1 files changed, 49 insertions, 0 deletions
diff --git a/devices/uart/uart_16550.h b/devices/uart/uart_16550.h
new file mode 100644
index 0000000..bbeb9b7
--- /dev/null
+++ b/devices/uart/uart_16550.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#include "uart.h"
+
+int uart_thre(unsigned short port);
+void uart_putc(const FILE *self, char a);
+int uart_puts(const FILE *self, const char *string, int length);
+void uart_flush(__attribute__((unused)) const FILE *self);
+
+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 = 0x00, /* 0000 0000  data bits */
+  d6bit = 0x01, /* 0000 0001 */
+  d7bit = 0x02, /* 0000 0010 */
+  d8bit = 0x03, /* 0000 0011 */
+  /* none = 0b00000000, // parity bits */
+  odd = 0x08,   /* 0000 1000 */
+  even = 0x18,  /* 0001 1000 */
+  mark = 0x28,  /* 0010 1000 */
+  space = 0x38, /* 0011 1000 */
+  /* s1bit = 0b00000000, // stop bits */
+  s2bit = 0x04, /* 0000 0100  1.5 for 5bit data; 2 otherwise */
+  dlab = 0x80   /* 1000 0000  divisor latch access bit */
+};
+
+/* Line Status Register */
+enum LineStatus {
+  DR = (1 << 0),   /* data ready: see if there is data to read */
+  OE = (1 << 1),   /* overrun error: see if there has been data lost */
+  PE = (1 << 2),   /* parity error: see if there was error in transmission */
+  FE = (1 << 3),   /* framing error: see if a stop bit was missing */
+  BI = (1 << 4),   /* break indicator: see if there is a break in data input */
+  THRE = (1 << 5), /* transmitter holding register empty: see if transmission buffer is empty */
+  TEMT = (1 << 6), /* transmitter empty: see if transmitter is not doing anything */
+  ERRO = (1 << 7)  /* impending error: see if there is an error with a word in the input buffer */
+};