TMS570LS3137 FPU module

If you compiled your code for floating point support and the FPU wasn't enabled - you would be getting undefined instruction exceptions.  So likely your FPU is enabled.  But you can check this by checking the FPEXC register (refer to Cortex R4 TRM for details) bit 30 is the VFP enable.

You should:

1) try the Cortex R4F CMSIS DSP library implementation of the function you need

2) make sure that you are compiling with optimization on and not with debug.

3) make sure that the device is initilized correctly (max freq.,  flash pipeline enabled w. correct wait states).

4) try compiling for the Thumb2 instruction set instead of the ARM instruction set.

Anthony Seely，

you say that , 

You should:

1) try the Cortex R4F CMSIS DSP library implementation of the function you need

2) make sure that you are compiling with optimization on and not with debug.

3) make sure that the device is initilized correctly (max freq.,  flash pipeline enabled w. correct wait states).

4) try compiling for the Thumb2 instruction set instead of the ARM instruction set.

To use the  FPU,I must be insure the above 4 item is correct?

Now:

1. I do not use Cortex R4F CMSIS DSP library,the library is must be use to use FPU?

2. I now optimization level = 3;   optimize for speed  = 5; in release configuration

3. If  I  use HALCOGEN to generate the initilized program to the device,  is the  device can  be initilized correctly? if        not,how can I   flash pipeline enabled w. correct wait states?

4.  How can I set  Thumb2 instruction set  when I compiling ?

Best Regards,
Wang

Anthony Seely，

Do you have an example program to use the FPU?  if you have the example program ,can you email it to me?
thank you !

Best Regards,
Wang

 Anthony Seely，

 I check the FPEXC register bit 30  ,this bit is set, so the FPU is enable .

Best Regards,
Wang

Hi Wang,

These suggestions are mainly targetted at addressing your concern about performance - not basic functionality.

user4089018 said:

To use the  FPU,I must be insure the above 4 item is correct?

user4089018 said:

1. I do not use Cortex R4F CMSIS DSP library,the library is must be use to use FPU?

user4089018 said:

2. I now optimization level = 3;   optimize for speed  = 5; in release configuration

Ok that's good.

user4089018 said:

3. If  I  use HALCOGEN to generate the initilized program to the device,  is the  device can  be initilized correctly? if        not,how can I   flash pipeline enabled w. correct wait states?

Yes usually.  You can disable the FPU on the R4-MPU-PMU tab but you would have had to go out of your way to do this; the default is enabled.  HalCoGen should base the flash wait states automatically on your clock freq to prevent this from being wrong.

user4089018 said:

4.  How can I set  Thumb2 instruction set  when I compiling ?

There is a build option in CCS, under the Arm Compiler - Processor options tab for code state.  You want 16 and not 32 for thumb 2.

I am not sure Thumb2 will improve performance.  It does in some benchmarks.  The floating point instructions are all 32-bit Thumb2** so it will not improve the float functions much but it might improve surrounding instructions and if these are in your critical 'loops' it could add up. 

**[Thumb2 is variable length some opcodes are 16 bit and some are 32-bit... but the CCS option is still called 16-bit which is a hold-over from older parts that just had Thumb.]

Hi Wang,
I'd encourage you to try the DSPLIB and it's examples as these should give you the best performance.

Hi Anthony Seely，
      
    I have download <Hercules Safety MCU Cortex-R4 CMSIS DSP Library (v1.0.0) >,and I install it ,but how can I use it ?   DO you have a document to tell me  
how can I use   Hercules Safety MCU Cortex-R4 CMSIS DSP Library?
   
thanks a lot

Best Regards,
wang