TMS320C6670: C66x ALU test, Link register

Sofiene Bk

Part Number: TMS320C6670

Hello,

I have a question regarding C66x controller.

I am writing safety tests for the ALU units, so basically am writing an assembler code to test the 8 units L1,L2, M1, M2 D1, D2 and S1 and S2.
I did that for ARM micro-controller where you have a link register that used to stores the return address, such as when making a function call.

So my first question: Do we have something similar in c66x? If not is that done automatically?
Second question: How to call an external function using one of the assembler instruction (something similar the B instruction that i used for local branch)?

Please find below a snip of my code where I test the ADD instruction, let me know where are the wrong part in that code:

.asg B15, SP
.global PAL_AluTest_v_ArithInstructions_ASM

PAL_AluTest_v_ArithInstructions_ASM:
STW .D2T1 A1,*SP++(-4) ; save A1
STW .D2T1 A2,*SP++(-4) ; save A2
STW .D2T1 A3,*SP++(-4) ; save A3
STW .D2T1 A4,*SP++(-4) ; save A4
STW .D2T1 A5,*SP++(-4) ; save A5

MVD .M1 A0, A5 ; MVD (.unit) src2, dst
MVK .S1 40, A1 ; Set A1 register to a specific value in that case 40
MVK .S1 60, A2 ; Set A2 register to a specific value in that case 60
MVK .S1 100, A3 ; Set A3 register to a the expected value in that case A3= A1+A2
ADD .L1 A1, A2, A4 ; Apply ADD operation to L1 unit (ADD (.unit) src1, src2, dst)
CMPEQ .L1 A4, A3, A0 ; CMPEQ (.unit) src1, src2, dst
[ A0] B .S1 Arithmatic_Ovr ; B (.unit) label
[!A0] B .S1 ARITHMATIC_ERR ; B (.unit) label

ARITHMATIC_ERR:
CALLP .S2 External_Function_Name, B3 ;in case of issue an external function will report the error

Arithmatic_Ovr:
MVD .M1 A5, A0 ; MVD (.unit) src2, dst
LDW .D2T1 *++SP(4), A5 ; LDW (.unit) *+baseR[offsetR], dst
LDW .D2T1 *++SP(4), A4 ; LDW (.unit) *+baseR[offsetR], dst
LDW .D2T1 *++SP(4), A3 ; LDW (.unit) *+baseR[offsetR], dst
LDW .D2T1 *++SP(4), A2 ; LDW (.unit) *+baseR[offsetR], dst

LDW .D2T1 *++SP(4), A1 ; LDW (.unit) *+baseR[offsetR], dst

Best Regards,

Sofiene Bk

over 2 years ago

0 Ralph Jacobi over 2 years ago

TI__Guru*** 135135 points

Hello Sofiene,

As stated on the device product page, this device does not have ongoing direct design support from TI and we cannot help with this question.

There are list of third parties on the product page so I'll provide an FAQ post that has their contact info. This device isn't listed on the FAQ, so the collateral on it won't be of use, but at least it will get you the details for the third parties: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/813421/faq-davinci-digital-media-devices-support-guidance-dm335-dm355-dm365-dm368-dm369-dm3725-dm3730-dm383-dm385-dm388-dm505-dm640-dm642-dm643-dm6431-dm6433-dm6435-dm6437-dm6441-dm6443-dm6446-dm6467-dm6467t-dm647-dm648-etc

Best Regards,

Ralph Jacobi

0 Victor Kazmirenko over 2 years ago

Guru 13202 points

Hello,

I'm afraid to be of little help here, nevertheless, to the best of my knowledge stack is used to remember function return address, and already you alias SP to B15 register, which is traditionally used for stack pointer in C6x. And since you are fluent in assembly, why don't you refer TMS320C66x DSP CPU and Instruction Set in SPRUGH7 at https://www.ti.com/lit/ug/sprugh7/sprugh7.pdf together with TMS320C6000 Assembly Language Tools User's Guide in SPRU186W at https://www.ti.com/lit/ug/spru186w/spru186w.pdf

0 Victor Kazmirenko over 2 years ago in reply to Ralph Jacobi

Guru 13202 points

Hello Ralph,

Though that is not my particular business, I find it so sad that user request is carelessly rejected due to device being out of direct support. Though user honestly listed C6670, the essence of the question was about C66 core and assembly implementation. So if user asked about no part, or C6678, or any K2 with C66 core the request would be legit.

0 Sofiene Bk over 2 years ago in reply to Ralph Jacobi

Prodigy 55 points

Thank you for you answer.

My question was about assembler code and how to handle link register and external function call for c66x controller.
What you send to me doesn't help me to resolve my issue!

Best regards,

Sofiene Bk

0 Sofiene Bk over 2 years ago in reply to Victor Kazmirenko

Prodigy 55 points

Hi Victor,

Yes you are right by using B15 as SP i can first store the values of the A registers (A1-->A5) and later when i load them at the end of the test, the stack pointer will point to the initial value before the store instruction.

Thank you for your answer

Best regards
Sofiene Bk

0 Ralph Jacobi over 2 years ago in reply to Victor Kazmirenko

TI__Guru*** 135135 points

Hi Victor,

Thanks for your comments. I was never given any formal training regarding the workings of these designated 'no support' devices so I hadn't considered that this was more of a general C66x question. I'll keep that in mind for future questions and thanks for your supplied reply.

Sofiene, has Victor's answer resolved your question at this point?

Best Regards,

Ralph Jacobi

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TMS320C6670: C66x ALU test, Link register