forked from len0rd/rockbox
Extend av_log2 in codeclib into a generic for scanning for set bits, which can provide either log2 or leading-zero-count output, and can force mapping 0 input to 0 output if needed (otherwise 0 input produces undefined result). Replace av_log2 in lib/codeclib.h, floor_log2 and wl_min_lzc in libfaad/common.c and common.h, and count_leading_zeros in libalac/alac.c with macros using bs_generic.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23903 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Andrew Mahone
parent
3683bb67db
commit
85aad9b397
6 changed files with 96 additions and 141 deletions
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@ -33,6 +33,15 @@ unsigned char* mp3buf; // The actual MP3 buffer from Rockbox
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unsigned char* mallocbuf; // 512K from the start of MP3 buffer
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unsigned char* filebuf; // The rest of the MP3 buffer
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unsigned bs_log2(unsigned x)
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{ return bs_generic(x, BS_LOG2); }
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unsigned bs_log2_0(unsigned x)
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{ return bs_generic(x, BS_LOG2|BS_0_0); }
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unsigned bs_clz(unsigned x)
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{ return bs_generic(x, BS_CLZ); }
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unsigned bs_clz_0(unsigned x)
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{ return bs_generic(x, BS_CLZ|BS_0_0); }
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int codec_init(void)
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{
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mem_ptr = 0;
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@ -139,7 +148,7 @@ void qsort(void *base, size_t nmemb, size_t size,
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}
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/* From ffmpeg - libavutil/common.h */
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const uint8_t ff_log2_tab[256] ICONST_ATTR = {
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const uint8_t bs_log2_tab[256] ICONST_ATTR = {
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0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,
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5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
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6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
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@ -150,6 +159,17 @@ const uint8_t ff_log2_tab[256] ICONST_ATTR = {
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7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
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};
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const uint8_t bs_clz_tab[256] ICONST_ATTR = {
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8,7,6,6,5,5,5,5,4,4,4,4,4,4,4,4,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,
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2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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};
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#ifdef RB_PROFILE
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void __cyg_profile_func_enter(void *this_fn, void *call_site) {
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#ifdef CPU_COLDFIRE
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@ -74,45 +74,80 @@ unsigned udiv32_arm(unsigned a, unsigned b);
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#define UDIV32(a, b) (a / b)
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#endif
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#if !defined(CPU_ARM) || ARM_ARCH < 5
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/* From libavutil/common.h */
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extern const uint8_t bs_log2_tab[256] ICONST_ATTR;
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extern const uint8_t bs_clz_tab[256] ICONST_ATTR;
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#endif
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#define BS_LOG2 0 /* default personality, equivalent floor(log2(x)) */
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#define BS_CLZ 1 /* alternate personality, Count Leading Zeros */
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#define BS_SHORT 2 /* input guaranteed not to exceed 16 bits */
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#define BS_0_0 4 /* guarantee mapping of 0 input to 0 output */
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/* Generic bit-scanning function, used to wrap platform CLZ instruction or
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scan-and-lookup code, and to provide control over output for 0 inputs. */
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static inline unsigned int bs_generic(unsigned int v, int mode)
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{
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#if defined(CPU_ARM) && ARM_ARCH >= 5
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unsigned int r = __builtin_clz(v);
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if (mode & BS_CLZ)
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{
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if (mode & BS_0_0)
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r &= 31;
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} else {
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r = 31 - r;
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/* If mode is constant, this is a single conditional instruction */
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if (mode & BS_0_0 && (signed)r < 0)
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r += 1;
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}
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#else
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const uint8_t *bs_tab;
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unsigned int r;
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unsigned int n = v;
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int inc;
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/* Set up table, increment, and initial result value based on
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personality. */
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if (mode & BS_CLZ)
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{
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bs_tab = bs_clz_tab;
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r = 24;
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inc = -16;
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} else {
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bs_tab = bs_log2_tab;
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r = 0;
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inc = 16;
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}
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if (!(mode & BS_SHORT) && n >= 0x10000) {
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n >>= 16;
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r += inc;
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}
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if (n > 0xff) {
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n >>= 8;
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r += inc / 2;
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}
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#ifdef CPU_COLDFIRE
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/* The high 24 bits of n are guaranteed empty after the above, so a
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superfluous ext.b instruction can be saved by loading the LUT value over
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n with asm */
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asm volatile (
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"move.b (%1,%0.l),%0"
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: "+d" (n)
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: "a" (bs_tab)
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);
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#else
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n = bs_tab[n];
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#endif
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r += n;
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if (mode & BS_CLZ && mode & BS_0_0 && v == 0)
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r = 0;
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#endif
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return r;
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}
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/* TODO figure out if we really need to care about calculating
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av_log2(0) */
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#if defined(CPU_ARM) && ARM_ARCH >= 6
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static inline unsigned int av_log2(uint32_t v)
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{
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unsigned int r;
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asm volatile("clz %[r], %[v]\n\t" /* count leading zeroes */
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"rsb %[r], %[r], #31\n\t" /* r = 31 - leading zeroes */
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"usat %[r], #5, %[r]\n\t" /* unsigned saturate r so -1 -> 0 */
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:[r] "=r" (r) : [v] "r" (v));
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return(r);
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}
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#elif defined(CPU_ARM) && ARM_ARCH >= 5
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static inline unsigned int av_log2(uint32_t v)
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{
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return v ? 31 - __builtin_clz(v) : 0;
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}
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#else /* CPU_ARM */
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/* From libavutil/common.h */
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extern const uint8_t ff_log2_tab[256] ICONST_ATTR;
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static inline unsigned int av_log2(unsigned int v)
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{
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int n;
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n = 0;
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if (v & 0xffff0000) {
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v >>= 16;
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n += 16;
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}
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if (v & 0xff00) {
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v >>= 8;
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n += 8;
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}
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n += ff_log2_tab[v];
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return n;
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}
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#endif
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#define av_log2(v) bs_generic(v, BS_0_0)
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/* Various codec helper functions */
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@ -166,46 +166,7 @@ static inline void unreadbits(alac_file *alac, int bits)
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alac->input_buffer_bitaccumulator *= -1;
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}
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/* ARMv5+ has a clz instruction equivalent to our function.
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*/
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#if (defined(CPU_ARM) && (ARM_ARCH > 4))
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static inline int count_leading_zeros(uint32_t v)
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{
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return __builtin_clz(v);
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}
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#else
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static const unsigned char bittab[16] ICONST_ATTR = {
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0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4
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};
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static inline int count_leading_zeros(int input)
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{
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int output = 32;
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#if 0
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/* Experimentation has shown that the following test is always false,
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so we don't bother to perform it. */
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if (input & 0xffff0000)
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{
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input >>= 16;
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output -= 16;
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}
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#endif
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if (input & 0xff00)
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{
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input >>= 8;
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output -= 8;
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}
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if (input & 0xf0)
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{
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input >>= 4;
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output -= 4;
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}
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output -= bittab[input];
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return output;
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}
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#endif
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#define count_leading_zeros(x) bs_generic(x, BS_CLZ|BS_SHORT)
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void basterdised_rice_decompress(alac_file *alac,
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int32_t *output_buffer,
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@ -241,58 +241,7 @@ uint32_t random_int(void)
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return (__r1 = (t3 >> 1) | t1 ) ^ (__r2 = (t4 + t4) | t2 );
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}
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uint32_t ones32(uint32_t x)
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{
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x -= ((x >> 1) & 0x55555555);
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x = (((x >> 2) & 0x33333333) + (x & 0x33333333));
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x = (((x >> 4) + x) & 0x0f0f0f0f);
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x += (x >> 8);
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x += (x >> 16);
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return (x & 0x0000003f);
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}
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uint32_t floor_log2(uint32_t x)
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{
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#if 1
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x |= (x >> 1);
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x |= (x >> 2);
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x |= (x >> 4);
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x |= (x >> 8);
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x |= (x >> 16);
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return (ones32(x) - 1);
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#else
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uint32_t count = 0;
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while (x >>= 1)
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count++;
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return count;
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#endif
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}
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/* returns position of first bit that is not 0 from msb,
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* starting count at lsb */
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uint32_t wl_min_lzc(uint32_t x)
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{
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#if 1
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x |= (x >> 1);
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x |= (x >> 2);
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x |= (x >> 4);
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x |= (x >> 8);
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x |= (x >> 16);
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return (ones32(x));
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#else
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uint32_t count = 0;
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while (x >>= 1)
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count++;
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return (count + 1);
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#endif
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}
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#define floor_log2(x) bs_generic(x, BS_LOG2)
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#ifdef FIXED_POINT
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@ -399,9 +399,7 @@ typedef real_t complex_t[2];
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/* common functions */
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uint8_t cpu_has_sse(void);
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uint32_t random_int(void);
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uint32_t ones32(uint32_t x);
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uint32_t floor_log2(uint32_t x);
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uint32_t wl_min_lzc(uint32_t x);
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#define wl_min_lzc(x) bs_generic(x, BS_LOG2|BS_0_0)
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#ifdef FIXED_POINT
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#define LOG2_MIN_INF REAL_CONST(-10000)
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int32_t log2_int(uint32_t val);
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@ -222,10 +222,6 @@ static void auto_correlation(sbr_info *sbr, acorr_coef *ac,
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exp = wl_min_lzc(mask);
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/* improves accuracy */
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if (exp > 0)
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exp -= 1;
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for (j = offset; j < len + offset; j++)
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{
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real_t buf_j = ((QMF_RE(buffer[j][bd])+(1<<(exp-1)))>>exp);
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@ -293,10 +289,6 @@ static void auto_correlation(sbr_info *sbr, acorr_coef *ac, qmf_t buffer[MAX_NTS
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exp = wl_min_lzc(mask);
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/* improves accuracy */
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if (exp > 0)
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exp -= 1;
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pow2_to_exp = 1<<(exp-1);
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temp2_r = (QMF_RE(buffer[offset-2][bd]) + pow2_to_exp) >> exp;
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