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authorPavel Pisa <pisa@cmp.felk.cvut.cz>2015-11-28 12:01:36 +0100
committerGedare Bloom <gedare@rtems.org>2015-12-01 21:09:25 -0500
commit2a9db262a2bbf5b0cf0c904431afb7af172bb7eb (patch)
treec5f81a76464cea771f82aa7a417853ced8f68cf0
parentFix _Assert() statement (diff)
downloadrtems-2a9db262a2bbf5b0cf0c904431afb7af172bb7eb.tar.bz2
bsp/tms570: ensure that linker symbol comparison to NULL is not optimized out.
Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
-rw-r--r--c/src/lib/libbsp/arm/tms570/startup/bspstart.c14
1 files changed, 12 insertions, 2 deletions
diff --git a/c/src/lib/libbsp/arm/tms570/startup/bspstart.c b/c/src/lib/libbsp/arm/tms570/startup/bspstart.c
index b7e2b62591..7c1e9a17bf 100644
--- a/c/src/lib/libbsp/arm/tms570/startup/bspstart.c
+++ b/c/src/lib/libbsp/arm/tms570/startup/bspstart.c
@@ -32,6 +32,9 @@
void bsp_start( void )
{
+ void *need_remap_ptr;
+ unsigned int need_remap_int;
+
#if BYTE_ORDER == BIG_ENDIAN
/*
* If CPU is big endian (TMS570 family variant)
@@ -65,9 +68,16 @@ void bsp_start( void )
* SRAM then it leads to CPU error halt.
*
* So use of POM to replace jumps to vectors target
- * addresses seems to be the best option.
+ * addresses seems to be the best option for now.
+ *
+ * The passing of linker symbol (represented as start address
+ * of global array) through dummy asm block ensures that C compiler
+ * cannot optimize comparison out on premise that reference cannot
+ * evaluate to NULL definition in standard.
*/
- if ( (uintptr_t)bsp_start_vector_table_begin != 0 ) {
+ need_remap_ptr = bsp_start_vector_table_begin;
+ asm volatile ("\n": "=r" (need_remap_int): "0" (need_remap_ptr));
+ if ( need_remap_int != 0 ) {
tms570_pom_remap();
}