Add printf and log functions to the grass layer

earth/earth.c

@@ -24,7 +24,7 @@ int main() {
 
  /* Put earth interface to a widely known address */
  memcpy((void*)EARTH_ADDR, &earth, sizeof(earth));
- INFO("Put earth interface at 0x%.8x with size %d", EARTH_ADDR, sizeof(earth));
+ INFO("Put earth interface at 0x%.8x with size 0x%x", EARTH_ADDR, sizeof(earth));
 
  INFO("Start to load the grass layer");
  return 0;
@@ -59,5 +59,11 @@ int earth_init() {
  earth.intr_register = intr_register;
  SUCCESS("Finished initializing the CPU interrupts");
 
+ earth.log.log_info = INFO;
+ earth.log.log_highlight = HIGHLIGHT;
+ earth.log.log_success = SUCCESS;
+ earth.log.log_error = ERROR;
+ earth.log.log_fatal = FATAL;
+
  return 0;
 }

grass/grass.c

@@ -8,7 +8,10 @@
  * spawns some kernel processes, including file system and shell
  */
 
-#include <stdlib.h>
+#include "egos.h"
+#include "grass.h"
+
+struct earth *earth = (void*)EARTH_ADDR;
 
 int global_var1;
 int global_var2;
@@ -21,5 +24,6 @@ int main() {
 
  char* buf = malloc(512);
  free(buf);
+ SUCCESS("Within grass kernel with stack variable @0x%.8x", &buf);
  return 0;
 }

grass/grass.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <stdlib.h>
+
+extern struct earth *earth;
+#define printf earth->tty_write
+
+#define INFO earth->log.log_info
+#define HIGHLIGHT earth->log.log_highlight
+#define SUCCESS earth->log.log_success
+#define ERROR earth->log.log_error
+#define FATAL earth->log.log_fatal

shared/include/egos.h

@@ -1,19 +1,33 @@
 #pragma once
 
+/* Interface between earth and grass */
+
 #define TIMER_INTR_ID 7
 #define QUANTUM_NCYCLES 2000
 #define EARTH_ADDR (0x8004000 - 0x40)
 
 typedef void (*handler_t)(int, void*);
 
+struct dev_log {
+ int (*log_info)(const char *format, ...);
+ int (*log_highlight)(const char *format, ...);
+ int (*log_success)(const char *format, ...);
+ int (*log_error)(const char *format, ...);
+ int (*log_fatal)(const char *format, ...);
+};
+
 struct earth {
  int (*tty_read)(char* buf, int len);
- int (*tty_write)(const char *format, ...); 
+ int (*tty_write)(const char *format, ...);
 
  int (*disk_read)(int block_no, int nblocks, char* dst);
  int (*disk_write)(int block_no, int nblocks, char* src);
 
  int (*intr_enable)();
  int (*intr_disable)();
  int (*intr_register)(int id, handler_t handler);
+
+ struct dev_log log;
 };
+
+/* Interface between grass and apps */