Initial import of ViperOS

VKernel/Kernel/platform/pch/pit.py

@@ -0,0 +1,26 @@
+import asm
+import t, c
+
+PIT_CHANNEL0: t.CDefine = 0x40
+PIT_CHANNEL1: t.CDefine = 0x41
+PIT_CHANNEL2: t.CDefine = 0x42
+PIT_COMMAND:  t.CDefine = 0x43
+
+def pit_init(frequency: t.CInt):
+    # 参数验证：确保频率为正数
+    if frequency <= 0: return
+
+    # 计算除数，使用16位无符号整数
+    divisor: t.CUInt32T = 1193180 / frequency
+
+    # 发送命令字：通道0，先低后高，模式3（方波），二进制计数
+    asm.outb(PIT_COMMAND, 0x36)
+    asm.io_wait()
+
+    # 写入低字节
+    asm.outb(PIT_CHANNEL0, divisor & 0xFF)
+    asm.io_wait()
+
+    # 写入高字节
+    asm.outb(PIT_CHANNEL0, (divisor >> 8) & 0xFF)
+    asm.io_wait()