I was considering whether "const void *p" should instead be a "const float *p" (in the function prototypes), but maybe not - a reversed float cannot be considered a float anymore, due to the NaN problems you describe below. OTOH, that leaves us with a few float pointers in the callers to these functions, which should perhaps be converted to void* too, but then you can't index them... So hey, it fixes a bug, and I assume you have run the relevant tests and they succeeded. So while it's slightly inconsistent to mix float* and void*, this one is acked too. On 2014-09-03 02:25, Peter Meerwald wrote: > From: Peter Meerwald <pmeerw at 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; > } > -- David Henningsson, Canonical Ltd. https://launchpad.net/~diwic
