10 #define TIMER_QUANTUM 100
11 // 2^(15-rate), 14: 2Hz, 5: 1024Hz, 2: 8192Hz
12 // (Max: 14, Min: 2) - 14 = 2Hz, 13 = 4Hz, 12 = 8Hz, 11 = 16Hz 10 = 32Hz, 2 = 8192Hz
13 //#define TIMER_RATE 10 // 32 Hz
14 //#define TIMER_RATE 12 // 8 Hz
15 #define TIMER_RATE 14 // 2 Hz - Lowest
16 #define TIMER_FREQ (0x8000>>TIMER_RATE) //Hz
17 #define MS_PER_TICK_WHOLE (1000/(TIMER_FREQ))
18 #define MS_PER_TICK_FRACT ((0x80000000*(1000%TIMER_FREQ))/TIMER_FREQ)
19 #define US_PER_TICK (1000*1000/(TIMER_FREQ))
22 extern volatile Sint64 giTimestamp;
23 extern volatile Uint64 giTicks;
24 extern volatile Uint64 giPartMiliseconds;
25 extern void Timer_CallTimers(void);
28 volatile Uint64 giTime_TSCAtLastTick = 0;
29 volatile Uint64 giTime_TSCPerTick = 0;
34 void Time_Interrupt(int IRQ, void *Ptr);
35 Uint64 Time_ReadTSC(void);
40 * \brief Return the current timestamp
44 Uint64 tsc = Time_ReadTSC();
45 tsc -= giTime_TSCAtLastTick;
46 tsc *= MS_PER_TICK_WHOLE;
47 if( giTime_TSCPerTick ) {
48 tsc /= giTime_TSCPerTick;
52 return giTimestamp + tsc;
56 * \fn int Time_Setup(void)
57 * \brief Sets the system time from the Realtime-Clock
63 Log_Log("Timer", "RTC Timer firing at %iHz (%i divisor), %i.0x%08x",
64 TIMER_FREQ, TIMER_RATE, MS_PER_TICK_WHOLE, MS_PER_TICK_FRACT);
66 outb(0x70, inb(0x70)&0x7F); // Disable NMIs
67 __asm__ __volatile__ ("cli"); // Disable normal interrupts
69 // Set IRQ8 firing rate
70 outb(0x70, 0x0A); // Set the index to register A
71 val = inb(0x71); // Get the current value of register A
74 outb(0x70, 0x0A); // Reset index to A
75 outb(0x71, val); // Update the timer rate
78 outb(0x70, 0x0B); // Set the index to register B
79 val = inb(0x71); // Read the current value of register B
80 outb(0x70, 0x0B); // Set the index again (a read will reset the index to register D)
81 outb(0x71, val | 0x40); // Write the previous value or'd with 0x40. This turns on bit 6 of register D
83 __asm__ __volatile__ ("sti"); // Re-enable normal interrupts
84 outb(0x70, inb(0x70)|0x80); // Re-enable NMIs
86 // Install IRQ Handler
87 IRQ_AddHandler(8, Time_Interrupt, NULL);
89 // Make sure the RTC actually fires
90 outb(0x70, 0x0C); // Select register C
91 inb(0x71); // Just throw away contents.
97 * \brief Called on the timekeeping IRQ
99 void Time_Interrupt(int IRQ, void *Ptr)
101 Uint64 curTSC = Time_ReadTSC();
103 if( giTime_TSCAtLastTick )
105 giTime_TSCPerTick = curTSC - giTime_TSCAtLastTick;
107 giTime_TSCAtLastTick = curTSC;
110 giTimestamp += MS_PER_TICK_WHOLE;
111 giPartMiliseconds += MS_PER_TICK_FRACT;
112 if(giPartMiliseconds > 0x80000000) {
114 giPartMiliseconds -= 0x80000000;
119 // Make sure the RTC Fires again
120 outb(0x70, 0x0C); // Select register C
121 inb(0x71); // Just throw away contents.
124 void Time_MicroSleep(Uint16 Microsecs) // max 64 ms
126 Uint64 cur_tsc = Time_ReadTSC();
127 // tsc_per_us * Microsec
128 Uint64 delta_tsc = (Uint64)Microsecs * giTime_TSCPerTick / US_PER_TICK;
129 Uint64 tgt_tsc = cur_tsc + delta_tsc;
131 if( tgt_tsc < cur_tsc )
132 while(Time_ReadTSC() > cur_tsc)
135 while( Time_ReadTSC() < tgt_tsc )
139 Uint64 Time_ReadTSC(void)
142 __asm__ __volatile__ ("rdtsc" : "=a" (a), "=d" (d));
143 return ((Uint64)d << 32) | a;