what is meant by '' @tiny '' instruction

[raunaque]

Posted on October 29, 2004 at 08:37

what is meant by '' @tiny '' instruction

[raunaque]

Posted on October 29, 2004 at 04:47

Hi

i knew to firmware writing . i want to know what does the statement

@tiny means.

suppose i define

#define abc @tiny

what does this statement actually do ?

Thanks in Advance

Ronnie

[wolfgang2399]

Posted on October 29, 2004 at 08:37

Hi Ronnie,

in the Cosmic Compiler the @tiny modifier forces a variable to be explicitely allocated in zero page. In the compiled assembler code this variable will then be addressed in short addressing mode. See also C Cross Compiler User's Guide for ST7 (Cosmic), chapter 3 at Placing DataObjects in Short Range Memory (page 3-13ff).

- Example:

@tiny char c_tiny; /* short addressing mode */

@near char b_near; /* long addressing mode */

....

c_tiny = b_near;

....

b_near = c_tiny;

....

-> Resulting assembler code:

....

F107 c60123 LD A,b_near

F10a b7C1 LD c_tiny,A

....

F11e b6C1 LD A,c_tiny

F120 c70123 LD b_near,A

The @tiny modifier helps you in optimizing your resulting code, especially if you are using bit operations.

The Metrowerks Compiler uses #pragma directives instead.

With your #define statement the compiler only substitutes the term @tiny for abc in your program.

Hope it helps and good luck

WoRo