detect absence of fmax() in libm and activate fallback for generic_set_frequency()

git-svn-id: https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk@1282 b68d4a1b-bc3d-0410-92ed-d4ac073336b7

jtag/ChangeLog

@@ -1,5 +1,9 @@
 2008-06-11  Arnim Laeuger  <arniml@users.sourceforge.net>
 
+   * src/tap/cable/generic.c (fmax): define fallback in case libm doesn't
+     provide fmax()
+   * configure.ac: detect availability of fmax() in libm
+
    * src/bus/bf548_ezkit.c, src/bus/ppc405ep.c, src/bus/sh7727.c,
      src/bus/sa1110.c, src/bus/ppc440gx_ebc8.c, src/bus/tx4925.c,
      src/bus/sh7750r.c, src/bus/pxa2x0.c, src/bus/bf533_stamp.c,

jtag/configure.ac

@@ -540,6 +540,13 @@ AS_IF([test "x$relocatable" = xyes], [
   AM_CONDITIONAL(JTAG_RELOCATABLE, false)
 ])
 
+
+dnl Is fmax() provided by libm?
+AC_CHECK_LIB([m], [fmax], [
+  AC_DEFINE(HAVE_FMAX, 1, [Define if -lm provides fmax()])
+])
+
+
 AC_OUTPUT
 
 dnl

jtag/src/tap/cable/generic.c

@@ -39,6 +39,13 @@
 
 #include <cmd.h>
 
+
+#ifndef HAVE_FMAX
+/* workaround for libm implementations that don't provide the fmax() function */
+#define fmax(_f1_,_f2_) ( (_f1_) > (_f2_) ? (_f1_) : (_f2_) )
+#endif
+
+
 #undef VERBOSE
 
 #ifdef VERBOSE