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Altera_Forum's avatar
Altera_Forum
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21 years ago

assembly prog

Hi

Has anyone tried to write assembly language programs for nios II processor? If so plz tell me how to start the program i.e., i mean to say are any initial statements required like main() in c-lang. I wrote a sample program as follows but the error is that " %g0 not a valid register" , "%g1 not a valid register".

.text

MOVI %g0,9

MOV %g1,%g0

NOP

So someone please tell me how to overcome the problem

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    21 years ago

    Hi rakesh,

    You can find example assemble code in u-boot:

    -cpu/nios2/start.S

    -cpu/nios2/exceptions.S

    -lib_nios2/cache.S

    Regards,

    --Scott
  • Altera_Forum's avatar
    Altera_Forum
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    21 years ago

    you are writing NiosI asm for NiosII cpu ...

    here's something: 

        .file    "Main.s"
    .section    .text
    .align    3
    .global    main
    .type    main, @function
main:
    //sp <- sp -8
    addi    sp, sp, -8
    //ra -> *(sp +4)    
    stw  ra,4(sp)      
    // fp -> *(sp)
  stw  fp,0(sp)    
  // fp -> sp
    mov  fp,sp        
aaa:    //#define LED_BASE 0x00000820
    movhi    r13, %hiadj(0x00000820)
    addi    r13, r13, %lo(0x00000820)
    
    //valeur par bit (1) allume  (0) eteint
    movhi    r12, %hiadj(255)
    addi    r12, r12, %lo(255)
    
    //allume led
    stwio    r12, 0(r13)
    
    call    delay1
....
  • Altera_Forum's avatar
    Altera_Forum
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    21 years ago

    Thankyou smcnutt and slvn. I will be in touch with both of you if i have any more doubts.

  • Altera_Forum's avatar
    Altera_Forum
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    21 years ago

    rakesh,

    if you need more details about assembly and instruction. you should refer to reference and developper handbooks for Nios II.

    about the prog I did, it&#39;s just stupid and incomplete showing you what it looks like. (you were using Nios I assembly in your post I guess).

    If your SPOC has some leds you can replace Base Led by the address where are mapped your leds, and try something like turning the led on/off 

    file "Main.s"
.section .text
.align 3
.global main
.type main, @function
main:
    
//#define LED_BASE 0x00000820
movhi r13, %hiadj(0x00000820)
addi r13, r13, %lo(0x00000820)
//valeur par bit (1) allume  (0) eteint
movhi r12, %hiadj(255)
addi r12, r12, %lo(255)
//turn led on
stwio r12, 0(r13)
hope it can help
Sylvain