;*****************************************************************
;                                                                *
;       VIRTUAL   SCREEN   STRUCTURES   AND   EQUATES            *
;                                                                *
;*****************************************************************


backsp             equ   08H
escape             equ   01bH
blank              equ   ' '

crt_col            equ   80                   ; screen sizings
crt_row            equ   24
crt_size           equ   crt_col * crt_row
crtfull            equ   0

                                              ; Screen Structure
vs_cursor          equ   word ptr    0[bx]    ; cursor pts to attrib and char
vs_oldcursor       equ   word ptr    2[bx]
vs_column          equ   byte ptr    4[bx]
vs_row             equ   byte ptr    5[bx]
vs_mode            equ   byte ptr    6[bx]    ; screen mode - see vsm values
vs_attrib          equ   byte ptr    7[bx]
vs_xy              equ   word ptr    8[bx]    ; x-y coordinates for direct
vs_old_xy          equ   word ptr  0aH[bx]    ; cursor positioning
vs_screen_seg      equ   word ptr  0cH[bx]    ; for screen image buffer
vs_escape_rt       equ   word ptr  0eH[bx]    ; escape routine to ret to
vs_struc_len       equ   010h                 ; edge up to pp. boundary

                                              ; attribute bit values
vsa_reverse       equ   01110000B             ; IBM PC compatible
vsa_normal        equ   00000111B
vsa_blink         equ   10000000B
vsa_bright        equ   00001000B

                                              ; mode bit values
vsm_no_wrap       equ   00000010B             ; CCP/M only
vsm_nocursor      equ   00000100B

vccb_pcon         equ   0ah
vccb_vcon         equ   0bh
