From 3f9d4224d8db7868b6c2f526746d597785d30c61 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Mon, 6 May 2024 17:13:23 -0400 Subject: printf decimal integer formatting: shave off one division once the remaining value is less than 10, the modulo operation to produce the final digit and division to prepare for next loop iteration can be dropped. this may be a meaningful performance distinction when formatting low-magnitude numbers in bulk, and should never hurt. based on patch by Viktor Reznov. --- src/stdio/vfprintf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c index dc648e7e..360d723a 100644 --- a/src/stdio/vfprintf.c +++ b/src/stdio/vfprintf.c @@ -166,7 +166,8 @@ static char *fmt_u(uintmax_t x, char *s) { unsigned long y; for ( ; x>ULONG_MAX; x/=10) *--s = '0' + x%10; - for (y=x; y; y/=10) *--s = '0' + y%10; + for (y=x; y>=10; y/=10) *--s = '0' + y%10; + if (y) *--s = '0' + y; return s; } -- cgit 1.4.1