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utils: use 128bits division on x86_64
This commit is contained in:
Wim Taymans
parent
4ad052fed7
commit
b0c1ebbd08
1 changed files with 43 additions and 52 deletions
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@ -258,19 +258,20 @@ gst_util_uint64_mul_uint64 (GstUInt64 * c1, GstUInt64 * c0, guint64 arg1,
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}
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#endif /* defined (__x86_64__) */
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/* count leading zeros */
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#if defined (__x86_64__) && defined (__GNUC__)
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static inline guint
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gst_util_clz (guint32 val)
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static inline guint64
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gst_util_div128_64 (GstUInt64 c1, GstUInt64 c0, guint64 denom)
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{
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guint s;
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guint64 res;
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__asm__ __volatile__ ("bsrl %0, %0 \n\t"
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"xor $31, %0 \n\t":"=r" (s):"0" (val)
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__asm__ __volatile__ ("divq %3":"=a" (res)
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:"d" (c1.ll), "a" (c0.ll), "g" (denom)
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);
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return s;
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return res;
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}
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#else /* defined (__x86_64__) */
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#else
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/* count leading zeros */
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static inline guint
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gst_util_clz (guint32 val)
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{
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@ -289,7 +290,6 @@ gst_util_clz (guint32 val)
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return s;
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}
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#endif /* defined (__x86_64__) */
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/* based on Hacker's Delight p152 */
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static inline guint64
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@ -349,48 +349,7 @@ gst_util_div128_64 (GstUInt64 c1, GstUInt64 c0, guint64 denom)
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return q0.ll;
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}
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/* multiply a 64-bit unsigned int by a 32-bit unsigned int into a 96-bit
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* unsigned int. the high 64 bits and low 32 bits of the product are
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* placed in c1 and c0 respectively. this operation cannot overflow. */
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#if defined (__x86_64__) && defined (__GNUC__)
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static inline void
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gst_util_uint64_mul_uint32 (GstUInt64 * c1, GstUInt64 * c0, guint64 arg1,
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guint32 arg2)
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{
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__asm__ __volatile__ ("mul %%rcx \n\t"
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"mov %%rax, %%rcx \n\t"
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"shl $32, %%rdx \n\t"
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"shr $32, %%rcx \n\t"
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"or %%rcx, %%rdx \n\t"
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"and $0xffffffff, %%eax \n\t":"=a" (c0->ll), "=d" (c1->ll)
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:"a" (arg1), "c" ((guint64) arg2)
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);
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}
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#else /* defined (__x86_64__) */
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static inline void
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gst_util_uint64_mul_uint32 (GstUInt64 * c1, GstUInt64 * c0, guint64 arg1,
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guint32 arg2)
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{
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GstUInt64 a;
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a.ll = arg1;
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c0->ll = (guint64) a.l.low * arg2;
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c1->ll = (guint64) a.l.high * arg2 + c0->l.high;
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c0->l.high = 0;
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}
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#endif /* defined (__x86_64__) */
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/* divide a 96-bit unsigned int by a 32-bit unsigned int when we know the
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* quotient fits into 64 bits. the high 64 bits and low 32 bits of the
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* numerator are expected in c1 and c0 respectively. */
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static inline guint64
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gst_util_div96_32 (guint64 c1, guint64 c0, guint32 denom)
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{
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c0 += (c1 % denom) << 32;
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return ((c1 / denom) << 32) + (c0 / denom);
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}
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#endif /* defined (__GNUC__) */
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/* add correction with carry */
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#define CORRECT(c0,c1,val) \
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@ -424,6 +383,30 @@ gst_util_uint64_scale_uint64_unchecked (guint64 val, guint64 num,
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return gst_util_div128_64 (c1, c0, denom);
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}
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#if !defined (__x86_64__)
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static inline void
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gst_util_uint64_mul_uint32 (GstUInt64 * c1, GstUInt64 * c0, guint64 arg1,
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guint32 arg2)
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{
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GstUInt64 a;
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a.ll = arg1;
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c0->ll = (guint64) a.l.low * arg2;
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c1->ll = (guint64) a.l.high * arg2 + c0->l.high;
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c0->l.high = 0;
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}
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/* divide a 96-bit unsigned int by a 32-bit unsigned int when we know the
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* quotient fits into 64 bits. the high 64 bits and low 32 bits of the
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* numerator are expected in c1 and c0 respectively. */
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static inline guint64
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gst_util_div96_32 (guint64 c1, guint64 c0, guint32 denom)
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{
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c0 += (c1 % denom) << 32;
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return ((c1 / denom) << 32) + (c0 / denom);
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}
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static inline guint64
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gst_util_uint64_scale_uint32_unchecked (guint64 val, guint32 num,
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guint32 denom, guint32 correct)
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@ -443,6 +426,7 @@ gst_util_uint64_scale_uint32_unchecked (guint64 val, guint32 num,
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/* compute quotient, fits in 64 bits */
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return gst_util_div96_32 (c1.ll, c0.ll, denom);
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}
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#endif
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/* the guts of the gst_util_uint64_scale() variants */
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static guint64
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@ -457,6 +441,8 @@ _gst_util_uint64_scale (guint64 val, guint64 num, guint64 denom,
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if (G_UNLIKELY (num == denom))
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return val;
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/* on 64bits we always use a full 128bits multipy/division */
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#if !defined (__x86_64__)
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/* denom is low --> try to use 96 bit muldiv */
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if (G_LIKELY (denom <= G_MAXUINT32)) {
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/* num is low --> use 96 bit muldiv */
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@ -469,6 +455,7 @@ _gst_util_uint64_scale (guint64 val, guint64 num, guint64 denom,
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return gst_util_uint64_scale_uint32_unchecked (num, (guint32) val,
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(guint32) denom, correct);
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}
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#endif /* !defined (__x86_64__) */
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/* val is high and num is high --> use 128-bit muldiv */
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return gst_util_uint64_scale_uint64_unchecked (val, num, denom, correct);
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@ -573,10 +560,14 @@ _gst_util_uint64_scale_int (guint64 val, gint num, gint denom, gint correct)
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return val / (guint64) denom;
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}
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#if !defined (__x86_64__)
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/* num and denom are not negative so casts are OK */
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return gst_util_uint64_scale_uint32_unchecked (val, (guint32) num,
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(guint32) denom, (guint32) correct);
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#else
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/* always use full 128bits scale */
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return gst_util_uint64_scale_uint64_unchecked (val, num, denom, correct);
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#endif
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}
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/**
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