CSC231 Homework 4 Solutions
--D. Thiebaut 21:52, 9 October 2012 (EDT)
Problem 1
;;; File: hw4a.asm
;;; Name: Emma Gould
;;; Account: 231a-ap
;;; Description: Computes and prints the first 10 32-bit Fibonacci terms.
;;; To Assemble, Link, and Run:
;;; nasm -f elf -F stabs hw4a.asm
;;; gcc -m32 -o hw4a driver.c asm_io.o hw4a.o
;;; ./hw4a
%include "asm_io.inc"
;; --------------------
;; data segment
;; --------------------
section .data
Fib dd 0x0 ; create an array of 10
dd 0x0 ; double-words (each 32 bits)
dd 0x0 ; and set them equal to 0
dd 0x0
dd 0x0
dd 0x0
dd 0x0
dd 0x0
dd 0x0
dd 0x0
;; --------------------
;; code area
;; --------------------
section .text
global asm_main
asm_main:
mov eax, 1 ; move 1 into eax
call print_int ; print the contents of eax ("1")
call print_nl ; print a new blank line
call print_int ; print the contents of eax ("1")
call print_nl ; print a new blank line
mov dword[Fib], eax ; move eax into Fib[0] -> 1
mov dword[Fib+4], eax ; move eax into Fib[1] -> 1
add eax, dword[Fib] ; add Fib[0] to eax -> 2
call print_int ; print the contents of eax ("2")
call print_nl ; print a new blank line
mov dword[Fib+8], eax ; move eax into Fib[2] -> 2
add eax, dword[Fib+4] ; add Fib[1] to eax -> 3
call print_int ; print the contents of eax ("3")
call print_nl ; print a new blank line
mov dword[Fib+12], eax ; move eax into Fib[3] -> 3
add eax, dword[Fib+8] ; add Fib[2] to eax -> 5
call print_int ; print the contents of eax ("5")
call print_nl ; print a new blank line
mov dword[Fib+16], eax ; move eax into Fib[4] -> 5
add eax, dword[Fib+12] ; add Fib[3] to eax -> 8
call print_int ; print the contents of eax ("8")
call print_nl ; print a new blank line
mov dword[Fib+20], eax ; move eax into Fib[5] -> 8
add eax, dword[Fib+16] ; add Fib[4] to eax -> 13
call print_int ; print the contents of eax ("13")
call print_nl ; print a new blank line
mov dword[Fib+24], eax ; move eax into Fib[6] -> 13
add eax, dword[Fib+20] ; add Fib[5] to eax -> 21
call print_int ; print the contents of eax ("21")
call print_nl ; print a new blank line
mov dword[Fib+28], eax ; move eax into Fib[7] -> 21
add eax, dword[Fib+24] ; add Fib[6] to eax -> 34
call print_int ; print the contents of eax ("34")
call print_nl ; print a new blank line
mov dword[Fib+32], eax ; move eax into Fib[8] -> 34
add eax, dword[Fib+28] ; add Fib[7] to eax -> 55
call print_int ; print the contents of eax ("55")
call print_nl ; print a new blank line
mov dword[Fib+36], eax ; move eax into Fib[9] -> 55
;; return to C program
ret
Problem 2
;;; File: hw4b.asm
;;; Name: Emma Gould
;;; Account: 231a-ap
;;; Description: Computes and prints the first 10 16-bit Fibonacci terms.
;;; To Assemble, Link, and Run:
;;; nasm -f elf -F stabs hw4b.asm
;;; gcc -m32 -o hw4b driver.c asm_io.o hw4b.o
;;; ./hw4b
%include "asm_io.inc"
;;; --------------------
;;; data segment
;;; --------------------
section .data
Fib dw 0x0 ; create an array of 10
dw 0x0 ; words (each 16 bits)
dw 0x0 ; and set them equal to 0
dw 0x0
dw 0x0
dw 0x0
dw 0x0
dw 0x0
dw 0x0
dw 0x0
;;; --------------------
;;; code area
;;; --------------------
section .text
global asm_main
asm_main:
mov eax, 0 ; move 0 into eax
mov ax, 1 ; move 1 into ax
call print_int ; print the contents of ax ("1")
call print_nl ; print a new blank line
call print_int ; print the contents of ax ("1")
call print_nl ; print a new blank line
mov word[Fib], ax ; move ax into Fib[0] -> 1
mov word[Fib+2], ax ; move ax into Fib[1] -> 1
add ax, word[Fib] ; add Fib[0] to ax -> 2
call print_int ; print the contents of ax ("2")
call print_nl ; print a new blank line
mov word[Fib+4], ax ; move ax into Fib[2] -> 2
add ax, word[Fib+2] ; add Fib[1] to ax -> 3
call print_int ; print the contents of ax ("3")
call print_nl ; print a new blank line
mov word[Fib+6], ax ; move ax into Fib[3] -> 3
add ax, word[Fib+4] ; add Fib[2] to ax -> 5
call print_int ; print the contents of ax ("5")
call print_nl ; print a new blank line
mov word[Fib+8], ax ; move ax into Fib[4] -> 5
add ax, word[Fib+6] ; add Fib[3] to ax -> 8
call print_int ; print the contents of ax ("8")
call print_nl ; print a new blank line
mov word[Fib+10], ax ; move ax into Fib[5] -> 8
add ax, word[Fib+8] ; add Fib[4] to ax -> 13
call print_int ; print the contents of ax ("13")
call print_nl ; print a new blank line
mov word[Fib+12], ax ; move ax into Fib[6] -> 13
add ax, word[Fib+10] ; add Fib[5] to ax -> 21
call print_int ; print the contents of ax ("21")
call print_nl ; print a new blank line
mov word[Fib+14], ax ; move ax into Fib[7] -> 21
add ax, word[Fib+12] ; add Fib[6] to ax -> 34
call print_int ; print the contents of ax ("34")
call print_nl ; print a new blank line
mov word[Fib+16], ax ; move ax into Fib[8] -> 34
add ax, word[Fib+14] ; add Fib[7] to ax -> 55
call print_int ; print the contents of ax ("55")
call print_nl ; print a new blank line
mov word[Fib+18], ax ; move ax into Fib[9] -> 55
;;; return to C program
ret
Problem 3
;;; hw4c.asm
;;; Yoshie 10/2/12 (edited by D. Thiebaut)
;;;
;;; This program computes and prints the first 10 16-bit
;;; "special "Fibonacci terms using a C "wrapper" program
;;;
;;; The "special" Fibonacci terms are calculated as follows:
;;;
;;; F(1) = 1
;;; F(2) = 1
;;; F(N) = F(N-1) * 2 + F(N-2) - 1
;;;
;;; Prints a modified Fibonacci series:
;;;
;;; 1 1
;;; 2 1
;;; 3 2
;;; 4 4
;;; 5 9
;;; 6 21
;;; 7 50
;;; 8 120
;;; 9 289
;;; 10 697
;;;
;;; To assemble:
;;; nasm -f elf -F stabs hw4c.asm
;;; gcc -m32 -o hw4c.asm driver.c asm_io.o hw4c.o
;;; ./hw4c.asm
%include "asm_io.inc"
;; -------------------------
;; data segment
;; -------------------------
section .data
;;None
;; -------------------------
;; code area
;; -------------------------
section .text
global asm_main
asm_main:
mov eax, 0 ;eax initialize all content to 0's
mov bx, 1 ;bx will hold the counter, first term
mov ax,bx ;counter->ax, printed
call print_int
mov ax,0x20 ;" "->ax and printed
call print_char
mov ax, 1 ; F(1)->ax, printed and a new line is called
call print_int
call print_nl
mov cx, ax ;cx will carry the F(n-2 term) where F(n)<2
inc bx ;Second row/term, moved to ax and printed
mov ax,bx
call print_int
mov ax,0x20 ;" "->ax and printed
call print_char
mov ax, 1 ; F(2)->ax, printed and a new line is called
call print_int
call print_nl
mov dx, ax ;dx will carry the F(n-1) term where F(n)<2
inc bx ;Third row/term, printed
mov ax, bx
call print_int
mov ax, 0x20 ;" "->ax and printed
call print_char
mov ax, dx ;Make ax carry F(n-1), or F(2)=1
add ax, ax ;Multiply F(2) by 2
dec cx ;Minus F(n-1) or F(1) by 1
add ax, cx ;Add F(2)*2+(F(1)-1), print int and new line
call print_int
call print_nl
mov cx,dx ;Set the new F(n-2) for the next term
mov dx,ax ;Set the new F(n-1) for the next term
;The same code as the third term is used to print the rest of the series
inc bx ;Fourth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax, dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx,ax
inc bx ;Fifth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax, ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx, ax
inc bx ;Sixth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx,ax
inc bx ;Seventh row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx,ax
inc bx ;Eighth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx,ax
inc bx ;Ninth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
mov cx,dx
mov dx,ax
inc bx ;Tenth row/term
mov ax, bx
call print_int
mov ax,0x20
call print_char
mov ax,dx
add ax,ax
dec cx
add ax, cx
call print_int
call print_nl
;; return to C program
ret
