How to define a floating point constant in assembly language

Walter Snafu

This is an easy question, and I'm sorry for asking it, but I'm not finding the answer in the manuals.

In assembly language, I want to use the MVKL and MVKH instructions to load an immediate floating point constant into a register. Something like this:

MVKL (5.5e-22), A10
MVKH (5.5e-22), A10

How do I do that?

Thanks for your help.

Note: I found the ".float" directive in the TMS320C6000 Assembly Language Tools v7.3 User's Guide, but it doesn't describe how to achieve the above result.

over 13 years ago

0 Archaeologist over 13 years ago

TI__Guru* 84285 points

           MVKL    .S1     0x1c263a30,A4
           MVKH    .S1     0x1c263a30,A4

Not particularly friendly, I'll admit. I've submitted enhancement request SDSCM00044109 to allow float constants here.

0 Walter Snafu over 13 years ago in reply to Archaeologist

Genius 3450 points

Thanks Mastermind Archaeologist. Until the upgraded feature is in place, it looks like I'll have to do the conversion myself. May I ask how you converted the floating point number to a 32-bit hex constant? Is there a way to fool CCS into making the conversion for me, and then I plug it into my code by hand?

Thanks for your help.

0 Archaeologist over 13 years ago in reply to Walter Snafu

TI__Guru* 84285 points

There are plenty of converters online, or you could use the compiler and look at the generated assembly code. Unix example follows:

% cat example.c
float example(void) { return 5.5e-22f; }
% cl6x -k example.c
% grep MV example.asm 
           MVKL    .S1     0x1c263a30,A4
           MVKH    .S1     0x1c263a30,A4

0 Walter Snafu over 13 years ago in reply to Archaeologist

Genius 3450 points

Thanks Archaeologist! That answers my questions.

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How to define a floating point constant in assembly language