Hi, Thanks for the insightful comments. Here are my responses:
* Why don't I implement the divider in C? It is not because I think it's performance critical (I haven't benchmarked it yet), but because I have a probably wrong impression that the divider has to be written in assembly --- all dividers in arch/arm/lib/ are written in ARM assembly. What is the policy here for using assembly or C? * When do we need a 64-bit divider? In kernel code do_div() is used for various purposes. So I think it should be quite often that we would need a 64-bit divider in U-Boot. * Do we need a 64-64 bit divider? do_div() defines 64-32 bit division semantics (dividend is 64-bit and divisor is 32-bit), and this patch implements a 64-64 bit divider (both dividend and divisor are 64-bit). I have to admit that I can't think of scenarios or reasons to justify a 64-64 bit divider instead of a 64-32 bit divider, except that a 64-64 bit divider is more generic than a 64-32 bit one. So I guess we can agree that a 64-bit divider is feature that is nice to have, and we should decide: * Do we need a 64-64 bit divider or a 64-32 bit one? * Do we write it in C or assembly? Depending on our decisions, I will rewrite (or abandon) this patch accordingly. Regards, Che-Liang On Thu, Sep 1, 2011 at 4:03 AM, Wolfgang Denk <w...@denx.de> wrote: > Dear Che-Liang Chiou, > > In message <1314787130-1043-1-git-send-email-clch...@chromium.org> you wrote: >> This patch adds a 64-64 bit divider that supports ARMv4 and above. > > To summarize the misc feedback: Please explain in detail which > problem you are trying to fix. We see no need for this patch so far. > > Best regards, > > Wolfgang Denk > > -- > DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany > Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de > "Success covers a multitude of blunders." - George Bernard Shaw > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot