Re: TARGET_FPU not getting populated for powerpc 405/440 fpu-hard targets

Elvis Dowson

Hi Khem,

On Aug 24, 2012, at 8:35 PM, Khem Raj wrote:

On Fri, Aug 24, 2012 at 9:27 AM, Elvis Dowson <elvis.dowson@...> wrote:
I just observed that TARGET_FPU is not getting populated, when you do
a build for fpu-hard targets. For fpu-soft targets, it displays TARGET_FPU =
"soft", but for fpu-hard targets, it display TARGET_FPU = "".

that means default is hard for this architecture. This option is
essentially used to configure gcc
unless your fpu is special like fsl one's you are good here.

The FPU unit is an IP core, that is attached to a generic PowerPC405 or PowerPC440 embedded processor core on the FPGA, which by default doesn't contain an FPU unit. 

In the Xilinx FPGA hardware project, I have to add this FPU unit, and there are some additional options that I can see relevant to this setup with the FPU unit, such as -mxilinx-fpu and -mfpu=dp_full

Should I specify them in TUNE_CCARGS (as shown below) or TUNE_FEATURES_tune-ppc405e (not done below) or specify the same values for both variables ?

TUNE_CCARGS += "${@bb.utils.contains("TUNE_FEATURES", "ppc405e", "-mcpu=405fp -mxilinx-fpu -mfpu=dp_full", "", d)}"

AVAILTUNES += "ppc405e"
TUNE_FEATURES_tune-ppc405e = "m32 ppc405e fpu-hard"

Best regards,

Elvis Dowson

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