diff options
Diffstat (limited to 'src/liblzma')
| -rw-r--r-- | src/liblzma/lzma/lzma_decoder.c | 9 | ||||
| -rw-r--r-- | src/liblzma/rangecoder/range_decoder.h | 11 |
2 files changed, 18 insertions, 2 deletions
diff --git a/src/liblzma/lzma/lzma_decoder.c b/src/liblzma/lzma/lzma_decoder.c index 6c9cbe22..58045e11 100644 --- a/src/liblzma/lzma/lzma_decoder.c +++ b/src/liblzma/lzma/lzma_decoder.c @@ -474,6 +474,15 @@ lzma_decode(void *coder_ptr, lzma_dict *restrict dictptr, // Variable number (1-5) of bits // from a reverse bittree. This // isn't worth manual unrolling. + // + // NOTE: Making one or many of the + // variables (probs, symbol, offset, + // or limit) local here (instead of + // using those declared outside the + // main loop) can affect code size + // and performance which isn't a + // surprise but it's not so clear + // what is the best. do { rc_bit_add_if_1(probs, rep0, offset); diff --git a/src/liblzma/rangecoder/range_decoder.h b/src/liblzma/rangecoder/range_decoder.h index ffec7bf2..ddac1060 100644 --- a/src/liblzma/rangecoder/range_decoder.h +++ b/src/liblzma/rangecoder/range_decoder.h @@ -305,8 +305,15 @@ do { \ } while (0) -// Decode one bit from variable-sized reverse bittree. -// The loop is done in the code that uses this macro. +// Decode one bit from variable-sized reverse bittree. The loop is done +// in the code that uses this macro. This could be changed if the assembly +// version benefited from having the loop done in assembly but it didn't +// seem so in early 2024. +// +// Also, if the loop was done here, the loop counter would likely be local +// to the macro so that it wouldn't modify yet another input variable. +// If a _safe version of a macro with a loop was done then a modifiable +// input variable couldn't be avoided though. #define rc_bit_add_if_1(probs, dest, value_to_add_if_1) \ rc_bit(probs[symbol], \ , \ |