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374f7c0334
Replaces flac_lpc_32_c, the wide predictor path every 24-bit stream takes, and 16-bit streams encoded at high coefficient precision. The coefficients are invariant for the whole call, but the C loop reloaded all of them for every output sample and spilled its loop bound to the stack on top of that. Orders 1-8 now keep every coefficient in a register; orders 10 and 12, which is what -8 emits, get their own unrolled loops instead of the generic chunked one. An ARMv5E kernel using the packed 16-bit multiplies is included behind FLAC_LPC32_NARROW_ASM, off by default: it needs bps <= 16, and only about half the subframes of such a stream can use it. Measured with test_codec on 24-bit/96kHz streams. At predictor order 12: 36.24 MHz on e200 (ARMv4) against 62.29 MHz before. The same file improves from 37.65 MHz to 27.3 MHz on Clip+ (ARMv5). Bit-exact against flac -d over four complete streams on both targets, with and without the assembly, and the kernels are checked against an int64_t reference across every order 1-32, qlevel 0-15 and coefficient precision 1-15. The rarely-executed orders stay in DRAM: the codec's IRAM window on PP502x is nearly full and demoting them measured no cost, leaving 96 bytes free. FLAC_LPC32_NO_IRAM demotes the whole filter. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Change-Id: Icd8bd298973b9f5c26c103af8adf47b03489d69f |
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| .. | ||
| codecs | ||
| dsp | ||
| metadata | ||
| test | ||
| platform.h | ||
| rbcodec.make | ||
| rbcodecconfig-example.h | ||
| rbcodecplatform-unix.h | ||
| SOURCES | ||