From f0087f06aad7c35d5c95421e661f0852814cf90a Mon Sep 17 00:00:00 2001 From: Andree Buschmann Date: Sun, 22 Jun 2008 09:11:06 +0000 Subject: Small correction to avoid overflow within calculate_V()-function. Re-enable full precision for ARM as speed-optimized version is not that much faster anymore. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17750 a1c6a512-1295-4272-9138-f99709370657 --- apps/codecs/libmusepack/mpc_config.h | 2 +- apps/codecs/libmusepack/synth_filter.c | 6 ++++-- 2 files changed, 5 insertions(+), 3 deletions(-) diff --git a/apps/codecs/libmusepack/mpc_config.h b/apps/codecs/libmusepack/mpc_config.h index 6993775703..fa78a46695 100755 --- a/apps/codecs/libmusepack/mpc_config.h +++ b/apps/codecs/libmusepack/mpc_config.h @@ -37,7 +37,7 @@ #if defined(CPU_COLDFIRE) // do nothing #elif defined(CPU_ARM) - #define OPTIMIZE_FOR_SPEED + //#define OPTIMIZE_FOR_SPEED #else #define OPTIMIZE_FOR_SPEED #endif diff --git a/apps/codecs/libmusepack/synth_filter.c b/apps/codecs/libmusepack/synth_filter.c index 7d83c752e7..fb956fbff4 100644 --- a/apps/codecs/libmusepack/synth_filter.c +++ b/apps/codecs/libmusepack/synth_filter.c @@ -115,8 +115,8 @@ static const MPC_SAMPLE_FORMAT Di_opt [512] ICONST_ATTR = { #undef D -// needed to prevent from internal overflow in calculate_V -#define OVERFLOW_FIX 1 +// needed to prevent from internal overflow in calculate_V (see below) +#define OVERFLOW_FIX 2 // V-coefficients were expanded (<<) by V_COEFFICIENT_EXPAND #define V_COEFFICIENT_EXPAND 27 @@ -128,6 +128,7 @@ static const MPC_SAMPLE_FORMAT Di_opt [512] ICONST_ATTR = { #define MPC_MULTIPLY_V(sample, vcoef) ( MPC_SHR_RND(sample, 12) * vcoef ) // pre- and postscale are used to avoid internal overflow in synthesis calculation + // samples are s15.0, v-coefs are 4.12 -> internal format is s19.12 #define MPC_MULTIPLY_V_PRESCALE(sample, vcoef) ( MPC_SHR_RND(sample, (12+OVERFLOW_FIX)) * vcoef ) #define MPC_MULTIPLY_V_POSTSCALE(sample, vcoef) ( MPC_SHR_RND(sample, (12-OVERFLOW_FIX)) * vcoef ) #define MPC_V_POSTSCALE(sample) (sample< internal format is s19.12 #define MPC_MULTIPLY_V_PRESCALE(sample, vcoef) ( (MPC_MULTIPLY_FRACT(sample, vcoef)) << (32-V_COEFFICIENT_EXPAND-OVERFLOW_FIX) ) #define MPC_MULTIPLY_V_POSTSCALE(sample, vcoef) ( (MPC_MULTIPLY_FRACT(sample, vcoef)) << (32-V_COEFFICIENT_EXPAND+OVERFLOW_FIX) ) #define MPC_V_POSTSCALE(sample) (sample<