Module: xenomai-head
Branch: master
Commit: 3c17098157e16830d101411508310dd326214deb
URL:
http://git.xenomai.org/?p=xenomai-head.git;a=commit;h=3c17098157e16830d101411508310dd326214deb
Author: Gilles Chanteperdrix <gilles.chanteperd...@xenomai.org>
Date: Mon Dec 21 23:45:03 2009 +0100
arith: avoid ARM Linux do_div compile-time optimizations.
They are not critical for xnarch_init_u32frac and xnarch_init_llmulshft,
and they cause the compiler register allocation to fail.
---
include/asm-generic/arith.h | 14 +++++++++++---
1 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/include/asm-generic/arith.h b/include/asm-generic/arith.h
index dac9ccb..416e742 100644
--- a/include/asm-generic/arith.h
+++ b/include/asm-generic/arith.h
@@ -275,9 +275,13 @@ static inline void xnarch_init_u32frac(rthal_u32frac_t
*const f,
const unsigned m,
const unsigned d)
{
+ /* Avoid clever compiler optimizations to occur when d is
+ known at compile-time. The performance of this function is
+ not critical since it is only called at init time. */
+ volatile unsigned vol_d = d;
f->integ = m / d;
- f->frac = __rthal_generic_div96by32(__rthal_u64fromu32(m % d, 0),
- 0, d, NULL);
+ f->frac = __rthal_generic_div96by32
+ (__rthal_u64fromu32(m % d, 0), 0, vol_d, NULL);
}
#ifndef rthal_nodiv_imuldiv
@@ -354,12 +358,16 @@ static inline void xnarch_init_llmulshft(const unsigned
m_in,
unsigned *m_out,
unsigned *s_out)
{
+ /* Avoid clever compiler optimizations to occur when d is
+ known at compile-time. The performance of this function is
+ not critical since it is only called at init time. */
+ volatile unsigned vol_d = d_in;
unsigned long long mult;
*s_out = 31;
while (1) {
mult = ((unsigned long long)m_in) << *s_out;
- do_div(mult, d_in);
+ do_div(mult, vol_d);
if (mult <= 0x7FFFFFFF)
break;
(*s_out)--;
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