puts optional arguments and documentation

Makefile

@@ -29,7 +29,7 @@ VPATH := $(SRC_DIRS)
 all: clean kernel.bin qemu
 
 # Assembly start.o goes to build/
-$(OUT_DIR)start.o: kernel/start.S
+$(OUT_DIR)start.o: kernel/start.s
 	@mkdir -p $(OUT_DIR)
 	$(AS) -c $< -o $@
 
@@ -53,4 +53,4 @@ qemu:
 	@echo "Press Ctrl-A then X to exit QEMU"
 	@qemu-system-arm -M versatilepb -nographic -kernel $(OUT_DIR)kernel.bin
 
-.PHONY: all clean qemu
+.PHONY: all clean qemu

doc/.gitignore

@@ -1,4 +1,4 @@
-# esclude the /bin directory
+# exclude the /bin directory
 # This is the directory where the compiled files are stored
 # It is not necessary to include it in the repository
-/bin
+/bin

doc/contents/puts.tex

@@ -0,0 +1,60 @@
+\documentclass{article}
+\usepackage{listings}
+\usepackage{geometry}
+\geometry{margin=1in}
+\title{I/O API}
+\date{}
+\begin{document}
+
+\maketitle
+
+\section*{puts(char *s, ...)}
+\subsection*{Description}
+Sends a null-terminated format string over UART. If an incorrect datatype is given for a format specifier, \underline{the behavior is undefined}. If a format specifier is given without a matching argument, it is simply skipped when the string is outputted. The following format specifiers are supported:
+
+\begin{itemize}
+  \item \textbf{\%c}: Expects a single character.
+  \item \textbf{\%s}: Expects a null-terminated string.
+  \item \textbf{\%d}: For 32-bit signed integers in the range \texttt{-2147483648} to \texttt{2147483647}.
+  \item \textbf{\%ld}: For 64-bit signed integers in the range \texttt{-9223372036854775808} to \texttt{9223372036854775807}, excluding the range specified above, for \textbf{\%d}.
+  \item \textbf{\%lu}: For 64-bit unsigned integers in the range \texttt{2147483648} to \texttt{18446744073709551615}.
+  \item \textbf{\%x} and \textbf{\%X}: For 32-bit unsigned integers in the range \texttt{0} to \texttt{2147483647}, where the case of \texttt{x} determines the case of the hexadecimal digits (\texttt{a-f} or \texttt{A-F}).
+  \item \textbf{\%lx} and \textbf{\%lX}: For 64-bit unsigned integers printed in hexadecimal format. Has the same range as \textbf{\%lu}. The case of \texttt{x} determines the case of the hexadecimal digits (\texttt{a-f} or \texttt{A-F}).
+  \item \textbf{\%\%}: Outputs a '\%'.
+\end{itemize}
+
+\begin{flushleft}
+All the ranges specified above are inclusive. Also, note that integers in the range \texttt{-2147483648} to \texttt{2147483647} are passed as 32 bit integers and any integers not part of this range are passed as 64 bit integers \underline{by default}.
+If desired, integers of this range can be cast as \texttt{long long} or \texttt{unsigned long long}
+\newline
+for use with the format specifiers prefixed by \textbf{l}(ell).
+\end{flushleft}
+
+\subsection*{Examples}
+\begin{lstlisting}[language=C,showstringspaces=false]
+// Printing long long integers
+puts("%lu %ld %ld\n", 18446744073709551615, -9223372036854775808, 
+9223372036854775807);
+
+// Printing 32-bit signed integers
+puts("%d %d\n", 2147483647, -2147483648);
+
+// Printing 32-bit unsigned integers
+puts("%x %x %X %X\n", 2147483647, 1234, 2147483647, 1234);
+// Output: 7fffffff 4d2 7FFFFFFF 4D2
+
+// Printing unsigned long long integers in hex
+puts("%lX %lx\n", 0x123456789ABCDEF0, 9223372036854775809);
+// Output: 123456789ABCDEF0 8000000000000001
+
+// Printing a character
+puts("Name: %c\n", 'b');
+
+// Printing a string
+puts("Hello %s\n", "World");
+
+// Printing a '%'
+puts("100%%\n");
+\end{lstlisting}
+
+\end{document}

doc/preamble/macros.tex

@@ -109,4 +109,4 @@
 }{%
   \end{quote}\par\medskip
 }
-\makeatother
+\makeatother

include/printf.h

@@ -1,16 +1,20 @@
 #ifndef PRINTF_H
 #define PRINTF_H
 
+#include <stdarg.h>
 #include <stddef.h>
+#include <stdbool.h>
 
 #ifdef __cplusplus
-extern "C" {
+extern "C"
+{
 #endif
 
-void putc(char c);
-void puts(const char *s);
-char getc(void);
-void getlines(char *restrict buffer, size_t length);
+    void putc(char c);
+    void puts(const char *s);
+    void printf(char *s, ...);
+    char getc(void);
+    void getlines(char *restrict buffer, size_t length);
 
 #ifdef __cplusplus
 }

kernel/kernel.c

@@ -1,4 +1,5 @@
 #include <stdbool.h>
+#include <stddef.h>
 
 #include "printf.h"
 #include "clear.h"
@@ -14,8 +15,7 @@ static const char *banner[] = {
     "\r\n",
     "Welcome to your own little Astra world!\r\n",
     "Type away, explore, have fun.\r\n",
-    "\r\n"
-};
+    "\r\n"};
 
 // Initializes and prints the welcome banner.
 static void init_message(void)
@@ -32,41 +32,50 @@ void kernel_main(void)
     clear();
 
     init_message();
-    puts("AstraKernel is running...\r\n");
-    puts("Press Ctrl-A and then X to exit QEMU.\r\n");
-    puts("\r\n");
+    printf("AstraKernel is running...\r\n");
+    printf("Press Ctrl-A and then X to exit QEMU.\r\n");
+    printf("\r\n");
 
     char input_buffer[100];
 
     bool is_running = true;
     while (is_running)
     {
         input_buffer[0] = '\0'; // Clear the input buffer
-        puts("AstraKernel > ");
+        printf("AstraKernel > ");
         getlines(input_buffer, sizeof(input_buffer));
-        
-        puts("\r\n");
+
+        printf("\r\n");
 
         switch (input_buffer[0])
         {
         case 'h': // Check for help command
-            puts("\nHelp: Press 'q' to exit, 'h' for help.\r\n");
+            printf("\nHelp:\n 'q' to exit\n 'h' for help\n 'c' to clear screen\n 't' to print current time\n 'd' to print current date\r\n");
+            break;
+        case 'e': // TODO: This is for testing purposes. Remove once not needed
+            printf("%ld %ld %ld\n", 0, -9223372036854775808, 9223372036854775807);
+            printf("%d %d\n", 2147483647, -2147483648);
+            printf("%x %lx %lX %X\n", 2147483647, 2147483649, 2147483648, 1234);
+            printf("%lX %x %lx\n", 0x123456789abcdef0, 1234, 9223372036854775809);
+            printf("Name: %c\n", 'b');
+            printf("Hello %s\n", "World");
+            printf("100%%\n");
             break;
         case 'q': // Check for exit command
-            puts("Exiting...\r\n");
+            printf("Exiting...\r\n");
             is_running = false;
             break;
-        case 'c': // Cjeck for clear screen command
+        case 'c': // Check for clear screen command
             clear();
             break;
-        case 't':                               // Check for time command
-            puts("Current time: 12:00 PM\r\n"); // TO-DO: Implement real time check
+        case 't':                                 // Check for time command
+            printf("Current time: 12:00 PM\r\n"); // TO-DO: Implement real time check
             break;
-        case 'd':                                 // Check for date command
-            puts("Current date: 2023-10-01\r\n"); // TO-DO: Implement real date check
+        case 'd':                                   // Check for date command
+            printf("Current date: 2023-10-01\r\n"); // TO-DO: Implement real date check
             break;
         default:
-            puts("Unknown command. Type 'h' for help.\r\n");
+            printf("Unknown command. Type 'h' for help.\r\n");
             break;
         }
     }

user/clear.c

@@ -3,6 +3,6 @@
 // Clears the terminal screen and moves the cursor to the home position.
 void clear(void)
 {
-  puts("\x1B[2J");
-  puts("\x1B[H");
+  printf("\x1B[2J");
+  printf("\x1B[H");
 }