From 02f14113cbf14c6f842fb43ecbc68d0c851ef3b0 Mon Sep 17 00:00:00 2001
From: Benji Dial <benji3.141@gmail.com>
Date: Sun, 24 May 2020 11:02:43 -0400
Subject: very basic vga, ata, serial drivers. start of fat and fs drivers

---
 src/kernel/util.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 src/kernel/util.c

(limited to 'src/kernel/util.c')

diff --git a/src/kernel/util.c b/src/kernel/util.c
new file mode 100644
index 0000000..df6e7d8
--- /dev/null
+++ b/src/kernel/util.c
@@ -0,0 +1,100 @@
+#include <stdint.h>
+#include "panic.h"
+#include <stdbool.h>
+
+void memcpy(void *from, void *to, uint32_t n) {
+  panic("Not implemented (memcpy).");
+}
+
+void u32_dec(uint32_t n, uint8_t *b) {
+  if (!n) {
+    *(uint16_t *)b = '0';
+    return;
+  }
+  bool zero = false;
+  for (uint32_t m = 1000000000; m; m /= 10) {
+    uint8_t d = (n / m) % 10;
+    if (zero)
+      *(b++) = d + '0';
+    else if (d) {
+      zero = true;
+      *(b++) = d + '0';
+    }
+  }
+  *b = 0;
+}
+
+void u16_dec(uint16_t n, uint8_t *b) {
+  if (!n) {
+    *(uint16_t *)b = '0';
+    return;
+  }
+  bool zero = false;
+  for (uint32_t m = 10000; m; m /= 10) {
+    uint8_t d = (n / m) % 10;
+    if (zero)
+      *(b++) = d + '0';
+    else if (d) {
+      zero = true;
+      *(b++) = d + '0';
+    }
+  }
+  *b = 0;
+}
+
+void u8_dec(uint8_t n, uint8_t *b) {
+  if (!n) {
+    *(uint16_t *)b = '0';
+    return;
+  }
+  bool zero = false;
+  for (uint32_t m = 100; m; m /= 10) {
+    uint8_t d = (n / m) % 10;
+    if (zero)
+      *(b++) = d + '0';
+    else if (d) {
+      zero = true;
+      *(b++) = d + '0';
+    }
+  }
+  *b = 0;
+}
+
+void u32_hex(uint32_t n, uint8_t *b) {
+  uint8_t m = 28;
+  while (1) {
+    uint8_t d = (n >> m) & 0xf;
+    *(b++) = d >= 10 ? 'a' + d - 10 : '0' + d;
+    if (!m) {
+      *b = 0;
+      return;
+    }
+    m -= 4;
+  }
+}
+
+void u16_hex(uint16_t n, uint8_t *b) {
+  uint8_t m = 12;
+  while (1) {
+    uint8_t d = (n >> m) & 0xf;
+    *(b++) = d >= 10 ? 'a' + d - 10 : '0' + d;
+    if (!m) {
+      *b = 0;
+      return;
+    }
+    m -= 4;
+  }
+}
+
+void u8_hex(uint8_t n, uint8_t *b) {
+  uint8_t m = 4;
+  while (1) {
+    uint8_t d = (n >> m) & 0xf;
+    *(b++) = d >= 10 ? 'a' + d - 10 : '0' + d;
+    if (!m) {
+      *b = 0;
+      return;
+    }
+    m -= 4;
+  }
+}
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