diff options
Diffstat (limited to 'wirish/time.c')
| -rw-r--r-- | wirish/time.c | 54 |
1 files changed, 15 insertions, 39 deletions
diff --git a/wirish/time.c b/wirish/time.c index 69e962c..ea8ebe1 100644 --- a/wirish/time.c +++ b/wirish/time.c @@ -23,8 +23,6 @@ * ****************************************************************************/ /** - * @file time.c - * * @brief */ @@ -32,46 +30,24 @@ #include "systick.h" #include "time.h" -#define CYCLES_PER_MICROSECOND 72 -#define FUDGE 42 - -extern volatile uint32 systick_timer_millis; - -uint32 millis() { - unsigned long m; - m = systick_timer_millis; - return m; -} - void delay(unsigned long ms) { - unsigned long start = millis(); - - while (millis() - start <= ms) - ; + uint32 i; + for (i = 0; i < ms; i++) { + delayMicroseconds(1000); + } } - - -#if 1 void delayMicroseconds(uint32 us) { - uint32 target; - uint32 last, cur, count; - /* fudge factor hacky hack hack for function overhead */ - target = us * CYCLES_PER_MICROSECOND - FUDGE; - - /* Get current count */ - last = systick_get_count(); - cur = systick_get_count(); - count = last; - while ((count-cur) <= target) { - cur = systick_get_count(); - - /* check for overflow */ - if (cur > last) { - count += MAPLE_RELOAD_VAL; - } - last = cur; - } + // So (2^32)/12 micros max, or less than 6 minutes + us *= 12; + + /* fudge for function call overhead */ + us--; + asm volatile(" mov r0, %[us] \n\t" + "1: subs r0, #1 \n\t" + " bhi 1b \n\t" + : + : [us] "r" (us) + : "r0"); } -#endif |