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How to read/write a double/float variable using VB scripting

Anuj Aggarwal
Expert 3990 points

Hi,

I need some help in the thread below:

http://e2e.ti.com/support/dsp/tms320c6000_high_performance_dsps/f/112/p/93656/325750.aspx#325750

Basically, I need to modify a double/float variable using VB scripting but having issues in writing and reading back the updated value. Any pointers?

Thanks in advance.

  • 0
    TI__Guru**** 482781 points

    Hi Anuj,

    I'm waiting for an example from Mukul. If you have an example also, I'd like to see it.

    Thanks

    ki

  • 0 in reply to Ki
    Prodigy 115 points

    ' start_point is a float in 'C' code

    'default value in start_point 4.0

    'I want to write 1.0 or 1.5 in this variable using VB

    'If I see this in step by step debugging after write start_eb_no shows some junk value instead of 1.0

    ' Read value is always what I set but not in C

    ' Here is the code snippet

    Dim mk As Double
    Dim dspAddr As Long
    Dim nLength As Long

    dspAddr = MyCCScripting.SymbolGetAddress("start_point")

    mk = Worksheets("Sheet1").Cells(FIRST_TEST_RAW + k, COLD_CACHE_COL)

    Call MyCCScripting.MemoryWrite(CCS_SCRIPTING_COMLib.PAGE_DATA, _

                                   dspAddr, _

                                   nLength, _

                                   mk)

    mk = MyCCScripting.MemoryRead(CCS_SCRIPTING_COMLib.PAGE_DATA, _

                                     dspAddr, _

                                     nLength, _

                                     False)

  • 0 in reply to Mukul Kabra
    TI__Expert 3990 points

    Ki,

    Do you have any updates on this?

    Thanks.

  • 0 in reply to Anuj Aggarwal
    TI__Guru**** 482781 points

    Hi Anuj, Mukul,

    My apologies for the delay, I have been away for a few weeks.

    There are two main limitations with CCScripting here:

    1) The CCScripting Memory Write API only takes an integer type for the value so any float type will be converted to an integer, then written as an integer value (same does with the read).

    2) The CCScripting Memory Read/Write APIs have a limitation of a max of 32 bits for the length to read/write. Since you are trying to write to a double type (I am assuming "start_point" is a double type) and a double is 64 bits on a C6000, this write will fail with 32 bits specified as the length... or at least not properly write the value as you are expecting it to. If you want to write a value to a double type on the target, you will need to do two consecutive 32-bit int memory writes (0x0 and 0x3FF00000 for value 1.0 on a little endian C6000 target)

    Call MyCCScripting.MemoryWrite(0, _
                                   dspAddr, _
                                   32, _
                                   0)
                                  
    Call MyCCScripting.MemoryWrite(0, _
                                   dspAddr + 4, _
                                   32, _
                                   Val("&H3FF00000"))

    Thanks

    ki