Fix unified syntax in ARM inline assembly

GCC 4.9 always emits assembly with divided syntax. Setting unified
syntax in inline assembly causes the assembler to complain about
GCC's generated code, because the directive extends past the scope
of the inline asm. Fix this by setting divided mode at the end of
the inline assembly block.

The assembler directives are hidden behind macros because later
versions of GCC won't need this workaround: they can be told to
use the unified syntax with -masm-syntax-unified.

Change-Id: Ic09e729e5bbb6fd44d08dac348daf6f55c75d7d8

1 files changed, 2 insertions, 1 deletions

diff --git a/firmware/target/arm/pcm-telechips.c b/firmware/target/arm/pcm-telechips.c
index 747765d8fb..45044bc664 100644
--- a/firmware/target/arm/pcm-telechips.c
+++ b/firmware/target/arm/pcm-telechips.c
@@ -218,7 +218,7 @@ void fiq_handler(void)
      * r0-r3 and r12 is a working register.
      */
     asm volatile (
-        ".syntax unified             \n"
+        BEGIN_ARM_ASM_SYNTAX_UNIFIED
         "sub     lr, lr, #4          \n"
         "stmfd   sp!, { r0-r3, lr }  \n" /* stack scratch regs and lr */
         "mov     r14, #0             \n" /* Was the callback called? */
@@ -274,6 +274,7 @@ void fiq_handler(void)
         "bhi     .fill_fifo          \n" /* not stop and enough? refill */
         "ldmfd   sp!, { r0-r3, pc }^ \n" /* exit */
         ".ltorg                      \n"
+        END_ARM_ASM_SYNTAX_UNIFIED
         : : "i"(PCM_DMAST_OK), "i"(PCM_DMAST_STARTED)
     );
 }