Difference between revisions of "CSC231 Fibonacci with Loops"
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ret | ret | ||
</source> | </source> | ||
| − | <br />] | + | <br /> |
| + | =Example 2= | ||
| + | <br /> | ||
| + | <source lang="asm"> | ||
| + | ;;; fibWithLoop2.asm | ||
| + | ;;; D. T. | ||
| + | ;;; a simple demo program computing a few Fibonacci terms | ||
| + | ;;; using indirect addressing modes and loops | ||
| + | ;;; To compile and run | ||
| + | ;;; nasm -f elf fibWithLoop2.asm | ||
| + | ;;; nasm -f elf asm_io.asm | ||
| + | ;;; gcc -m32 -o fibWithLoop2 driver.c fibWithLoop2.o asm_io.o | ||
| + | ;;; ./fibWithLoop2 | ||
| + | |||
| + | %include "asm_io.inc" | ||
| + | |||
| + | ;; ------------------------- | ||
| + | ;; data segment | ||
| + | ;; ------------------------- | ||
| + | section .data | ||
| + | Fib db 0,0,0,0,0,0 | ||
| + | |||
| + | ;; ------------------------- | ||
| + | ;; code area | ||
| + | ;; ------------------------- | ||
| + | section .text | ||
| + | global asm_main | ||
| + | asm_main: | ||
| + | mov ebx, 0 ; make ebx point to array | ||
| + | mov ecx, 5 ; # of terms to compute | ||
| + | mov eax, 1 ; first term as double word (for printing) | ||
| + | mov byte [Fib+ebx], al ; set 1st term | ||
| + | call print_int ; print it | ||
| + | call print_nl | ||
| + | |||
| + | mov byte [Fib+ebx+1], al ; set 2nd term | ||
| + | call print_int ; print it | ||
| + | call print_nl | ||
| + | |||
| + | sub ecx,2 ; adjust counter | ||
| + | add ebx,2 ; and pointer. ebx points to | ||
| + | ; empty Fib | ||
| + | |||
| + | for: add al, byte [Fib+ebx-2] ; al<- fib(n-1)+fib(n-2) | ||
| + | mov byte [Fib+ebx], al ; store new term | ||
| + | call print_int ; print it | ||
| + | call print_nl | ||
| + | |||
| + | inc ebx ; point to new term | ||
| + | loop for ; loop back | ||
| + | |||
| + | ;; return to C program | ||
| + | |||
| + | ret | ||
| + | </source> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | <br /> | ||
| + | [[Category:CSC231]] | ||
Revision as of 09:06, 10 October 2012
--D. Thiebaut 09:01, 10 October 2012 (EDT)
Example 1
;;; fibWithLoop.asm
;;; D. T.
;;; a simple demo program computing a few Fibonacci terms
;;; using indirect addressing modes and loops.
;;; To compile and run
;;; nasm -f elf fibWithLoop.asm
;;; nasm -f elf asm_io.asm
;;; gcc -m32 -o fibWithLoop driver.c fibWithLoop.o asm_io.o
;;; ./fibWithLoop
%include "asm_io.inc"
;; -------------------------
;; data segment
;; -------------------------
section .data
Fib db 0,0,0,0,0,0
;; -------------------------
;; code area
;; -------------------------
section .text
global asm_main
asm_main:
mov ebx, Fib ; make ebx point to array
mov ecx, 5 ; # of terms to compute
mov eax, 1 ; first term as double word (for printing)
mov byte[ebx], al ; set 1st term
call print_int ; print it
call print_nl
mov byte[ebx+1], al ; set 2nd term
call print_int ; print it
call print_nl
sub ecx,2 ; adjust counter
add ebx,2 ; and pointer. ebx points to
; empty Fib
for: add al, byte[ebx-2] ; al<- fib(n-1)+fib(n-2)
mov byte[ebx], al ; store new term
call print_int ; print it
call print_nl
inc ebx ; point to new term
loop for ; loop back
;; return to C program
ret
Example 2
;;; fibWithLoop2.asm
;;; D. T.
;;; a simple demo program computing a few Fibonacci terms
;;; using indirect addressing modes and loops
;;; To compile and run
;;; nasm -f elf fibWithLoop2.asm
;;; nasm -f elf asm_io.asm
;;; gcc -m32 -o fibWithLoop2 driver.c fibWithLoop2.o asm_io.o
;;; ./fibWithLoop2
%include "asm_io.inc"
;; -------------------------
;; data segment
;; -------------------------
section .data
Fib db 0,0,0,0,0,0
;; -------------------------
;; code area
;; -------------------------
section .text
global asm_main
asm_main:
mov ebx, 0 ; make ebx point to array
mov ecx, 5 ; # of terms to compute
mov eax, 1 ; first term as double word (for printing)
mov byte [Fib+ebx], al ; set 1st term
call print_int ; print it
call print_nl
mov byte [Fib+ebx+1], al ; set 2nd term
call print_int ; print it
call print_nl
sub ecx,2 ; adjust counter
add ebx,2 ; and pointer. ebx points to
; empty Fib
for: add al, byte [Fib+ebx-2] ; al<- fib(n-1)+fib(n-2)
mov byte [Fib+ebx], al ; store new term
call print_int ; print it
call print_nl
inc ebx ; point to new term
loop for ; loop back
;; return to C program
ret
