; I am horrible with ARM and I am having problems this is the program I wrote ; but it isn't working the right way it is supposed to do the fibonacci seq ; using indirect addressing it keeps looping back to when i LDR r0 ; what do i do to fix this? thanks AREA FIBSEQ,CODE SRAM_BASE EQU 0x04000000 ;static ram location ENTRY MAIN MOV r1,#0 ;first number used in sequence MOV r2,#1 ;second number used in sequence MOV r3,#0 ;third number used in sequence MOV r4,#1 ;counter LDR r5,=SRAM_BASE ; STR r3,[r5],#0 ;these are supposed to be the first numbers in the ;fib seq ; STR r4,[r5],#1 FIBO ;method that solves for fib up to 18th seq ADD r3,r2,r1 ADD r1,r1,r2 SUB r2,r2,r2 ADD r2,r3,r2 ;also having problems here with logic ADD r4,r4,#1 STR r3, [r5] ;here is where it loops back CMP r4,#18 BNE FIBO stop B stop END
Your Code doesn't compute the Fibonacci numbers because there are logical errors. Code for first 18 Fibonacci numbers:
1 | int SRAM_BASE[18]; |
2 | int main(void) |
3 | {
|
4 | int r1 = 0; // MOV r1,#0 |
5 | int r2 = 1; // MOV r2,#1 |
6 | int r3 = 0; // MOV r3,#0 |
7 | int r4 = 0; // MOV r4,#0 |
8 | int *r5 = SRAM_BASE; // LDR r5,=SRAM_BASE |
9 | |
10 | // Init 1st and 2nd Fibonacci numbers
|
11 | *r5++ = 0; // STR r3,[r5] |
12 | // ADD r5,r5,#1
|
13 | r4++; // ADD r4,r4,#1 |
14 | *r5++ = 1; // STR r3,[r5] |
15 | // ADD r5,r5,#1
|
16 | r4++; // ADD r4,r4,#1 |
17 | |
18 | // Compute following Fibonacci numbers
|
19 | do { |
20 | // FIBO:
|
21 | r3 = r2 + r1; // ADD r3,r2,r1 |
22 | *r5++ = r3; // STR r3,[r5] |
23 | // ADD r5,r5,#1
|
24 | r4++; // ADD r4,r4,#1 |
25 | r1 = r2; // MOV r1,r2 |
26 | r2 = r3; // MOV r2,r3 |
27 | } while( r4 != 18 ); // CMP r4,#18 |
28 | // BNE FIBO
|
29 | // STOP:
|
30 | while(1){} // B STOP |
31 | }
|
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