[PATCH] make "fast unlzma" code much smaller

[Denis Vlasenko]

On Thursday 09 March 2006 19:35, Rob Landley wrote:
> On Thursday 09 March 2006 4:34 am, Denis Vlasenko wrote:
> > This patch improves inlining decisions in
> > archival/libunarchive/rangecoder.h so that:
> >
> > "fast unlzma" code is ~45% smaller with ~2% speed loss
> > "small unlzma" code is 17% faster with 10% size increase
> 
> #1 is good, #2 is bad.  Is there any way to have #1 without #2?

Yes:  http://195.66.192.167/linux/bbox/unlzma_size_v2.patch

These two patches (v1 and v2) differ only in having
"always_inline" for v1 and "speed_inline" for v2 here:


 /* Called ~10 times, but very small, thus inlined */
 static speed_inline void rc_update_bit_0(rc_t * rc, uint16_t * p)
 {
 	rc->range = rc->bound;
 	*p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
 }
 static speed_inline void rc_update_bit_1(rc_t * rc, uint16_t * p)
 {
 	rc->range -= rc->bound;


Thus "small unlzma" v1 is faster and v2 is smaller.
"fast unlzma" is identical for v1 and v2.
--
vda