• Locked Locked
  • Replies 3 replies
  • Subscribers 119 subscribers
  • Views 4422 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

noob question: ARM equivalents for Thumb opcodes

richard cooper
Note: This was originally posted on 15th September 2011 at http://forums.arm.com

Trying to get Google's VP8 ARM code working under WinCE, but would like to see how much faster things are with it's ARM ASM code. I am using ARMASM to process the .ASM files using the following switches:


ARMASM -32 -ARCH 6 FileName.asm


Most of the files compile fine except for some that involve transforms, namely: iwalsh_v6.asm, walsh_v6.asm, etc. Turns out that these are the most critical for any performances improvements to be gained.


When I compile these modules I seem to be getting the following errors:

Unknown opcode: ASRS ( i.e. asrs r6,r7, #16)

Unknown opcode: LSL ( i.e. lsl r3,r7,#16)

Unknown opcode: ASR (i.e. asr r2, r4, #3)

Unknown opcode: LSLS (i.e. lsls r6, r7, #16)


I really don't know much about ARM assembler yet, but am willing to take a stab at trying to convert these opcodes to regular ARM opcodes if at all possible.

Can the aforementioned opcodes be converted to regular ARM opcodes, or is this a waste of time.



Thanks.
Parents
  • Note: This was originally posted on 16th September 2011 at http://forums.arm.com

    I am down to a single ARM opcode.


    Is there a synonymous was to re-write the following expression:


    ldrd        r4, r5, [r0]        ;       [i1 | i0] [i3 | i2]


    Error emitted:  [size="1"]illegal expression type; expected program relative)
    [/size]



    in terms of ldr? It seems that this can be done: "The LDM, STM, LDRD, and STRD instructions might be replaced by equivalent ARM instructions".


    However, I can't seem to find how to do this due to my aneamic understanding of ARM.

    Thanks.
Reply
  • Note: This was originally posted on 16th September 2011 at http://forums.arm.com

    I am down to a single ARM opcode.


    Is there a synonymous was to re-write the following expression:


    ldrd        r4, r5, [r0]        ;       [i1 | i0] [i3 | i2]


    Error emitted:  [size="1"]illegal expression type; expected program relative)
    [/size]



    in terms of ldr? It seems that this can be done: "The LDM, STM, LDRD, and STRD instructions might be replaced by equivalent ARM instructions".


    However, I can't seem to find how to do this due to my aneamic understanding of ARM.

    Thanks.
Children
No data