添加rtthread相关代码

riscv/startup/main.c

@@ -0,0 +1,67 @@
+#include "stdint.h"
+#include "stdio.h"
+#include "stdarg.h"
+#include "head.h"
+
+#define PRINT_BASE_ADDR *(uint8_t *)0x40000000
+
+int my_putc(int c) {
+  PRINT_BASE_ADDR = c;
+  return c;
+}
+
+
+int my_puts(const char *s,int len) {
+  for (int i = 0;i < len;i++) {
+    my_putc(s[i]);
+  }
+  return 0;
+}
+
+static char g_print_buff[1024];
+int my_printf(const char* fmt, ...) {
+  int len = 0;
+  va_list args;
+  va_start(args, fmt);
+  len = vsnprintf(g_print_buff, 1024, fmt, args);
+  va_end(args);
+  my_puts(g_print_buff, len);
+  return len;
+}
+
+
+
+
+int add(int a, int b) {
+  return a+b;
+}
+
+
+char g_string[] = "string from ram";
+
+
+int main()
+{
+  int a=1;
+  int b=2;
+  typedef void (*fun_t)(void);
+  fun_t fun = (fun_t)0;
+  set_csr(mstatus, 0x00000008);
+  set_csr(mie, (1 << 3) | (1 << 7));
+  set_csr(mip, (1 << 3));
+  fun();
+  int c = add(a, b);
+  my_printf("Hello World! %s\n", "Andy");
+  my_printf("add(%d, %d)=%d\n", a, b, c);
+  a = 67;b = -78;
+  fun=(fun_t)0xff000000;
+  fun();
+  my_printf("mul(%d, %d)=%d\n", a, b, a * b);
+  my_printf("ram_val test: %s\n", g_string);
+  cpu_test();
+
+  my_printf("enter while 1\n");
+  while (1) {
+  }
+  return 0;
+}