Reimplemented PIT Timer. Sleep is now a syscall. Also made docs/ that contains some info so i don't forget.

include/pit.h

@@ -0,0 +1,47 @@
+#ifndef TIMER_H
+#define TIMER_H
+
+#include <stdint.h>
+#include <idt.h>
+#include <pic.h>
+#include <screen.h>
+
+#define CHANNEL_0 0x40 // Offset it by 1 or 2 for ch1 and ch2
+#define COMMAND   0x43
+#define INPUT_CLK 1193182
+
+static uint32_t* timerTicks = (uint32_t*)0x1000;
+
+__attribute__ ((interrupt))
+void timerHandler(intFrame_t* iframe) {
+    *timerTicks += 1;
+
+    // TODO: Improve the cursor rendering
+    if (*timerTicks % 500 == 0) putcAt(' ', cursor.x, cursor.y);
+    else if (*timerTicks % 250 == 0) putcAt(127, cursor.x, cursor.y);
+
+    sendPicEOI(0);
+}
+
+void setPitPhase(uint8_t channel, uint8_t opMode, uint16_t hz) {
+    if (channel > 2 || opMode > 7) { return; }
+    __asm__ volatile ("cli");
+
+    // Send command - bits 7-6 channel, 5-4 Access mode, 3-1 operating mode, 0 - Should be zero in x86
+    outb(COMMAND, ((channel << 6) | (3 << 4) | (opMode << 1)));
+
+    // Send frequency
+    uint16_t freq = INPUT_CLK / hz; // I solved an equation to figure this out
+    outb(CHANNEL_0 + channel, (uint8_t)freq);
+    outb(CHANNEL_0 + channel, (uint8_t)(freq >> 8));
+    
+    __asm__ volatile ("sti");
+}
+
+void setupTimer() { // Sets up IRQ 0 - PIT
+    idtSetGate(0x20, timerHandler, INT_GATE_FLAGS);
+    unsetIrqMask(0);
+    setPitPhase(0, 2, 1000); // Default setup: 1000Hz - 1 tick per 1ms
+}
+
+#endif

include/syscall.h

@@ -1,27 +1,25 @@
 #ifndef SYSCALL_H
 #define SYSCALL_H
 
-#include <screen.h>
+#include <pit.h>
 
 // System call count
 #define MAX_SYSCALLS 2
 
-void sys_test0() {
-    fgColor = YELLOW;
-    print("Syscall 0 - Test\n");
-    fgColor = FG_COLOR;
-}
+// Args: ebx - number of miliseconds
+void sys_sleep() {
+    uint32_t ms;
+    __asm__ volatile ("movl %%ebx, %0" : "=r"(ms));
 
-void sys_test1() {
-    fgColor = CYAN;
-    print("Syscall 1 - Test\n");
-    fgColor = FG_COLOR;
+    uint32_t requiredTicks = *timerTicks + ms;
+    while (*timerTicks != requiredTicks) { // Wait...
+        __asm__ volatile ("sti;hlt;cli;");
+    }
 }
 
 // System call table
 void* syscalls[MAX_SYSCALLS] = {
-    sys_test0, 
-    sys_test1, 
+    sys_sleep, 
 };
 
 // int 0x80 - Syscall interrupt, handled by this function

include/time.h

@@ -0,0 +1,8 @@
+#ifndef TIME_H
+#define TIME_H
+
+void sleep(uint32_t ms) {
+    __asm__ volatile ("int $0x80" : : "a"(0), "b"(ms));
+}
+
+#endif

include/timer.h

@@ -4,43 +4,44 @@
 #include <stdint.h>
 #include <idt.h>
 #include <pic.h>
-#include <system.h>
 #include <screen.h>
 
-#define INPUT_CLK 1193180
+#define CHANNEL_0 0x40 // Offset it by 1 or 2 for ch1 and ch2
+#define COMMAND   0x43
+#define INPUT_CLK 1193182
 
-uint32_t timerTicks = 0;
+static uint32_t* timerTicks = (uint32_t*)0x1000;
 
 __attribute__ ((interrupt))
 void timerHandler(intFrame_t* iframe) {
-    timerTicks++;
+    *timerTicks += 1;
 
     // TODO: Improve the cursor rendering
-    if (timerTicks % 500 == 0) putcAt(127, cursor.x, cursor.y);
-    else if (timerTicks % 250 == 0) putcAt(' ', cursor.x, cursor.y);
+    if (*timerTicks % 500 == 0) putcAt(' ', cursor.x, cursor.y);
+    else if (*timerTicks % 250 == 0) putcAt(127, cursor.x, cursor.y);
 
     sendPicEOI(0);
 }
 
-void setupTimer() {
-    idtSetGate(32, timerHandler, INT_GATE_FLAGS);
-    unsetIrqMask(0);
-}
+void setPitPhase(uint8_t channel, uint8_t opMode, uint16_t hz) {
+    if (channel > 2 || opMode > 7) { return; }
+    __asm__ volatile ("cli");
 
-// Source: https://en.wikibooks.org/wiki/X86_Assembly/Programmable_Interval_Timer
-void timerPhase(uint32_t hz) {
-    uint16_t div = INPUT_CLK / hz;
+    // Send command - bits 7-6 channel, 5-4 Access mode, 3-1 operating mode, 0 - Should be zero in x86
+    outb(COMMAND, ((channel << 6) | (3 << 4) | (opMode << 1)));
 
-    outb(0x43, 0x36); // Tell PIT that we're setting channel 0
-    outb(0x40, div & 0xff); // Low byte
-    outb(0x40, div >> 8); // High byte
-}
-
-void sleep(uint32_t ticks) {
-    uint32_t eticks = ticks + timerTicks;
+    // Send frequency
+    uint16_t freq = INPUT_CLK / hz; // I solved an equation to figure this out
+    outb(CHANNEL_0 + channel, (uint8_t)freq);
+    outb(CHANNEL_0 + channel, (uint8_t)(freq >> 8));
     
-    while (timerTicks != eticks); // Should ignore overflows unlike '<'
+    __asm__ volatile ("sti");
 }
 
+void setupTimer() { // Sets up IRQ 0 - PIT
+    idtSetGate(0x20, timerHandler, INT_GATE_FLAGS);
+    unsetIrqMask(0);
+    setPitPhase(0, 2, 1000); // Default setup: 1000Hz - 1 tick per 1ms
+}
 
 #endif