1 files changed, 67 insertions, 0 deletions
diff --git a/platforms/timer.h b/platforms/timer.h
new file mode 100644
index 0000000000..02e39e79e7
--- /dev/null
+++ b/platforms/timer.h
@@ -0,0 +1,67 @@
+/*
+Copyright 2011 Jun Wako <wakojun@gmail.com>
+Copyright 2021 Simon Arlott
+
+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
+the Free Software Foundation, either version 2 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#if __has_include_next("_timer.h")
+#    include_next "_timer.h" /* Include the platform's _timer.h */
+#endif
+
+#include <stdint.h>
+
+#define TIMER_DIFF(a, b, max) ((max == UINT8_MAX) ? ((uint8_t)((a) - (b))) : ((max == UINT16_MAX) ? ((uint16_t)((a) - (b))) : ((max == UINT32_MAX) ? ((uint32_t)((a) - (b))) : ((a) >= (b) ? (a) - (b) : (max) + 1 - (b) + (a)))))
+#define TIMER_DIFF_8(a, b) TIMER_DIFF(a, b, UINT8_MAX)
+#define TIMER_DIFF_16(a, b) TIMER_DIFF(a, b, UINT16_MAX)
+#define TIMER_DIFF_32(a, b) TIMER_DIFF(a, b, UINT32_MAX)
+#define TIMER_DIFF_RAW(a, b) TIMER_DIFF_8(a, b)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+extern volatile uint32_t timer_count;
+
+void     timer_init(void);
+void     timer_clear(void);
+uint16_t timer_read(void);
+uint32_t timer_read32(void);
+uint16_t timer_elapsed(uint16_t last);
+uint32_t timer_elapsed32(uint32_t last);
+
+// Utility functions to check if a future time has expired & autmatically handle time wrapping if checked / reset frequently (half of max value)
+#define timer_expired(current, future) ((uint16_t)(current - future) < UINT16_MAX / 2)
+#define timer_expired32(current, future) ((uint32_t)(current - future) < UINT32_MAX / 2)
+
+// Use an appropriate timer integer size based on architecture (16-bit will overflow sooner)
+#if FAST_TIMER_T_SIZE < 32
+#    define TIMER_DIFF_FAST(a, b) TIMER_DIFF_16(a, b)
+#    define timer_expired_fast(current, future) timer_expired(current, future)
+typedef uint16_t fast_timer_t;
+fast_timer_t inline timer_read_fast(void) { return timer_read(); }
+fast_timer_t inline timer_elapsed_fast(fast_timer_t last) { return timer_elapsed(last); }
+#else
+#    define TIMER_DIFF_FAST(a, b) TIMER_DIFF_32(a, b)
+#    define timer_expired_fast(current, future) timer_expired32(current, future)
+typedef uint32_t fast_timer_t;
+fast_timer_t inline timer_read_fast(void) { return timer_read32(); }
+fast_timer_t inline timer_elapsed_fast(fast_timer_t last) { return timer_elapsed32(last); }
+#endif
+
+#ifdef __cplusplus
+}
+#endif