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Sergei Organov wrote:
The patch below boosts performance of decimal formatting of
integers by
roughly a factor of 2 on ARM7 CPU without hardware integer
division. In
fact it replaces integer modulo operation with multiply and
subtract,
that hopefully is either faster or roughly the same on all supported
CPUs.
I agree. I've applied the patch, thanks!
I think this patch could need a comment in the code, which explains why there's
not simply a modulo.
Good idea. I've added this:
Index: src/output/vfnprintf.cxx
===================================================================
RCS file:
/cvs/ecos/ecos/packages/language/c/libc/stdio/current/src/output/vfnprintf.cxx,v
retrieving revision 1.9
diff -u -5 -p -r1.9 vfnprintf.cxx
--- src/output/vfnprintf.cxx 22 Dec 2006 21:37:00 -0000 1.9
+++ src/output/vfnprintf.cxx 2 Jan 2007 11:53:12 -0000
@@ -553,10 +553,11 @@ number: if ((dprec = pre
break;
case DEC:
/* many numbers are 1 digit */
while (_uquad >= 10) {
+ /* The following is
usually faster than using a modulo */
u_quad_t next = _uquad / 10;
*--cp = to_char(_uquad -
(next * 10));
_uquad = next;
}
*--cp = to_char(_uquad);
Jifl
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