LibM: Implement sqrt()

Use the x87 fsqrt instruction for that.

We cannot use __builtin_sqrt(), since GCC expands it into
a sqrt() call, so we just loop endlessly.

1 files changed, 4 insertions, 2 deletions

diff --git a/Libraries/LibM/math.cpp b/Libraries/LibM/math.cpp
index 8d0cc11135..52170f23dc 100644
--- a/Libraries/LibM/math.cpp
+++ b/Libraries/LibM/math.cpp
@@ -58,9 +58,11 @@ double tan(double angle)
     return ampsin(angle) / ampsin(M_PI_2 + angle);
 }
 
-double sqrt(double)
+double sqrt(double x)
 {
-    ASSERT_NOT_REACHED();
+    double res;
+    __asm__("fsqrt" : "=t"(res) : "0"(x));
+    return res;
 }
 
 double sinh(double)