Denis Vlasenko wrote:
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
Hi Denis,
Yes, the driver code so far only uses log10 twice, but there will be
more uses for it as I populate the rest of the tables. However, I think
its use will be some what limited. I wasn't aware that the floating
point registers are not saved. I'll investigate a way to create a table
with pre-calculated log10 values.
Thanks,
Carlos
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