MIX C and Assembly in AtmelStudio

[Majid soltani]

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...

 

[Ian Rogers]

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....

 

[Majid soltani]

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

 

[Ian Rogers]

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

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???

 

[Majid soltani]

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 ");

 

[Ian Rogers]

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

 

[Majid soltani]

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

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.

 

[Ian Rogers]

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