From: Peter Meerwald <pmeerw@debian> building PA with -O0 leads to test failure in mix-test on i386 issue reported by Felipe, see http://lists.freedesktop.org/archives/pulseaudio-discuss/2014-August/021406.html the problem is the value 0xbeffbd7f: when byte-swapped it becomes 0x7fbdffbe and according to IEEE-754 represents a signalling NaN (starting with s111 1111 10, see http://en.wikipedia.org/wiki/NaN) when this value is assigned to a floating point register, it becomes 0x7ffdffbe, representing a quiet NaN (starting with s111 1111 11) -- a signalling NaN is turned into a quiet NaN! so PA_FLOAT32_SWAP(PA_FLOAT32_SWAP(x)) != x for certain values, uhuh! the following test code can be used; due to volatile, it will always demonstrate the issue; without volatile, it depends on the optimization level (i386, 32-bit, gcc 4.9): // snip static inline float PA_FLOAT32_SWAP(float x) { union { float f; uint32_t u; } t; t.f = x; t.u = bswap_32(t.u); return t.f; } int main() { unsigned x = 0xbeffbd7f; volatile float f = PA_FLOAT32_SWAP(*(float *)&x); printf("%08x %08x %08x %f\n", 0xbeffbd7f, *(unsigned *)&f, bswap_32(*(unsigned *)&f), f); } // snip the problem goes away with optimization when no temporary floating point registers are used the proposed solution is to avoid passing swapped floating point data in a float; this is done with new functions PA_READ_FLOAT32RE() and PA_WRITE_FLOAT32RE() which use uint32_t to dereference a pointer and byte-swap the data, hence no temporary float variable is used also delete PA_FLOAT32_TO_LE()/_BE(), not used Signed-off-by: Peter Meerwald <pmeerw at pmeerw.net> Reported-by: Felipe Sateler <fsateler at debian.org> --- src/pulsecore/endianmacros.h | 23 ++++++++++++----------- src/pulsecore/mix.c | 11 ++++------- src/pulsecore/sample-util.c | 4 ++-- src/pulsecore/sconv-s16le.c | 22 ++++++++-------------- src/pulsecore/svolume_c.c | 4 ++-- src/tests/mix-test.c | 4 ++-- src/tests/resampler-test.c | 4 ++-- 7 files changed, 32 insertions(+), 40 deletions(-) diff --git a/src/pulsecore/endianmacros.h b/src/pulsecore/endianmacros.h index 4822fc4..2e73136 100644 --- a/src/pulsecore/endianmacros.h +++ b/src/pulsecore/endianmacros.h @@ -71,25 +71,32 @@ static inline void PA_WRITE24LE(uint8_t *p, uint32_t u) { p[0] = (uint8_t) u; } -static inline float PA_FLOAT32_SWAP(float x) { +static inline float PA_READ_FLOAT32RE(const void *p) { union { float f; uint32_t u; } t; - t.f = x; - t.u = PA_UINT32_SWAP(t.u); + t.u = PA_UINT32_SWAP(*(uint32_t *) p); return t.f; } +static inline void PA_WRITE_FLOAT32RE(void *p, float x) { + union { + float f; + uint32_t u; + } t; + + t.f = x; + *(uint32_t *) p = PA_UINT32_SWAP(t.u); +} + #define PA_MAYBE_INT16_SWAP(c,x) ((c) ? PA_INT16_SWAP(x) : (x)) #define PA_MAYBE_UINT16_SWAP(c,x) ((c) ? PA_UINT16_SWAP(x) : (x)) #define PA_MAYBE_INT32_SWAP(c,x) ((c) ? PA_INT32_SWAP(x) : (x)) #define PA_MAYBE_UINT32_SWAP(c,x) ((c) ? PA_UINT32_SWAP(x) : (x)) -#define PA_MAYBE_FLOAT32_SWAP(c,x) ((c) ? PA_FLOAT32_SWAP(x) : (x)) - #ifdef WORDS_BIGENDIAN #define PA_INT16_FROM_LE(x) PA_INT16_SWAP(x) #define PA_INT16_FROM_BE(x) ((int16_t)(x)) @@ -115,9 +122,6 @@ static inline float PA_FLOAT32_SWAP(float x) { #define PA_UINT32_TO_LE(x) PA_UINT32_SWAP(x) #define PA_UINT32_TO_BE(x) ((uint32_t)(x)) - #define PA_FLOAT32_TO_LE(x) PA_FLOAT32_SWAP(x) - #define PA_FLOAT32_TO_BE(x) ((float) (x)) - #define PA_READ24NE(x) PA_READ24BE(x) #define PA_WRITE24NE(x,y) PA_WRITE24BE((x),(y)) @@ -148,9 +152,6 @@ static inline float PA_FLOAT32_SWAP(float x) { #define PA_UINT32_TO_LE(x) ((uint32_t)(x)) #define PA_UINT32_TO_BE(x) PA_UINT32_SWAP(x) - #define PA_FLOAT32_TO_LE(x) ((float) (x)) - #define PA_FLOAT32_TO_BE(x) PA_FLOAT32_SWAP(x) - #define PA_READ24NE(x) PA_READ24LE(x) #define PA_WRITE24NE(x,y) PA_WRITE24LE((x),(y)) diff --git a/src/pulsecore/mix.c b/src/pulsecore/mix.c index 10567d6..03c71f0 100644 --- a/src/pulsecore/mix.c +++ b/src/pulsecore/mix.c @@ -576,17 +576,14 @@ static void pa_mix_float32re_c(pa_mix_info streams[], unsigned nstreams, unsigne for (i = 0; i < nstreams; i++) { pa_mix_info *m = streams + i; - float v, cv = m->linear[channel].f; + float cv = m->linear[channel].f; - if (PA_LIKELY(cv > 0)) { - v = PA_FLOAT32_SWAP(*(float*) m->ptr); - v *= cv; - sum += v; - } + if (PA_LIKELY(cv > 0)) + sum += PA_READ_FLOAT32RE(m->ptr) * cv; m->ptr = (uint8_t*) m->ptr + sizeof(float); } - *data = PA_FLOAT32_SWAP(sum); + PA_WRITE_FLOAT32RE(data, sum); if (PA_UNLIKELY(++channel >= channels)) channel = 0; diff --git a/src/pulsecore/sample-util.c b/src/pulsecore/sample-util.c index dc5c1fd..539f3b8 100644 --- a/src/pulsecore/sample-util.c +++ b/src/pulsecore/sample-util.c @@ -296,9 +296,9 @@ void pa_sample_clamp(pa_sample_format_t format, void *dst, size_t dstr, const vo for (; n > 0; n--) { float f; - f = PA_FLOAT32_SWAP(*s); + f = PA_READ_FLOAT32RE(s); f = PA_CLAMP_UNLIKELY(f, -1.0f, 1.0f); - *d = PA_FLOAT32_SWAP(f); + PA_WRITE_FLOAT32RE(d, f); s = (const float*) ((const uint8_t*) s + sstr); d = (float*) ((uint8_t*) d + dstr); diff --git a/src/pulsecore/sconv-s16le.c b/src/pulsecore/sconv-s16le.c index 45cf972..0c1d16c 100644 --- a/src/pulsecore/sconv-s16le.c +++ b/src/pulsecore/sconv-s16le.c @@ -157,8 +157,7 @@ void pa_sconv_s16le_to_float32re(unsigned n, const int16_t *a, float *b) { for (; n > 0; n--) { int16_t s = *(a++); float k = INT16_FROM(s) * (1.0f / (1 << 15)); - k = PA_FLOAT32_SWAP(k); - *(b++) = k; + PA_WRITE_FLOAT32RE(b++, k); } } @@ -169,8 +168,7 @@ void pa_sconv_s32le_to_float32re(unsigned n, const int32_t *a, float *b) { for (; n > 0; n--) { int32_t s = *(a++); float k = INT32_FROM(s) * (1.0f / (1U << 31)); - k = PA_FLOAT32_SWAP(k); - *(b++) = k; + PA_WRITE_FLOAT32RE(b++, k); } } @@ -180,8 +178,7 @@ void pa_sconv_s16le_from_float32re(unsigned n, const float *a, int16_t *b) { for (; n > 0; n--) { int16_t s; - float v = *(a++); - v = PA_FLOAT32_SWAP(v) * (1 << 15); + float v = PA_READ_FLOAT32RE(a++) * (1 << 15); s = (int16_t) PA_CLAMP_UNLIKELY(lrintf(v), -0x8000, 0x7FFF); *(b++) = INT16_TO(s); } @@ -193,8 +190,7 @@ void pa_sconv_s32le_from_float32re(unsigned n, const float *a, int32_t *b) { for (; n > 0; n--) { int32_t s; - float v = *(a++); - v = PA_FLOAT32_SWAP(v) * (1U << 31); + float v = PA_READ_FLOAT32RE(a++) * (1U << 31); s = (int32_t) PA_CLAMP_UNLIKELY(llrintf(v), -0x80000000LL, 0x7FFFFFFFLL); *(b++) = INT32_TO(s); } @@ -325,7 +321,7 @@ void pa_sconv_s24le_to_float32re(unsigned n, const uint8_t *a, float *b) { for (; n > 0; n--) { int32_t s = READ24(a) << 8; float k = s * (1.0f / (1U << 31)); - *b = PA_FLOAT32_SWAP(k); + PA_WRITE_FLOAT32RE(b, k); a += 3; b++; } @@ -337,8 +333,7 @@ void pa_sconv_s24le_from_float32re(unsigned n, const float *a, uint8_t *b) { for (; n > 0; n--) { int32_t s; - float v = *a; - v = PA_FLOAT32_SWAP(v) * (1U << 31); + float v = PA_READ_FLOAT32RE(a) * (1U << 31); s = (int32_t) PA_CLAMP_UNLIKELY(llrint(v), -0x80000000LL, 0x7FFFFFFFLL); WRITE24(b, ((uint32_t) s) >> 8); a++; @@ -411,7 +406,7 @@ void pa_sconv_s24_32le_to_float32re(unsigned n, const uint32_t *a, float *b) { for (; n > 0; n--) { int32_t s = (int32_t) (UINT32_FROM(*a) << 8); float k = s * (1.0f / (1U << 31)); - *b = PA_FLOAT32_SWAP(k); + PA_WRITE_FLOAT32RE(b, k); a++; b++; } @@ -437,8 +432,7 @@ void pa_sconv_s24_32le_from_float32re(unsigned n, const float *a, uint32_t *b) { for (; n > 0; n--) { int32_t s; - float v = *a; - v = PA_FLOAT32_SWAP(v) * (1U << 31); + float v = PA_READ_FLOAT32RE(a) * (1U << 31); s = (int32_t) PA_CLAMP_UNLIKELY(llrint(v), -0x80000000LL, 0x7FFFFFFFLL); *b = UINT32_TO(((uint32_t) s) >> 8); a++; diff --git a/src/pulsecore/svolume_c.c b/src/pulsecore/svolume_c.c index ad2df18..2e2db12 100644 --- a/src/pulsecore/svolume_c.c +++ b/src/pulsecore/svolume_c.c @@ -125,9 +125,9 @@ static void pa_volume_float32re_c(float *samples, const float *volumes, unsigned for (channel = 0; length; length--) { float t; - t = PA_FLOAT32_SWAP(*samples); + t = PA_READ_FLOAT32RE(samples); t *= volumes[channel]; - *samples++ = PA_FLOAT32_SWAP(t); + PA_WRITE_FLOAT32RE(samples++, t); if (PA_UNLIKELY(++channel >= channels)) channel = 0; diff --git a/src/tests/mix-test.c b/src/tests/mix-test.c index d5bae13..e95607d 100644 --- a/src/tests/mix-test.c +++ b/src/tests/mix-test.c @@ -150,7 +150,7 @@ static void compare_block(const pa_sample_spec *ss, const pa_memchunk *chunk, in float *u = d; for (i = 0; i < chunk->length / pa_frame_size(ss); i++) { - float uu = PA_MAYBE_FLOAT32_SWAP(ss->format != PA_SAMPLE_FLOAT32NE, *u); + float uu = ss->format == PA_SAMPLE_FLOAT32NE ? *u : PA_READ_FLOAT32RE(u); fail_unless(fabsf(uu - *v) <= 1e-6f, NULL); ++u; ++v; @@ -264,7 +264,7 @@ static pa_memblock* generate_block(pa_mempool *pool, const pa_sample_spec *ss) { if (ss->format == PA_SAMPLE_FLOAT32RE) { float *u = d; for (i = 0; i < 10; i++) - u[i] = PA_FLOAT32_SWAP(float32ne_result[0][i]); + PA_WRITE_FLOAT32RE(&u[i], float32ne_result[0][i]); } else memcpy(d, float32ne_result[0], sizeof(float32ne_result[0])); diff --git a/src/tests/resampler-test.c b/src/tests/resampler-test.c index 60345af..f547770 100644 --- a/src/tests/resampler-test.c +++ b/src/tests/resampler-test.c @@ -98,7 +98,7 @@ static void dump_block(const char *label, const pa_sample_spec *ss, const pa_mem float *u = d; for (i = 0; i < chunk->length / pa_frame_size(ss); i++) { - printf("%4.3g ", ss->format == PA_SAMPLE_FLOAT32NE ? *u : PA_FLOAT32_SWAP(*u)); + printf("%4.3g ", ss->format == PA_SAMPLE_FLOAT32NE ? *u : PA_READ_FLOAT32RE(u)); u++; } @@ -222,7 +222,7 @@ static pa_memblock* generate_block(pa_mempool *pool, const pa_sample_spec *ss) { if (ss->format == PA_SAMPLE_FLOAT32RE) for (i = 0; i < 10; i++) - u[i] = PA_FLOAT32_SWAP(u[i]); + PA_WRITE_FLOAT32RE(&u[i], u[i]); break; } -- 1.9.1
