create support for kernel modules (but don't implement them yet)

2 files changed, 40 insertions, 0 deletions

diff --git a/kernel/kernel.c b/kernel/kernel.c
new file mode 100644
index 0000000..753f4a5
--- /dev/null
+++ b/kernel/kernel.c
@@ -0,0 +1,20 @@
+#define UART_BASE 0x10000000  // Example UART address
+
+static inline void putchar(char c) {
+    volatile char *uart = (volatile char *)UART_BASE;
+    *uart = c;
+}
+
+static void print_string(const char *str) {
+    while (*str) {
+        putchar(*str++);
+    }
+}
+
+void kernel_main(void) {
+    print_string("Hello from RISC-V kernel!\n");
+    
+    while (1) {
+        // Wait
+    }
+}
diff --git a/kernel/start.S b/kernel/start.S
new file mode 100644
index 0000000..dce0faa
--- /dev/null
+++ b/kernel/start.S
@@ -0,0 +1,20 @@
+.section .text._start
+.global _start
+.type _start, @function
+
+_start:
+    csrw mstatus, zero
+    csrw mie, zero
+    
+    la sp, __stack_top
+    
+    la t0, __bss_start
+    la t1, __bss_end
+    beq t0, t1, 2f
+1:
+    sw zero, 0(t0)
+    addi t0, t0, 4
+    bltu t0, t1, 1b
+2:
+    call kernel_main
+    j .