Category : Assembly Language Source Code
Archive   : ASM-SUBR.ZIP
Filename : GMESSOUT

;-------------------------gmessout routine begins--------------------------+
; NAME GMESSOUT
;
; from BLUEBOOK OF ASSEMBLY ROUTINES FOR IBM PC & XT.
; page : 154

; ROUTINE FOR PRINTING A STRING ON THE GRAPHICS SCREEN
;
; FUNCTION: This routine prints a messgae on the graphics screen, using
; the SCHAR or RCHAR routines. The message terminates in a zero.
;
; INPUT: Upon entry:
;
; address of message is in SI
; x-coord of upper LH corner is in xmess
; y-coord of upper LH corner is in ymess
; horiz magnitude of characters is in xmagn
; vert magnitude of characters is in xmagn
; color of chars is in color
; choice of fonts (0=stroke, 1=raster) is in font
;
; OUTPUT: Just to the screen
;
; REGISTERS USED: None modified
;
; SEGMENTS REFERENCED: Upon entry ES must point to the video RAM at
; 0B8000h and DS must point to the data segment used by the point-plot,
; box-filling, line-drawing and stroke character routines.
;
; ROUTINES CALLED: SCHAR or RCHAR
;
; SPECIAL NOTES: No bounds ;hecking is performed. Unpredictable results
; will occur if the horizontal or vertical magnitude is too large.
;
; ROUTINE TO PRINT A MESSAGE TO THE GRAPHICS SCREEN
;
gmessout proc far
;
; get (x,y) location of message on screen
mov ax,xmess ; get x-coord on screen
mov x0,ax ; for first char
mov ax,ymess ; get y-coord on screen
mov y0,ax ; for first char
cld ; forward direction
;
; main loop through characters of the message
gmessloop:
cld ; forward direction
lodsb ; get the ASCII code
cmp al,0 ; test for end of string
je gmessexit
;
; check for fonts
font0:
cmp font,0 ; use font 0 ?
jne nextchar
call rchar ; plot raster characters
;
nextchar:
mov al,8 ; char cell width
mov cl,xmagn ; times horizontal magnitude
mul cl ; multiply
add x0,ax ; add to location of previous char
;
jmp gmessloop ; loop for next char
;
gmessexit:
ret ; return
;
gmessout endp
;-------------------------gmessout routine ends---------------------------+