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| author | Stuart Menefy <stuart.menefy@st.com> | 2010-11-11 18:26:31 +0000 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2011-02-15 16:24:05 +0900 |
| commit | a086536858ad0eb51c58074af2fc2c89ba9c1f5e (patch) | |
| tree | b15d3f63217842dd6d89d85dd2b8b216a82a3a5f /arch | |
| parent | 795abaf1e4e188c4171e3cd3dbb11a9fcacaf505 (diff) | |
| download | linux-a086536858ad0eb51c58074af2fc2c89ba9c1f5e.tar.gz linux-a086536858ad0eb51c58074af2fc2c89ba9c1f5e.tar.bz2 linux-a086536858ad0eb51c58074af2fc2c89ba9c1f5e.zip | |
sh: Ensure ST40-300 BogoMIPS value is consistent
A strange variation was seen in the BogoMIPS figure for the ST40-300.
This was eventually tracked down to sensitivity to the alignment of
the loop. So add an align directive to ensure this doesn't occur.
Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/sh/lib/delay.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/sh/lib/delay.c b/arch/sh/lib/delay.c index faa8f86c0db4..0901b2f14e15 100644 --- a/arch/sh/lib/delay.c +++ b/arch/sh/lib/delay.c @@ -10,6 +10,16 @@ void __delay(unsigned long loops) { __asm__ __volatile__( + /* + * ST40-300 appears to have an issue with this code, + * normally taking two cycles each loop, as with all + * other SH variants. If however the branch and the + * delay slot straddle an 8 byte boundary, this increases + * to 3 cycles. + * This align directive ensures this doesn't occur. + */ + ".balign 8\n\t" + "tst %0, %0\n\t" "1:\t" "bf/s 1b\n\t" |