Lecture 102 - Implementing system get key in stdlib

programs/blank/blank.c

@@ -3,6 +3,12 @@ int main(int argc, char** argv)
 {
     print("Hello how are you!\n");
 
-    while(1) {}
+    while(1) 
+    {
+        if (getkey() != 0)
+        {
+            print("key was pressed\n");
+        }
+    }
     return 0;
 }

programs/stdlib/src/peachos.asm

@@ -1,6 +1,7 @@
 [BITS 32]
 
 global print:function
+global getkey:function
 
 ; void print(const char* filename)
 print:
@@ -10,6 +11,14 @@ print:
     mov eax, 1 ; Command print
     int 0x80
     add esp, 4
-    
     pop ebp
-    ret
+    ret
+
+; int getkey()
+getkey:
+    push ebp
+    mov ebp, esp
+    mov eax, 2 ; Command getkey
+    int 0x80
+    pop ebp
+    ret

programs/stdlib/src/peachos.h

@@ -1,5 +1,6 @@
 #ifndef PEACHOS_H
 #define PEACHOS_H
 void print(const char* filename);
+int getkey();
 
 #endif