From 51d5f3c9fda454e78e87e05029a34b56b0815186 Mon Sep 17 00:00:00 2001 From: Siarhei Siamashka Date: Mon, 14 Mar 2011 15:36:07 -0300 Subject: sbc: added "cc" to the clobber list of mmx inline assembly In the case of scale factors calculation optimizations, the inline assembly code has instructions which update flags register, but "cc" was not mentioned in the clobber list. When optimizing code, gcc theoretically is allowed to do a comparison before the inline assembly block, and a conditional branch after it which would lead to a problem if the flags register gets clobbered. While this is apparently not happening in practice with the current versions of gcc, the clobber list needs to be corrected. Regarding the other inline assembly blocks. While most likely it is actually unnecessary based on quick review, "cc" is also added there to the clobber list because it should have no impact on performance in practice. It's kind of cargo cult, but relieves us from the need to track the potential updates of flags register in all these places. --- src/modules/bluetooth/sbc/sbc_primitives_mmx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/modules/bluetooth/sbc/sbc_primitives_mmx.c b/src/modules/bluetooth/sbc/sbc_primitives_mmx.c index d8373b3a..ab89d074 100644 --- a/src/modules/bluetooth/sbc/sbc_primitives_mmx.c +++ b/src/modules/bluetooth/sbc/sbc_primitives_mmx.c @@ -100,7 +100,7 @@ static inline void sbc_analyze_four_mmx(const int16_t *in, int32_t *out, : : "r" (in), "r" (consts), "r" (&round_c), "r" (out), "i" (SBC_PROTO_FIXED4_SCALE) - : "memory"); + : "cc", "memory"); } static inline void sbc_analyze_eight_mmx(const int16_t *in, int32_t *out, @@ -242,7 +242,7 @@ static inline void sbc_analyze_eight_mmx(const int16_t *in, int32_t *out, : : "r" (in), "r" (consts), "r" (&round_c), "r" (out), "i" (SBC_PROTO_FIXED8_SCALE) - : "memory"); + : "cc", "memory"); } static inline void sbc_analyze_4b_4s_mmx(int16_t *x, int32_t *out, @@ -322,7 +322,7 @@ static void sbc_calc_scalefactors_mmx( "r" (&scale_factor[ch][sb]), "r" (&consts), "i" (SCALE_OUT_BITS) - : "memory"); + : "cc", "memory"); } } asm volatile ("emms\n"); -- cgit