new memory and project layout

2026-10-01 12:17:47 +02:00
parent 9b1fcac8ee
commit d19ffc70a1
10 changed files with 397 additions and 272 deletions
@@ -0,0 +1,113 @@
+#include <stdint.h>
+#include "bios.h"
+#include "circ_buf.h"
+
+#define UART_CTC_CARD_BASE 0x20
+#define CTC_BASE (UART_CTC_CARD_BASE + 0x00)
+#define CTC_CHANNEL_0 (CTC_BASE + 0)
+#define CTC_CHANNEL_3 (CTC_BASE + 3)
+#define UART_BASE (UART_CTC_CARD_BASE + 0x04)
+#define UART_CONTROL (UART_BASE + 0)
+#define UART_DATA (UART_BASE + 1)
+
+static volatile uint8_t uart_tx_busy;
+static volatile circular_buffer_t rx_buf;
+static volatile circular_buffer_t tx_buf;
+
+static void uart_kick(void)
+{
+    char c;
+
+    disable_interrupts();
+    if (!uart_tx_busy && buffer_dequeue(&tx_buf, &c)) {
+        uart_tx_busy = 1;
+        io_out(UART_DATA, c);
+        io_out(UART_CONTROL, 0b10110101);
+    }
+    enable_interrupts();
+}
+
+void bios_putc(char c)
+{
+    uint8_t queued;
+
+    do {
+        disable_interrupts();
+        queued = buffer_enqueue(&tx_buf, c);
+        enable_interrupts();
+        if (!queued) uart_kick();
+    } while (!queued);
+    uart_kick();
+}
+
+void bios_puts(const char *s)
+{
+    while (*s) bios_putc(*s++);
+}
+
+uint8_t bios_try_getc(void)
+{
+    char c;
+    uint8_t received;
+
+    disable_interrupts();
+    received = buffer_dequeue(&rx_buf, &c);
+    enable_interrupts();
+    return received ? (uint8_t)c : 0;
+}
+
+char bios_getc(void)
+{
+    uint8_t c;
+
+    do {
+        c = bios_try_getc();
+    } while (!c);
+    return (char)c;
+}
+
+void bios_flush(void)
+{
+    while (uart_tx_busy || !buffer_is_empty(&tx_buf)) uart_kick();
+}
+
+void bios_init(void)
+{
+    buffer_init(&rx_buf);
+    buffer_init(&tx_buf);
+
+    io_out(CTC_CHANNEL_0, 0x57);
+    io_out(CTC_CHANNEL_0, 13);
+    io_out(CTC_CHANNEL_3, 0b11001111);
+    io_out(CTC_CHANNEL_3, 1);
+    io_out(CTC_CHANNEL_0, 0x00);
+    io_out(CTC_CHANNEL_0, 0x40);
+
+    uart_tx_busy = 0;
+    io_out(UART_CONTROL, 0b00000011);
+    io_out(UART_CONTROL, 0b10010101);
+    enable_interrupts();
+}
+
+void uart_interrupt(void)
+{
+    uint8_t status = io_in(UART_CONTROL);
+
+    if ((status & 0x21) != 0) {
+        char c = io_in(UART_DATA);
+        if ((status & 0x01) != 0) buffer_enqueue(&rx_buf, c);
+    }
+    if ((status & 0x02) != 0 && uart_tx_busy) {
+        char c;
+        if (buffer_dequeue(&tx_buf, &c)) {
+            io_out(UART_DATA, c);
+        } else {
+            io_out(UART_CONTROL, 0b10010101);
+            uart_tx_busy = 0;
+        }
+    }
+}
+
+void ctc_interrupt(void)
+{
+}