PrintCoords.asm

title N21

.386
.model flat,stdcall
.stack 4096
ExitProcess proto, dwExitCode:dword

include Irvine32.inc


;
; Library
;

; Wite a point and an index
WritePoint proto, point: COORD, index: WORD

; Write a character
WriteCharacter proto, character: BYTE

COORD STRUCT
	X WORD ? ; offset 00
	Y WORD ? ; offset 02
COORD ENDS


;
; End Library
;

.data
	coords COORD 10 DUP(<0,0>)
	forward BYTE "------------- Forward -------------",0
	reverse BYTE "------------- Reverse -------------", 0
.code

main proc 


	mov edx, OFFSET forward
	call WriteString
	call Crlf

	mov eax, TYPE coords
	mov ecx, LENGTHOF coords
	mov esi, 0
	mov ax, 1
	
	Increment: 
		mov coords[esi].X, ax
		mov bx, ax ; save the original index
		add ax, 1 ; increment one to the index for the y coordinate
		mov coords[esi].Y, ax ; coords[i].Y = i +1
		invoke WritePoint, coords[esi], bx ; WritePoint(coords[i], i)
		add esi, TYPE coords
	loop Increment
	
	call Crlf ; put a blank line in there!
	mov edx, OFFSET reverse
	call WriteString
	call Crlf

	; Go backwards and print them out in reverse order
	mov ecx, LENGTHOF coords
	Decrement:
		sub ax, 1
		sub esi, TYPE coords
		invoke WritePoint, coords[esi], ax
	loop Decrement
	

    invoke ExitProcess,0
main endp




; syntax sugar to reduce WriteChar to one line
WriteCharacter proc, character: BYTE

	push eax
	mov al, character
	call WriteChar
	pop eax

	ret
WriteCharacter endp



WritePoint proc, point: COORD, index: WORD
		
	push eax ; save eax
	push esi ; save esi

	mov eax, 0 ; reset eax so smaller numbers can be stored in ax

	mov ax, index
	call WriteDec ; write index
	invoke WriteCharacter, '.'
	invoke WriteCharacter, ' '
	invoke WriteCharacter, '('

	mov ax, point.X
	call WriteDec

	invoke WriteCharacter, ','
	invoke WriteCharacter, ' '

	mov ax, point.Y
	call WriteDec

	invoke WriteCharacter, ')'
	call Crlf;

	pop esi ; restore esi
	pop eax ; restore eax
	ret
WritePoint endp

end main