Index: webrtc/common_audio/signal_processing/include/spl_inl.h |
diff --git a/webrtc/common_audio/signal_processing/include/spl_inl.h b/webrtc/common_audio/signal_processing/include/spl_inl.h |
index 3c0a81cf34a7e5fba062801936d5d2a31adfd922..90098caaaa2596b5d1e3ba22fa6e99e9c03f2675 100644 |
--- a/webrtc/common_audio/signal_processing/include/spl_inl.h |
+++ b/webrtc/common_audio/signal_processing/include/spl_inl.h |
@@ -15,6 +15,54 @@ |
#ifndef WEBRTC_SPL_SPL_INL_H_ |
#define WEBRTC_SPL_SPL_INL_H_ |
+#include "webrtc/system_wrappers/include/compile_assert_c.h" |
+ |
+extern const int8_t kWebRtcSpl_CountLeadingZeros32_Table[64]; |
+ |
+// Don't call this directly except in tests! |
+static __inline int WebRtcSpl_CountLeadingZeros32_NotBuiltin(uint32_t n) { |
+ // Normalize n by rounding up to the nearest number that is a sequence of 0 |
+ // bits followed by a sequence of 1 bits. This number has the same number of |
+ // leading zeros as the original n. There are exactly 33 such values. |
+ n |= n >> 1; |
+ n |= n >> 2; |
+ n |= n >> 4; |
+ n |= n >> 8; |
+ n |= n >> 16; |
+ |
+ // Multiply the modified n with a constant selected (by exhaustive search) |
+ // such that each of the 33 possible values of n give a product whose 6 most |
+ // significant bits are unique. Then look up the answer in the table. |
+ return kWebRtcSpl_CountLeadingZeros32_Table[(n * 0x8c0b2891) >> 26]; |
+} |
+ |
+// Don't call this directly except in tests! |
+static __inline int WebRtcSpl_CountLeadingZeros64_NotBuiltin(uint64_t n) { |
+ const int leading_zeros = n >> 32 == 0 ? 32 : 0; |
+ return leading_zeros + WebRtcSpl_CountLeadingZeros32_NotBuiltin( |
+ (uint32_t)(n >> (32 - leading_zeros))); |
+} |
+ |
+// Returns the number of leading zero bits in the argument. |
+static __inline int WebRtcSpl_CountLeadingZeros32(uint32_t n) { |
+#ifdef __GNUC__ |
+ COMPILE_ASSERT(sizeof(unsigned int) == sizeof(uint32_t)); |
+ return n == 0 ? 32 : __builtin_clz(n); |
+#else |
+ return WebRtcSpl_CountLeadingZeros32_NotBuiltin(n); |
+#endif |
+} |
+ |
+// Returns the number of leading zero bits in the argument. |
+static __inline int WebRtcSpl_CountLeadingZeros64(uint64_t n) { |
+#ifdef __GNUC__ |
+ COMPILE_ASSERT(sizeof(unsigned long long) == sizeof(uint64_t)); |
+ return n == 0 ? 64 : __builtin_clzll(n); |
+#else |
+ return WebRtcSpl_CountLeadingZeros64_NotBuiltin(n); |
+#endif |
+} |
+ |
#ifdef WEBRTC_ARCH_ARM_V7 |
#include "webrtc/common_audio/signal_processing/include/spl_inl_armv7.h" |
#else |
@@ -74,83 +122,26 @@ static __inline int16_t WebRtcSpl_SubSatW16(int16_t var1, int16_t var2) { |
#if !defined(MIPS32_LE) |
static __inline int16_t WebRtcSpl_GetSizeInBits(uint32_t n) { |
- int16_t bits; |
- |
- if (0xFFFF0000 & n) { |
- bits = 16; |
- } else { |
- bits = 0; |
- } |
- if (0x0000FF00 & (n >> bits)) bits += 8; |
- if (0x000000F0 & (n >> bits)) bits += 4; |
- if (0x0000000C & (n >> bits)) bits += 2; |
- if (0x00000002 & (n >> bits)) bits += 1; |
- if (0x00000001 & (n >> bits)) bits += 1; |
- |
- return bits; |
+ return 32 - WebRtcSpl_CountLeadingZeros32(n); |
} |
+// Return the number of steps a can be left-shifted without overflow, |
+// or 0 if a == 0. |
static __inline int16_t WebRtcSpl_NormW32(int32_t a) { |
- int16_t zeros; |
- |
- if (a == 0) { |
- return 0; |
- } |
- else if (a < 0) { |
- a = ~a; |
- } |
- |
- if (!(0xFFFF8000 & a)) { |
- zeros = 16; |
- } else { |
- zeros = 0; |
- } |
- if (!(0xFF800000 & (a << zeros))) zeros += 8; |
- if (!(0xF8000000 & (a << zeros))) zeros += 4; |
- if (!(0xE0000000 & (a << zeros))) zeros += 2; |
- if (!(0xC0000000 & (a << zeros))) zeros += 1; |
- |
- return zeros; |
+ return a == 0 ? 0 : WebRtcSpl_CountLeadingZeros32(a < 0 ? ~a : a) - 1; |
} |
+// Return the number of steps a can be left-shifted without overflow, |
+// or 0 if a == 0. |
static __inline int16_t WebRtcSpl_NormU32(uint32_t a) { |
- int16_t zeros; |
- |
- if (a == 0) return 0; |
- |
- if (!(0xFFFF0000 & a)) { |
- zeros = 16; |
- } else { |
- zeros = 0; |
- } |
- if (!(0xFF000000 & (a << zeros))) zeros += 8; |
- if (!(0xF0000000 & (a << zeros))) zeros += 4; |
- if (!(0xC0000000 & (a << zeros))) zeros += 2; |
- if (!(0x80000000 & (a << zeros))) zeros += 1; |
- |
- return zeros; |
+ return a == 0 ? 0 : WebRtcSpl_CountLeadingZeros32(a); |
} |
+// Return the number of steps a can be left-shifted without overflow, |
+// or 0 if a == 0. |
static __inline int16_t WebRtcSpl_NormW16(int16_t a) { |
- int16_t zeros; |
- |
- if (a == 0) { |
- return 0; |
- } |
- else if (a < 0) { |
- a = ~a; |
- } |
- |
- if (!(0xFF80 & a)) { |
- zeros = 8; |
- } else { |
- zeros = 0; |
- } |
- if (!(0xF800 & (a << zeros))) zeros += 4; |
- if (!(0xE000 & (a << zeros))) zeros += 2; |
- if (!(0xC000 & (a << zeros))) zeros += 1; |
- |
- return zeros; |
+ const int32_t a32 = a; |
+ return a == 0 ? 0 : WebRtcSpl_CountLeadingZeros32(a < 0 ? ~a32 : a32) - 17; |
} |
static __inline int32_t WebRtc_MulAccumW16(int16_t a, int16_t b, int32_t c) { |