Move source files to src/, add Makefile, fix all build and linkage errors, etc.

exosphere/src/uart.c

@@ -0,0 +1,36 @@
+#include "uart.h"
+
+void uart_initialize(uint16_t divider) {
+    /* Setup UART in 16450 mode. We assume the relevant UART clock has been enabled. */
+
+    /* Disable FIFO */
+    UART_IIR_FCR_0 = 0x00;
+
+    /* Set DLAB */
+    UART_LCR_0 = 0x80;
+    UART_THR_DLAB_0_0 = (uint8_t)divider;
+    UART_IER_DLAB_0_0 = (uint8_t)(divider >> 8);
+
+    /* 8N1 mode */
+    UART_LCR_0 = 0x03;
+}
+
+void uart_transmit_char(char ch) {
+    /* Wait for THR to be empty */
+    while (!(UART_LSR_0 & 0x20)) {}
+
+    UART_THR_DLAB_0_0 = ch;
+}
+
+void uart_transmit_str(const char *str) {
+    while (*str) {
+        uart_transmit_char(*str++);
+    }
+}
+
+void uart_transmit_hex(uint32_t value) {
+    for (unsigned int i = 0; i < 8; i++) {
+        uint32_t nibble = (value >> (28 - i * 4)) & 0xF;
+        uart_transmit_char("0123456789ABCDEF"[nibble]);
+    }
+}