From 38610cd06dc0b5a3a4ee46f5fe7c341191aa2bc1 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Sat, 21 Dec 2019 12:25:14 +0100
Subject: Some userspace improvements

GAS is bad, NASM is awesome.
---
 src/userspace/mlibc/string/strlen.c | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

(limited to 'src/userspace/mlibc/string')

diff --git a/src/userspace/mlibc/string/strlen.c b/src/userspace/mlibc/string/strlen.c
index 133ee3d..f6a06a4 100644
--- a/src/userspace/mlibc/string/strlen.c
+++ b/src/userspace/mlibc/string/strlen.c
@@ -2,7 +2,33 @@
 
 size_t strlen(const char *str)
 {
-    size_t len = 0;
-    while (str[len]) len++;
-    return len;
+    const char *char_ptr;
+    const unsigned long int *longword_ptr;
+    unsigned long int longword, himagic, lomagic;
+
+    for (char_ptr = str; ((unsigned long int) char_ptr & (sizeof(longword) - 1)) != 0; ++char_ptr)
+        if (*char_ptr == '\0')
+            return char_ptr - str;
+
+    longword_ptr = (unsigned long int *) char_ptr;
+
+    himagic = 0x80808080L;
+    lomagic = 0x01010101L;
+
+    for (;;) {
+        longword = *longword_ptr++;
+
+        if (((longword - lomagic) & himagic) != 0) {
+            const char *cp = (const char *) (longword_ptr - 1);
+
+            if (cp[0] == 0)
+                return cp - str;
+            if (cp[1] == 0)
+                return cp - str + 1;
+            if (cp[2] == 0)
+                return cp - str + 2;
+            if (cp[3] == 0)
+                return cp - str + 3;
+        }
+    }
 }
\ No newline at end of file
-- 
cgit v1.2.3