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

Makefile

@@ -3,7 +3,7 @@ CC = i386-elf-gcc
 LD = i386-elf-ld
 AS = nasm
 
-CFLAGS = -ffreestanding -fno-builtin -fno-stack-protector -nostdinc -mgeneral-regs-only -m32 -march=i386 -Iinclude -Wall 
+CFLAGS = -ffreestanding -fno-builtin -fno-stack-protector -nostdinc -mgeneral-regs-only -m32 -march=i386 -Iinclude -Wall
 
 SRC = ./src
 BUILD = ./build

docs/syscalls.txt

@@ -0,0 +1,11 @@
+=== System Calls === 
+
+Syscall handlers are prefixed by 'sys_'
+Syscalls can be called using interrupt 0x80
+The EAX register should countain a syscall number
+
+Here's a list of syscalls: (and their numbers)
+
+syscall(0) : Sleep()
+    Args: EBX - Number of miliseconds to sleep for
+

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() {
+// Args: ebx - number of miliseconds
-    fgColor = YELLOW;
+void sys_sleep() {
-    print("Syscall 0 - Test\n");
+    uint32_t ms;
-    fgColor = FG_COLOR;
+    __asm__ volatile ("movl %%ebx, %0" : "=r"(ms));
-}
 
-void sys_test1() {
+    uint32_t requiredTicks = *timerTicks + ms;
-    fgColor = CYAN;
+    while (*timerTicks != requiredTicks) { // Wait...
-    print("Syscall 1 - Test\n");
+        __asm__ volatile ("sti;hlt;cli;");
-    fgColor = FG_COLOR;
+    }
 }
 
 // System call table
 void* syscalls[MAX_SYSCALLS] = {
-    sys_test0, 
+    sys_sleep, 
-    sys_test1, 
 };
 
 // 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);
+    if (*timerTicks % 500 == 0) putcAt(' ', cursor.x, cursor.y);
-    else if (timerTicks % 250 == 0) putcAt(' ', cursor.x, cursor.y);
+    else if (*timerTicks % 250 == 0) putcAt(127, cursor.x, cursor.y);
 
     sendPicEOI(0);
 }
 
-void setupTimer() {
+void setPitPhase(uint8_t channel, uint8_t opMode, uint16_t hz) {
-    idtSetGate(32, timerHandler, INT_GATE_FLAGS);
+    if (channel > 2 || opMode > 7) { return; }
-    unsetIrqMask(0);
+    __asm__ volatile ("cli");
-}
 
-// Source: https://en.wikibooks.org/wiki/X86_Assembly/Programmable_Interval_Timer
+    // Send command - bits 7-6 channel, 5-4 Access mode, 3-1 operating mode, 0 - Should be zero in x86
-void timerPhase(uint32_t hz) {
+    outb(COMMAND, ((channel << 6) | (3 << 4) | (opMode << 1)));
-    uint16_t div = INPUT_CLK / hz;
 
-    outb(0x43, 0x36); // Tell PIT that we're setting channel 0
+    // Send frequency
-    outb(0x40, div & 0xff); // Low byte
+    uint16_t freq = INPUT_CLK / hz; // I solved an equation to figure this out
-    outb(0x40, div >> 8); // High byte
+    outb(CHANNEL_0 + channel, (uint8_t)freq);
-}
+    outb(CHANNEL_0 + channel, (uint8_t)(freq >> 8));
-
-void sleep(uint32_t ticks) {
-    uint32_t eticks = ticks + timerTicks;
     
-    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

src/fonts/term16n.asm

@@ -1526,22 +1526,22 @@ db 00h,\
    00h,\
    00h,\
    00h
-db 00h,\
+db 0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   00h,\
+   0xFF,\
-   0FEh
+   0xFF
    
 ;; End of visible ascii characters
    times 2048-($-$$) db 0

src/kernel.c

@@ -9,7 +9,8 @@
 #include <string.h>
 #include <graphics.h>
 #include <keyboard.h>
-#include <timer.h>
+#include <pit.h>
+#include <time.h>
 
 #define PROMPT "#> "
 
@@ -54,7 +55,6 @@ void main() {
     __asm__ volatile ("sti");
 
     setupTimer();
-    timerPhase(1000); // 1 kHz
     setupKeyboard();
 
     // Run Interactive Shell Program
@@ -166,7 +166,7 @@ void main() {
             drawCircle(1500, 600, 300, WHITE);
             fillCircle(950, 750, 75, rgb(0xa2, 0xd6, 0xf9));
 
-            //read('q'); // Wait until we get a 'q'
+            read('q'); // Wait until we get a 'q'
             clear();
         } else if (strcmp(input, "help") == 0) {
             print("Available Commands:\n");
@@ -179,6 +179,7 @@ void main() {
             print(" ls         | Lists all available files\n");
             print(" memmap     | Prints the memory map and info\n");
             print(" reboot     | Reboots the system\n");
+            print(" sleep      | Sleeps for input number of seconds\n");
             print(" test       | Performs tests\n");
         } else if (strcmp(input, "ls") == 0) {
             printFiletable(filetable);
@@ -186,6 +187,13 @@ void main() {
             printPhysicalMemmap();
         } else if (strcmp(input, "reboot") == 0) {
             outb(0x64, 0xFE);
+        } else if (strcmp(input, "sleep") == 0) {
+            if (*args == '\0') continue;
+
+            uint32_t ms = atoi(args) * 1000; // Convert seconds to miliseconds
+            if (ms == 0) continue;
+
+            sleep(ms);
         } else if (strcmp(input, "test") == 0) {
             print("Running Tests...\n");
             uint8_t buf[512];
@@ -206,9 +214,6 @@ void main() {
             } else {
                 print("[ FAIL ]\n");
             }
-            print("Syscall Test:\n");
-            __asm__ volatile ("movl $0, %eax; int $0x80"); // Syscall(0);
-            __asm__ volatile ("movl $1, %eax; int $0x80"); // Syscall(1);
             
             print("\nTests Finished!\n");
         } else {

todo.txt

@@ -9,10 +9,11 @@ Legend:
 
 - [x] Multistage Bootloader
 - [ ] Bootloader reads filetable to find files
+- [ ] The almighty 'printf()'
 - [!] Makefile refactorin'
 - [x] Write down where stuff is in memory (in notes.txt)
 - [ ] "Text" mode (not actually)
-    - [ ] Scrolling
+    - [x] Scrolling
     - [ ] Scroll-back
     - [ ] Color codes (and just multicolor text in general)
     - [x] VESA BIOS Extensions
@@ -34,12 +35,15 @@ Legend:
     - [x] Triangles (3D?!!???)
     - [x] Rectange :)
     - [x] Circle!
-    - [_] Filled verisons
+    - [x] Filled verisons
-- [ ] Interrupts
+- [ ] Interrupts
     - [x] IDT Setup (idt.h)
     - [x] Exception handling
-    - [ ] Hardware/software interrupts
+    - [x] Hardware/software interrupts
-    - [ ] Syscalls! (int 0x80)
+    - [x] Syscalls! (int 0x80)
+    - [ ] IRQ 0 - PIT
+    - [ ] IRQ 1 - Keyboard
+    - [ ] IRQ 8 - CMOS Real time clock
 - [ ] Math
     - [ ] Trigonometry
         - [ ] Sine
@@ -63,6 +67,7 @@ Legend:
     - [ ] NAN
     - [x] E (eulers number)
     - [x] PI
+    - [ ] Floating point macros/functions
 - [ ] Filesystem
     - [ ] Utility for filesystem building (not just an assembly file)
     - [x] Filetable
@@ -77,6 +82,7 @@ Legend:
         - [ ] Symbolic
         - [ ] Hard
 - [ ] System Calls
+    - [ ] Sleep()
     - [ ] Write()
     - [ ] Read()
     - [ ] Open()
@@ -103,7 +109,6 @@ Legend:
     - [ ] stdin
     - [ ] stdout
     - [ ] stderr
-    - [ ] printf
 - [ ] Memory manager
     - [x] Memory map
     - [x] Print mem map