Fix Klocwork#137: Non-void function does not return value

Move getTimeStampClks() function to an *.S file
It is fully implemented in assembly and we take care of returning value by
filling in the proper value in the proper registers.

Signed-off-by: Bogdan Pricop <[email protected]>

Author: Bogdan Pricop

.gitignore

@@ -5,3 +5,4 @@
 *.swp
 *.bin
 .*
+cscope.*

cores/arduino/utils.S

@@ -0,0 +1,43 @@
+/*
+Copyright (c) 2015 Intel Corporation.  All right reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+*/
+
+
+.globl getTimeStampClks
+.type getTimeStampClks, %function
+
+getTimeStampClks:
+   /* Disable interrupts - we don't want to be disturbed */
+   clri r2
+   /* Load in r1 value of timer0_overflows */
+   ld r1, [timer0_overflows]
+   /* Read COUNT0 register */
+   lr r0, [0x21]
+   /* Read CONTROL0 register */
+   lr r3, [0x22]
+   /* If CONTROL0.IP is set COUNT0 reached LIMIT0 => r1 value might not be
+    * accurate => read COUNT0 again */
+   bbit0.nt r3, 3, end
+   /* Read COUNT0 again*/
+   lr r0, [0x21]
+   /* Timer0 overflowed => timer0_overflows++ */
+   add r1, r1, 1
+   /***/
+end:
+    seti r2
+

cores/arduino/wiring.c

@@ -29,32 +29,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 #define FREQ_MHZ	((ARCV2_TIMER0_CLOCK_FREQ)/1000000)
 static const uint64_t	 MS_TO_CLKS = (FREQ_MHZ * 1000);
 
-static uint64_t getTimeStampClks(void)
-{
-    __asm__ volatile (
-   /* Disable interrupts - we don't want to be disturbed */
-   "clri r2			    \n\t"
-   /* Load in r1 value of timer0_overflows */
-   "ld r1, %0			    \n\t"
-   /* Read COUNT0 register */
-   "lr r0, [0x21]		    \n\t"
-   /* Read CONTROL0 register */
-   "lr r3, [0x22]		    \n\t"
-   /* If CONTROL0.IP is set COUNT0 reached LIMIT0 => r1 value might not be
-    * accurate => read COUNT0 again */
-   "bbit0.nt r3, 3, end	    \n\t"
-   /* Read COUNT0 again*/
-   "lr r0, [0x21]		    \n\t"
-   /* Timer0 overflowed => timer0_overflows++ */
-   "add r1, r1, 1		    \n\t"
-   /***/
-   "end:			    \n\t"
-   "seti r2			    \n\t"
-   : /* Output parameters and their constraints */
-   :  "m"(timer0_overflows)   /* Input parameters and their constraints */
-   :  "r0", "r1", "r2", "r3" /* Killed registers */
-   );
-}
+extern uint64_t getTimeStampClks(void);
 
 void delay(uint32_t msec)
 {

platform.txt

@@ -59,6 +59,9 @@ build.usb_manufacturer="Unknown"
 ## Compile c files
 recipe.c.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.c.flags} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.c.extra_flags} {build.extra_flags} {includes} "{source_file}" -o "{object_file}"
 
+## Compile S files
+recipe.S.o.pattern="{compiler.path}{compiler.c.cmd}" {compiler.c.flags} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.c.extra_flags} {build.extra_flags} {includes} "{source_file}" -o "{object_file}"
+
 ## Compile c++ files
 recipe.cpp.o.pattern="{compiler.path}{compiler.cpp.cmd}" {compiler.cpp.flags} -DF_CPU={build.f_cpu} -DARDUINO={runtime.ide.version} -DARDUINO_{build.board} -DARDUINO_ARCH_{build.arch} {compiler.cpp.extra_flags} {build.extra_flags} {includes} "{source_file}" -o "{object_file}"