sdcc-3.9.0 fork implementing GNU assembler syntax

This fork aims to provide better support for stm8-binutils

1 files changed, 61 insertions, 0 deletions

diff --git a/device/lib/sqrtf.c b/device/lib/sqrtf.c
new file mode 100644
index 0000000..b6bee13
--- /dev/null
+++ b/device/lib/sqrtf.c
@@ -0,0 +1,61 @@
+/*-------------------------------------------------------------------------
+   sqrtf.c - Computes square root of a 32-bit float as outlined in [1]
+
+   Copyright (C) 2001, 2002, Jesus Calvino-Fraga, jesusc@ieee.org
+
+   This library is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 2, or (at your option) any
+   later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this library; see the file COPYING. If not, write to the
+   Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA.
+
+   As a special exception, if you link this library with other files,
+   some of which are compiled with SDCC, to produce an executable,
+   this library does not by itself cause the resulting executable to
+   be covered by the GNU General Public License. This exception does
+   not however invalidate any other reasons why the executable file
+   might be covered by the GNU General Public License.
+-------------------------------------------------------------------------*/
+
+/* [1] William James Cody and W.  M.  Waite.  _Software manual for the
+   elementary functions_, Englewood Cliffs, N.J.:Prentice-Hall, 1980. */
+
+/* Version 1.0 - Initial release */
+
+#include <math.h>
+#include <errno.h>
+
+float sqrtf(float x) _FLOAT_FUNC_REENTRANT
+{
+    float f, y;
+    int n;
+
+    if (x==0.0) return x;
+    else if (x==1.0) return 1.0;
+    else if (x<0.0)
+    {
+        errno=EDOM;
+        return 0.0;
+    }
+    f=frexpf(x, &n);
+    y=0.41731+0.59016*f; /*Educated guess*/
+    /*For a 24 bit mantisa (float), two iterations are sufficient*/
+    y+=f/y;
+    y=ldexpf(y, -2) + f/y; /*Faster version of 0.25 * y + f/y*/
+
+    if (n&1)
+    {
+        y*=0.7071067812;
+        ++n;
+    }
+    return ldexpf(y, n/2);
+}