From cce35f64d37b091c4525f63a9ec9dc384bd10b54 Mon Sep 17 00:00:00 2001
From: Alan Jian <alanjian85@outlook.com>
Date: Sat, 30 Mar 2024 13:37:27 +0800
Subject: [PATCH] Implement integer format specifiers

---
 include/types.h |  2 +-
 src/kmain.c     |  1 +
 src/kprintf.c   | 70 +++++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/include/types.h b/include/types.h
index 6083005..8e92ef9 100644
--- a/include/types.h
+++ b/include/types.h
@@ -15,6 +15,6 @@ typedef int32_t i32;
 typedef int64_t i64;
 
 typedef uintptr_t usize;
-typedef uintptr_t ssize;
+typedef intptr_t ssize;
 
 #endif // TYPES_H_
diff --git a/src/kmain.c b/src/kmain.c
index b8f9e9a..b6343a6 100644
--- a/src/kmain.c
+++ b/src/kmain.c
@@ -1,5 +1,6 @@
 #include <attribs.h>
 #include <kprintf.h>
+#include <limits.h>
 #include <types.h>
 
 noreturn void kmain(void) {
diff --git a/src/kprintf.c b/src/kprintf.c
index 3163c1e..a51eb2a 100644
--- a/src/kprintf.c
+++ b/src/kprintf.c
@@ -1,7 +1,50 @@
 #include <stdarg.h>
-
+#include <types.h>
 #include <uart.h>
 
+static void print_usize(usize val, i32 radix) {
+    if (val == 0) {
+        uart_putc('0');
+        return;
+    }
+
+    char buf[(usize) (sizeof(val) * 8.0 / 3 + 1)];
+    usize pos = sizeof(buf);
+
+    while (val != 0) {
+        pos--;
+        u8 digit = val % radix;
+        if (digit < 10)
+            buf[pos] = digit + '0';
+        else
+            buf[pos] = digit - 10 + 'a';
+        val /= radix;
+    }
+
+    for (usize i = pos; i < sizeof(buf); i++)
+        uart_putc(buf[i]);
+}
+
+static void print_ssize(ssize val, i32 radix) {
+    if (val < 0) {
+        uart_putc('-');
+        val = -val;
+    }
+
+    print_usize(val, radix);
+}
+
+static void print_ptr(void *ptr) {
+    for (usize i = sizeof(ptr) * 2; i > 0; i--) {
+        u8 nibble = (usize) ptr >> ((i - 1) * 4) & 0xF;
+        if (nibble < 10) {
+            uart_putc(nibble + '0');
+        } else {
+            uart_putc(nibble - 10 + 'a');
+        }
+    }
+}
+
 void kprintf(const char *fmt, ...) {
     va_list args;
     va_start(args, fmt);
@@ -16,17 +59,34 @@ void kprintf(const char *fmt, ...) {
         fmt++;
 
         switch (*fmt++) {
-        case 'c': {
-            char c = va_arg(args, int);
-            uart_putc(c);
+        case '%':
+            uart_putc('%');
+            break;
+        case 'c':
+            uart_putc(va_arg(args, int));
             break;
-        }
         case 's': {
             const char *s = va_arg(args, const char *);
             for (; *s; s++)
                 uart_putc(*s);
             break;
         }
+        case 'd':
+        case 'i':
+            print_ssize(va_arg(args, int), 10);
+            break;
+        case 'o':
+            print_usize(va_arg(args, unsigned), 8);
+            break;
+        case 'x':
+            print_usize(va_arg(args, unsigned), 16);
+            break;
+        case 'u':
+            print_usize(va_arg(args, unsigned), 10);
+            break;
+        case 'p':
+            print_ptr(va_arg(args, void *));
+            break;
         }
     }