Kernel/x86 - Untested MicroSleep function

diff --git a/KernelLand/Kernel/arch/x86/time.c b/KernelLand/Kernel/arch/x86/time.c
index 9b59b30..c79d459 100644 (file)
--- a/KernelLand/Kernel/arch/x86/time.c
+++ b/KernelLand/Kernel/arch/x86/time.c
@@ -15,6 +15,7 @@
 #define TIMER_FREQ     (0x8000>>TIMER_RATE)    //Hz
 #define MS_PER_TICK_WHOLE      (1000/(TIMER_FREQ))
 #define MS_PER_TICK_FRACT      ((0x80000000*(1000%TIMER_FREQ))/TIMER_FREQ)
+#define US_PER_TICK    (1000*1000/(TIMER_FREQ))
 
 // === IMPORTS ===
 extern volatile Sint64 giTimestamp;
@@ -119,6 +120,21 @@ void Time_Interrupt(int IRQ, void *Ptr)
        inb(0x71);      // Just throw away contents.
 }
 
+void Time_MicroSleep(Uint16 Microsecs) // max 64 ms
+{
+       Uint64  cur_tsc = Time_ReadTSC();
+       // tsc_per_us * Microsec
+       Uint64  delta_tsc = (Uint64)Microsecs * giTime_TSCPerTick / US_PER_TICK;
+       Uint64  tgt_tsc = cur_tsc + delta_tsc;
+
+       if( tgt_tsc < cur_tsc )
+               while(Time_ReadTSC() > cur_tsc)
+                       ;       
+
+       while( Time_ReadTSC() < tgt_tsc )
+               ;
+}
+
 Uint64 Time_ReadTSC(void)
 {
        Uint32  a, d;