6 Aug
2009
6 Aug
'09
12:07 p.m.
Dear Renato Andreola,
In message 4A7AA72C.8010704@imagos.it you wrote:
From be54cb97ca26bcbbc1a908d1f2a5447b6639dc59 Mon Sep 17 00:00:00 2001 From: Renato Andreola renato.andreola@imagos.it Date: Thu, 6 Aug 2009 11:40:52 +0200 Subject: [PATCH] drivers/mtd/cfi_flash: precision and underflow problem in tout calculation
With old configuration it could happen tout=0 if CONFIG_SYS_HZ<1000 solved using an unsigned long long
I don't like this implementation - using LL divisions just pulls in more dependencies on libgcc code and the like, and blows up the code size.
-#if CONFIG_SYS_HZ != 1000
- tout *= CONFIG_SYS_HZ/1000;
+#if CONFIG_SYS_HZ != 1000
- unsigned long long ull;
- ull = tout*CONFIG_SYS_HZ + CONFIG_SYS_HZ/2;
- tout = ull/1000; /* Compute: tout *= CONFIG_SYS_HZ/1000; */
I think rounding up should be sufficient here, i. e. something like:
tout *= DIV_ROUND_UP(CONFIG_SYS_HZ,1000);
?
Best regards,
Wolfgang Denk
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