1 files changed, 56 insertions, 0 deletions
diff --git a/devices/uart_16550.h b/devices/uart_16550.h
new file mode 100644
index 0000000..d053985
--- /dev/null
+++ b/devices/uart_16550.h
@@ -0,0 +1,56 @@
+#pragma once
+
+enum uart_16550_offset {
+  Data = 0, // read from receive buffer / write to transmit buffer | BaudDiv_l
+  InterruptControl = 1, // interrupt enable | BaudDiv_h
+  FifoControl = 2,      // interrupt ID and FIFO control
+  LineControl = 3,      // most significant bit is the DLAB
+  ModemControl = 4,
+  LineStatus = 5,
+  ModemStatus = 6,
+  Scratch = 7,
+};
+// Line Control
+// | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+// |dla|   | parity    | s | data  |
+
+enum LineControl {
+  d5bit = 0b00000000, // data bits
+  d6bit = 0b00000001,
+  d7bit = 0b00000010,
+  d8bit = 0b00000011,
+  // none = 0b00000000, // parity bits
+  odd = 0b00001000,
+  even = 0b00011000,
+  mark = 0b00101000,
+  space = 0b00111000,
+  // s1bit = 0b00000000, // stop bits
+  s2bit = 0b00000100, // 1.5 for 5bit data; 2 otherwise
+  dlab = 0b10000000,  // divisor latch access bit
+};
+
+// Line Status Register
+enum LineStatus {
+  DR = 0b00000001,   // data ready: see if there is data to read
+  OE = 0b00000010,   // overrun error: see if there has been data lost
+  PE = 0b00000100,   // parity error: see if there was error in transmission
+  FE = 0b00001000,   // framing error: see if a stop bit was missing
+  BI = 0b00010000,   // break indicator: see if there is a break in data input
+  THRE = 0b00100000, // transmitter holding register empty: see if transmission buffer is empty
+  TEMT = 0b01000000, // transmitter empty: see if transmitter is not doing anything
+  ERRO = 0b10000000, // impending error: see if there is an error with a word in the input buffer
+};
+
+enum UART {
+  COM1 = 0x3f8,
+  COM2 = 0x2f8,
+  COM3 = 0x3E8,
+  COM4 = 0x2E8,
+  COM5 = 0x5F8,
+  COM6 = 0x4F8,
+  COM7 = 0x5E8,
+  COM8 = 0x4E8,
+};
+
+int uart_init(enum UART port);
+int uart_puts(enum UART port, const char *string, int length);