Clean up printing code in buildtest

buildtest.c

@@ -1,6 +1,22 @@
 #include "int.h"
 #include "sys.h"
 
+#define print(str) write(STDOUT, str, (sizeof str) - 1)
+void printhex(uint64_t num) {
+  char msg[17] = {' '};
+  msg[16] = '\n';
+  for (int i = 0; i < 16; ++i) {
+    char nibble = (num >> ((15 - i) * 4)) & 0xf;
+    char c;
+    if (nibble > 9) {
+      c = nibble + '7';
+    } else {
+      c = nibble + '0';
+    }
+    msg[i] = c;
+  }
+  write(STDOUT, msg, 17);
+}
 
 int main(int argc, char* argv[]) {
   // Test the write syscall
@@ -17,16 +33,7 @@ int main(int argc, char* argv[]) {
   // Test the fork syscall
   uint64_t pid = fork();
   // Print the pid in hex
-  char msg[17] = {' '};
-  msg[16] = '\n';
-  for(int i = 0; i < 16; ++i) {
-    char nibble = (pid >> ((15 - i) * 4)) & 0xf;
-    char c;
-    if (nibble > 9) {c = nibble + '7';}
-    else {c = nibble + '0';}
-    msg[i] = c;
-  }
-  write(STDOUT, msg, 17);
+  printhex(pid);
 
   // Child process exits
   if(pid == 0) return 0;
@@ -37,7 +44,7 @@ int main(int argc, char* argv[]) {
   char input_buffer[INPUT_BUFFER_LEN] = {0};
   int32_t fout = openc("outfile", O_RDWR | O_CREAT | O_TRUNC, 0664);
 
-  write(STDOUT, "Enter some text:", 16);
+  print("Enter some text:");
   intptr_t n_read = read(STDIN, input_buffer, INPUT_BUFFER_LEN);
   write(STDOUT, input_buffer, n_read);
   if(fout > 0) {
@@ -55,15 +62,15 @@ int main(int argc, char* argv[]) {
       i = read(file, input_buffer, INPUT_BUFFER_LEN);
     }
   } else {
-    write(STDOUT, "Could not open /proc/version\n", 29);
+    print("Could not open /proc/version\n");
   }
 
   // Test sleep
-  write(STDOUT, "Sleeping for 5 secs\n", 20);
+  print("Sleeping for 5 secs\n");
   struct timespec sleeptime;
   sleeptime.tv_sec = 5;
   while (nanosleep(&sleeptime, &sleeptime) != 0) {}
-  write(STDOUT, "DONE\n", 5);
+  print("DONE\n");
 
   return 69;
 }