include/sys_clock.h: simplify _NEED_PRECISE_TICK_MS_CONVERSION

This is just hygiene. Some preprocessor logic is optimized, eliminating a temporary (_NON_OPTIMIZED_TICKS_PER_SEC) in the process. Signed-off-by: Charles E. Youse <[email protected]>
keestux · May 8, 2019 · e1cb4ca · e1cb4ca
1 parent 3667d0b
commit e1cb4ca
Showing 1 changed file with 9 additions and 16 deletions.
diff --git a/include/sys_clock.h b/include/sys_clock.h
@@ -79,27 +79,20 @@ static inline int sys_clock_hw_cycles_per_tick(void)
 
 /* kernel clocks */
 
-#ifdef CONFIG_SYS_CLOCK_EXISTS
-
 /*
- * If timer frequency is known at compile time, a simple (32-bit)
- * tick <-> ms conversion could be used for some combinations of
- * hardware timer frequency and tick rate. Otherwise precise
- * (64-bit) calculations are used.
+ * We default to using 64-bit intermediates in timescale conversions,
+ * but if the HW timer cycles/sec, ticks/sec and ms/sec are all known
+ * to be nicely related, then we can cheat with 32 bits instead.
  */
 
-#if !defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME)
-#if (CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) != 0
-	#define _NEED_PRECISE_TICK_MS_CONVERSION
-#elif (MSEC_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) != 0
-	#define _NON_OPTIMIZED_TICKS_PER_SEC
-#endif
-#endif
+#ifdef CONFIG_SYS_CLOCK_EXISTS
 
-#if	defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) || \
-	defined(_NON_OPTIMIZED_TICKS_PER_SEC)
-	#define _NEED_PRECISE_TICK_MS_CONVERSION
+#if defined(CONFIG_TIMER_READS_ITS_FREQUENCY_AT_RUNTIME) || \
+	(MSEC_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC) || \
+	(CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC % CONFIG_SYS_CLOCK_TICKS_PER_SEC)
+#define _NEED_PRECISE_TICK_MS_CONVERSION
 #endif
+
 #endif
 
 static ALWAYS_INLINE s32_t z_ms_to_ticks(s32_t ms)