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vm: minor cleanup

db4
Slava Pestov 2009-11-08 06:08:17 -06:00
parent 5d79450d9d
commit 8b52d85aed
2 changed files with 25 additions and 35 deletions
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58
vm/bitwise_hacks.hpp
View File

@ -1,7 +1,29 @@
namespace factor namespace factor
{ {
/* These algorithms were snarfed from various places. I did not come up with them myself */ inline cell log2(cell x)
{
cell n;
#if defined(FACTOR_X86) || defined(FACTOR_AMD64)
asm ("bsr %1, %0;":"=r"(n):"r"(x));
#elif defined(FACTOR_PPC)
asm ("cntlzw %1, %0;":"=r"(n):"r"(x));
n = (31 - n);
#else
#error Unsupported CPU
#endif
return n;
}
inline cell rightmost_clear_bit(cell x)
{
return log2(~x & (x + 1));
}
inline cell rightmost_set_bit(cell x)
{
return log2(x & -x);
}
inline cell popcount(cell x) inline cell popcount(cell x)
{ {
@ -24,39 +46,7 @@ inline cell popcount(cell x)
x = (x + (x >> 4)) & k4 ; // put count of each 8 bits into those 8 bits x = (x + (x >> 4)) & k4 ; // put count of each 8 bits into those 8 bits
x = (x * kf) >> ks; // returns 8 most significant bits of x + (x<<8) + (x<<16) + (x<<24) + ... x = (x * kf) >> ks; // returns 8 most significant bits of x + (x<<8) + (x<<16) + (x<<24) + ...
return (cell)x; return x;
}
inline cell log2(cell x)
{
#if defined(FACTOR_X86)
cell n;
asm ("bsr %1, %0;":"=r"(n):"r"(x));
#elif defined(FACTOR_AMD64)
cell n;
asm ("bsr %1, %0;":"=r"(n):"r"(x));
#else
cell n = 0;
#ifdef FACTOR_64
if (x >= (cell)1 << 32) { x >>= 32; n += 32; }
#endif
if (x >= (cell)1 << 16) { x >>= 16; n += 16; }
if (x >= (cell)1 << 8) { x >>= 8; n += 8; }
if (x >= (cell)1 << 4) { x >>= 4; n += 4; }
if (x >= (cell)1 << 2) { x >>= 2; n += 2; }
if (x >= (cell)1 << 1) { n += 1; }
#endif
return n;
}
inline cell rightmost_clear_bit(cell x)
{
return log2(~x & (x + 1));
}
inline cell rightmost_set_bit(cell x)
{
return log2(x & -x);
} }
} }

2
vm/full_collector.cpp
View File

@ -126,7 +126,7 @@ void factor_vm::collect_full(bool trace_contexts_p)
{ {
collect_mark_impl(trace_contexts_p); collect_mark_impl(trace_contexts_p);
collect_sweep_impl(); collect_sweep_impl();
if(data->tenured->largest_free_block() <= data->nursery->size + data->aging->size) if(data->low_memory_p())
collect_compact_impl(trace_contexts_p); collect_compact_impl(trace_contexts_p);
else else
update_code_heap_words_and_literals(); update_code_heap_words_and_literals();