stmhal: Use MP_OBJ_NEW_SMALL_INT directly in pyb.micros/millis.

dpgeorge · dpgeorge · commit 29c92a407c8f · 2014-08-25T17:38:55.000+01:00
Also some whitespace cleanup.
diff --git a/stmhal/modpyb.c b/stmhal/modpyb.c
@@ -198,11 +198,10 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_sync_obj, pyb_sync);
 /// always get the right answer and not have to worry about whether pyb.millis()
 /// wraps around.
 STATIC mp_obj_t pyb_millis(void) {
-    // We want to "cast" the 32 bit unsigned into a small-int. So we shift it
-    // left by 1 to throw away the top bit, and then shift it right by one
-    // to sign extend.
-    mp_int_t val = HAL_GetTick() << 1;
-    return mp_obj_new_int(val >> 1);
+    // We want to "cast" the 32 bit unsigned into a small-int.  This means
+    // copying the MSB down 1 bit (extending the sign down), which is
+    // equivalent to just using the MP_OBJ_NEW_SMALL_INT macro.
+    return MP_OBJ_NEW_SMALL_INT(HAL_GetTick());
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_millis_obj, pyb_millis);
 
@@ -219,11 +218,10 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_millis_obj, pyb_millis);
 /// always get the right answer and not have to worry about whether pyb.micros()
 /// wraps around.
 STATIC mp_obj_t pyb_micros(void) {
-    // We want to "cast" the 32 bit unsigned into a small-int. So we shift it
-    // left by 1 to throw away the top bit, and then shift it right by one
-    // to sign extend.
-    mp_int_t val = sys_tick_get_microseconds() << 1;
-    return mp_obj_new_int(val >> 1);
+    // We want to "cast" the 32 bit unsigned into a small-int.  This means
+    // copying the MSB down 1 bit (extending the sign down), which is
+    // equivalent to just using the MP_OBJ_NEW_SMALL_INT macro.
+    return MP_OBJ_NEW_SMALL_INT(sys_tick_get_microseconds());
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(pyb_micros_obj, pyb_micros);
 
diff --git a/stmhal/systick.c b/stmhal/systick.c
@@ -51,29 +51,29 @@ void sys_tick_wait_at_least(uint32_t start_tick, uint32_t delay_ms) {
 //
 // We assume that HAL_GetTickis returns milliseconds.
 uint32_t sys_tick_get_microseconds(void) {
-    mp_int_t enabled = disable_irq();
+    mp_uint_t irq_state = disable_irq();
     uint32_t counter = SysTick->VAL;
     uint32_t milliseconds = HAL_GetTick();
     uint32_t status  = SysTick->CTRL;
-    enable_irq(enabled);
+    enable_irq(irq_state);
 
-  // It's still possible for the countflag bit to get set if the counter was
-  // reloaded between reading VAL and reading CTRL. With interrupts  disabled
-  // it definitely takes less than 50 HCLK cycles between reading VAL and
-  // reading CTRL, so the test (counter > 50) is to cover the case where VAL
-  // is +ve and very close to zero, and the COUNTFLAG bit is also set.
-  if ((status & SysTick_CTRL_COUNTFLAG_Msk) && counter > 50) {
-    // This means that the HW reloaded VAL between the time we read VAL and the
-    // time we read CTRL, which implies that there is an interrupt pending
-    // to increment the tick counter.
-    milliseconds++;
-  }
-  uint32_t load = SysTick->LOAD;
-  counter = load - counter; // Convert from decrementing to incrementing
+    // It's still possible for the countflag bit to get set if the counter was
+    // reloaded between reading VAL and reading CTRL. With interrupts  disabled
+    // it definitely takes less than 50 HCLK cycles between reading VAL and
+    // reading CTRL, so the test (counter > 50) is to cover the case where VAL
+    // is +ve and very close to zero, and the COUNTFLAG bit is also set.
+    if ((status & SysTick_CTRL_COUNTFLAG_Msk) && counter > 50) {
+        // This means that the HW reloaded VAL between the time we read VAL and the
+        // time we read CTRL, which implies that there is an interrupt pending
+        // to increment the tick counter.
+        milliseconds++;
+    }
+    uint32_t load = SysTick->LOAD;
+    counter = load - counter; // Convert from decrementing to incrementing
 
-  // ((load + 1) / 1000) is the number of counts per microsecond.
-  //
-  // counter / ((load + 1) / 1000) scales from the systick clock to microseconds
-  // and is the same thing as (counter * 1000) / (load + 1)
-  return milliseconds * 1000 + (counter * 1000) / (load + 1);
+    // ((load + 1) / 1000) is the number of counts per microsecond.
+    //
+    // counter / ((load + 1) / 1000) scales from the systick clock to microseconds
+    // and is the same thing as (counter * 1000) / (load + 1)
+    return milliseconds * 1000 + (counter * 1000) / (load + 1);
 }
diff --git a/teensy/teensy_hal.h b/teensy/teensy_hal.h
@@ -5,7 +5,7 @@
   void assert_failed(uint8_t* file, uint32_t line);
 #else
   #define assert_param(expr) ((void)0)
-#endif /* USE_FULL_ASSERT */    
+#endif /* USE_FULL_ASSERT */
 
 #define FTM0    ((FTM_TypeDef *)&FTM0_SC)
 #define FTM1    ((FTM_TypeDef *)&FTM1_SC)
@@ -113,25 +113,20 @@ typedef struct {
 #define GPIO_AF6_I2C1   6
 #define GPIO_AF7_FTM1   7
 
-
-__attribute__(( always_inline )) static inline void __WFI(void)
-{
+__attribute__(( always_inline )) static inline void __WFI(void) {
   __asm volatile ("wfi");
 }
 
-__attribute__(( always_inline )) static inline uint32_t __get_PRIMASK(void)
-{
+__attribute__(( always_inline )) static inline uint32_t __get_PRIMASK(void) {
     uint32_t result;
     __asm volatile ("MRS %0, primask" : "=r" (result));
     return(result);
 }
 
-__attribute__(( always_inline )) static inline void __set_PRIMASK(uint32_t priMask)
-{
+__attribute__(( always_inline )) static inline void __set_PRIMASK(uint32_t priMask) {
     __asm volatile ("MSR primask, %0" : : "r" (priMask) : "memory");
 }
 
-
 uint32_t HAL_GetTick(void);
 void     HAL_Delay(uint32_t Delay);
 
