MIX C and Assembly in AtmelStudio

Hi my friend...

I declare this variable :

const unsigned char screen_pattern[8*8] PROGMEM = {
10,20,0,11,0,125,255,13,
10,20,0,0,0,125,255,13,
10,20,115,90,0,125,255,13,
10,20,0,0,0,125,255,13,
10,47,0,0,0,125,255,13,
10,120,0,80,0,125,255,13,
10,200,0,0,0,125,255,13,
10,20,0,127,0,125,255,13
};

now ... i want mix C and Assembly code and send screen_pattern to PORTD with assembly code .... please help me...

In the documentation it will show how to use assembly within the C environment... It will be quite straight forward...

I don't use avr studio so I'm not sure....

you use which compiler ? ... please you say your solution maybe i could use that.

Majid soltani said:

you use which compiler ? ... please you say your solution maybe i could use that.

Click to expand...

I use Pic's.... I don't think my compiler would be much use to you.. I haven't a copy of the GNU C compiler to hand...

Are you using AVR studio???

OK thank you.... Yes , I use atmelStudio 6

now i solved my problem

first i set an assembly name to screen_pattern[] :

const unsigned char screen_Pattern[8*8] asm("sc_p") PROGMEM = {
67,20,0,11,0,125,255,13,
10,20,0,0,0,125,255,13,
10,20,115,90,0,125,255,13,
10,20,0,0,0,125,255,13,
10,47,0,0,0,125,255,13,
10,120,0,80,0,125,255,13,
10,200,0,0,0,125,255,13,
10,20,0,127,0,125,255,13
};


then use this codes :


asm ("PUSH R16 ");
asm ("PUSH R30 ");
asm ("PUSH R31 ");

// Z Register is ( R31:R30)

asm ("LDI r30,lo8(sc_p)"); // R30 = LOW(sc_P)

asm ("LDI r31,hi8(sc_p)"); // R31 = HIGH(sc_P)

asm ("LPM R16 , Z "); // LPM (Load program memory) R16 = [Z] Z = first cell of screen_Pattern[]
asm ("OUT 0x12 , R16 "); // 0x12 is address of PORTD ; PORTD=R16

asm ("POP R31 ");
asm ("POP R30 ");
asm ("POP R16 ");

Why are you wanting to use C... If you are going to program in ASM just use an assembler??

Ian Rogers said:

Why are you wanting to use C... If you are going to program in ASM just use an assembler??

Click to expand...

Because ,I in a part of program have time limits and in other parts of the program do not need to spend own time writing code in assembly language.

Okay... Some of my functions are just ASM wrappers as well.... When the fastest code possible is needed..