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ECSE436 Tutorial Assembly and Linear Assembly Evgeny Kirshin, 05/10/2011.

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Presentation on theme: "ECSE436 Tutorial Assembly and Linear Assembly Evgeny Kirshin, 05/10/2011."— Presentation transcript:

1 ECSE436 Tutorial Assembly and Linear Assembly Evgeny Kirshin, 05/10/2011

2 E. Kirshin Outline Introduction to Assembly Linear Assembly AMR Reading Demo: simple sine-wave generator

3 E. Kirshin TMS320 Assemby Language

4 E. Kirshin C6000 ISA

5 E. Kirshin Instruction Packing

6 E. Kirshin Sample Instructions

7 E. Kirshin Sample Instruction

8 E. Kirshin Instruction List

9 E. Kirshin Instruction List

10 E. Kirshin C program calling and ASM function

11 E. Kirshin C program calling and ASM function -Values passed to the assembly functions using registers : A4,B4,A6,B6 and so on -Only registers A1,A2,B0,B1,B2 can be used as conditional registers -B3 contain the return address -A4 is the return value -Need to take into account the NOP

12 E. Kirshin Linear Assembly To effectively program a DSP using assembly language, you need to do the scheduling by hand! Need to account for the number of clock cycles each functional unit takes, etc… Difficult, so TI has linear assembly –you don’t have to schedule it, the compiler does it for you –can use CPU resources without worrying about scheduling, register allocation, etc…

13 E. Kirshin What is Linear Assembly ? C code TI Linear Assembly Assembly Efficiency Ease of use

14 E. Kirshin What is Linear Assembly ? It is a cross between C and Assembly It lets you : use symbolic names forget pipeline issues ignore putting NOPs, parallel bars, functional units, register names more efficiently use CPU resources than C (e.g., hardware circular buffers) Enables you to write assembly-like programs

15 E. Kirshin File extensions File extension for c is.c File extension for linear assembly is.sa File extension for low-level assembly is.asm

16 E. Kirshin Example Dot Product From Chassaing //DOTPclasm.c short dotp4clasmfunc(short *a, short *b, short ncount); #include #define count 4 short x[count] = {0,1,2,3}; short y[count] = {100, -20, 30, -20}; volatile int result = 0; main() { result = dotp4clasmfunc(x,y,count); printf("result = %d decimal \n", result); } Function written in LASM

17 E. Kirshin.def_dotp4clasmfunc _dotp4clasmfunc:.cproc ap, bp, count.reg a, b, prod, sum zero sum loop:ldh *ap++,a ldh*bp++,b mpya,b,prod addprod,sum,sum subcount,1,count [count]bloop.returnsum.endproc The LASM code Example Dot Product From Chassaing

18 E. Kirshin.def_dotp4clasmfunc Define and ASM function called from C Start a section of Linear assembly _dotp4clasmfunc:.cproc ap, bp, count Name of the function Arguments of the function Set up your variables (similar to C).reg a, b, prod, sum Example Dot Product From Chassaing

19 E. Kirshin zero sum Initialize your sum to zero Load the value from memory pointed by ap, copy it to register a and increment the pointer by 1 ldh *ap++,a Do the same thing with b ldh*bp++,b ldh stands for load half word (a short in C) Example Dot Product From Chassaing

20 E. Kirshin Multiply a and b and write the result to prod mpya,b,prod Add sum and prod and write the result to sum addprod,sum,sum Decrement count by 1 subcount,1,count Example Dot Product From Chassaing

21 E. Kirshin If count is different than 0, branch to loop Return sum as the output of your function (exactly Like the return command in C) End linear assembly function.endproc [count]bloop.returnsum Example Dot Product From Chassaing

22 E. Kirshin Circular Addressing

23 E. Kirshin AMR Addressing mode register Read Chassaing at pages : 82-83

24 E. Kirshin AMR Addressing mode register

25 E. Kirshin AMR Addressing mode register How to modify the AMR ? MVKL.S20x0004,B2 MVKH.S20x0005,B2 MVC.S2B2,AMR MVC is the only function which can modify the content of a control register Be sure to reset the AMR at the end of your function Also, do the same inside your interrupt routine, check the book by Chassaing to know how to modify the AMR from C There is a good description on how AMR works in SPRA645, see further

26 E. Kirshin References: TI documents TMS320C6000 Optimizing Compiler User's Guide (SPRU187). Chapter 4 contains the description of the directives (.trip,.cprog,.reg, etc.) TMS320C67x/C67x+ DSP CPU and Instruction Set Reference Guide (SPRU733). Contains the description of the instruction set (add, mpy, sub, mv, etc.) TMS320C6000 Assembly Language Tools (SPRU186V). Circular Buffering on TMS320C6000 (SPRA645). Nice description of hardware circular buffering and the AMR register

27 E. Kirshin References: books Chaissaing, pages : and Kuo and Gan, pages : Additional book: S.A.Tretter. Communication System Design Using DSP Algorithms. SpringerLink, 2008 Contains good description of the AIC, McBSP, interrupts and sine-wave generation examples. Available online in PDF (from McGill).

28 E. Kirshin Questions ?


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