[arm-gnu] undefined reference to _init

[Brad Badke]

Let's try this again, had a cut/paste error.

CFLAGS=-mcpu=cortex-a8
CFLAGS+=-mfpu=neon
CFLAG+=-mfpu=vfpv3-d16
CFLAGS+=-c ${${TARGET_MODE}_FLAG} -mlong-calls -fdata-sections -funsigned-char -ffunction-sections -Wall ${IPATH} -Dgcc ${DEVICE_D} ${EVM_D} -D SUPPORT_UNALIGNED
CFLAGS+=-nostartfiles -nodefaultlibs -nostdlib
CFLAGS+=-DNDEBUG
CFLAGS+=-fno-exceptions

-----Original Message-----
From: arm-gnu-bounces at codesourcery.com [mailto:arm-gnu-bounces at codesourcery.com] On Behalf Of Brad Badke
Sent: Friday, October 26, 2012 8:55 AM
To: Allen McIntosh; arm-gnu at codesourcery.com
Subject: Re: [arm-gnu] undefined reference to _init

This is what I am compiling with.
CFLAGS=-mcpu=cortex-a8
CFLAGS+=-mfpu=neon
CFLAG+=-mfpu=vfpv3-d16
CFLAGS+=-c ${${TARGET_MODE}_FLAG} -mlong-calls -fdata-sections 
CFLAGS+-funsigned-char -ffunction-sections -Wall ${IPATH} -Dgcc 
CFLAGS+${DEVICE_D} ${EVM_D} -D SUPPORT_UNALIGNED =-nostartfiles 
CFLAGS+-nodefaultlibs -nostdlib =-DNDEBUG =-fno-exceptions

-----Original Message-----
From: arm-gnu-bounces at codesourcery.com [mailto:arm-gnu-bounces at codesourcery.com] On Behalf Of Allen McIntosh
Sent: Thursday, October 25, 2012 5:59 PM
To: arm-gnu at codesourcery.com
Subject: Re: [arm-gnu] undefined reference to _init

On 10/25/2012 08:34 PM, Carlos O'Donell wrote:
> On 10/25/2012 8:29 PM, Brad Badke wrote:
>> So I have my application/RTOS running on an ARM Cortex-A8 using the 
>> free version of Code Sourcery (arm-none-eabi /4.6.3). My 
>> application/RTOS fully supports hardware floating point (neon). With 
>> the free version of the Code Sourcery math libraries the performance 
>> is pretty slow compared to the same code built with the ARM RVDS4.1 
>> tool chain.
>>
>> So I am curious if anyone can comment on how much performance would 
>> improve with the optimized libraries that come with the 
>> Personal/Standard/Professional editions. My application performs a 
>> lot of math.
> 
> Your application is the best benchmark.
> Go get a 30-day evaluation of the tools and try it out?
> http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebe
> nch/overview

There are other things you can do, with or without the 30 day trial.

1) If you can unit test your FP code and have access to a Cortex-A8 running Ubuntu 12.04, benchmark the unit test there.  IIRC you can compile both with and without hard FP.

2) Make sure you tell the compiler about your FP hardware.  I don't mean "hard" FP either.  Simple stuff like -mfpu=neon can make a big difference to the running time of your code if the compiler default is to generate code with one function call per FLOP.  Note however that it may not make much difference if you are spending most of your time in libm code.

Disclaimer: We licensed this product from Mentor.
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