tmr_t0[TMR_COUNT];
 static tmr_time_t _tmr_elapsed[TMR_COUNT];
 
@@ -37,7 +66,7 @@ static tmr_time_t _tmr_elapsed[TMR_COUNT];
 
 void tmr_init()
 {
-  /* Configure Timer0 to overflow every 32 msec.  Adjust with
+  /* Configure Timer0 to overflow every 32 msec.  Adjust for
    * Fosc as set in picinit.[ch].  At 4 MHz, prescale is 1:128.
    * TMR0CS = 0, PSA = 0, PS = 0b110
   */
@@ -52,7 +81,7 @@ void tmr_start(tmr_bitno_t t, tmr_time_t elapsed)
   ndi();
   bit_set(_tmr_on, t);
   bit_clr(_tmr_periodic, t);
-  bit_clr(_tmr_fired, t);
+  bit_clr(_tmr_flag, t);
   _tmr_t0[t] = _tmr_ticks;
   _tmr_elapsed[t] = elapsed;
   nei();
@@ -63,8 +92,8 @@ void tmr_startAt(tmr_bitno_t t, tmr_time_t t0, tmr_time_t elapsed)
   ndi();
   bit_set(_tmr_on, t);
   bit_clr(_tmr_periodic, t);
-  bit_clr(_tmr_fired, t);
-  _tmr_t0[t] = t0 + elapsed;
+  bit_clr(_tmr_flag, t);
+  _tmr_t0[t] = t0;
   nei();
 }
 
@@ -73,8 +102,8 @@ void tmr_startPeriodic(tmr_bitno_t t, tmr_time_t elapsed)
   ndi();
   bit_set(_tmr_on, t);
   bit_set(_tmr_periodic, t);
-  bit_clr(_tmr_fired, t);
-  _tmr_t0[t] = _tmr_ticks + elapsed;
+  bit_clr(_tmr_flag, t);
+  _tmr_t0[t] = _tmr_ticks;
   _tmr_elapsed[t] = elapsed;
   nei();
 }
@@ -84,24 +113,22 @@ void tmr_startPeriodicAt(tmr_bitno_t t, tmr_time_t t0, tmr_time_t elapsed)
   ndi();
   bit_set(_tmr_on, t);
   bit_set(_tmr_periodic, t);
-  bit_clr(_tmr_fired, t);
-  _tmr_t0[t] = t0 + elapsed;
+  bit_clr(_tmr_flag, t);
+  _tmr_t0[t] = t0;
   _tmr_elapsed[t] = elapsed;
   nei();
 }
 
 bit tmr_fired(tmr_bitno_t t)
 {
-  /* FIXME: if called from ISR ndi()/nei() is not required */
-  static unsigned char last_fired;
   unsigned char fired;
 
   ndi();
-  fired = bit_get(_tmr_fired, t) != 0;
+  fired = bit_get(_tmr_flag, t);
   if (fired)
-    bit_clr(_tmr_fired, t);
+    bit_clr(_tmr_flag, t);
   nei();
-  return fired;
+  return fired != 0;
 }
 
 void tmr_isr()
@@ -110,8 +137,9 @@ void tmr_isr()
     TMR0IF = 0;
     _tmr_ticks++;
     for (tmr_bitno_t t = 0; t < TMR_COUNT; t++) {
-      if (_tmr_ticks - _tmr_t0[t] <= 0) {
-        bit_set(_tmr_fired, t);
+      if (bit_get(_tmr_on, t) &&
+          (tmr_time_t)(_tmr_ticks - _tmr_t0[t]) >= _tmr_elapsed[t]) {
+        bit_set(_tmr_flag, t);
         if (bit_get(_tmr_periodic, t))
           _tmr_t0[t] += _tmr_elapsed[t];
         else
@@ -121,17 +149,8 @@ void tmr_isr()
   }
 }
 
-/* Wait for a specific timer value t */
-#define tmr_wait(t) while (TMR0 != t);
-
 void tmr_uwait(unsigned us)
 {
-  unsigned t0 = TMR0;
-
-  while (us >= 32768) {
-    tmr_wait(t0);
-    us -= 32768;
-  }
   while (us >= 16384) {
     tmr_cwait(128);
     us -= 16384;
@@ -141,12 +160,6 @@ void tmr_uwait(unsigned us)
 
 void tmr_mwait(unsigned ms)
 {
-  unsigned t0 = TMR0;
-
-  while (ms >= 32) {
-    tmr_wait(t0);
-    ms -= 32;
-  }
   while (ms >= 16) {
     tmr_cwait(128);
     ms -= 16;