Messages in this thread | | | From | Denis Vlasenko <> | Subject | Re: How can I link the kernel with libgcc ? | Date | Fri, 10 Mar 2006 12:37:35 +0200 |
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On Friday 10 March 2006 05:47, Carlos Munoz wrote: > Lee Revell wrote: > > >On Thu, 2006-03-09 at 19:25 -0800, Carlos Munoz wrote: > > > > > >>I figured out how to get the driver to use floating point operations. > >>I included source code (from an open source math library) for the > >>log10 function in the driver. Then I added the following lines to the > >>file arch/sh/kernel/sh_ksyms.c: > >> > >> > > > >Where is the source code to your driver? > > > >Lee > > > > > > > Hi Lee, > > Be warned. This driver is in the early stages of development. There is > still a lot of work that needs to be done (interrupt, dma, etc, etc).
What? You are using log10 only twice!
if (!(siu_obj_status & ST_OPEN)) { ... /* = log2(over) */ ydef[22] = (u_int32_t)(log10((double)(over & 0x0000003f)) / log10(2)); ... } else { ... if (coef) { ydef[16] = 0x03045000 | (over << 26) | (tap - 4); ydef[17] = (tap * 2 + 1); /* = log2(over) */ ydef[22] = (u_int32_t) (log10((double)(over & 0x0000003f)) / log10(2)); }
Don't you think that log10((double)(over & 0x0000003f)) / log10(2) can have only 64 different values depending on the result of (over & 0x3f)?
Obtain them from precomputed uint32_t log10table[64]. -- vda - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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