geb@cadre.UUCP (07/12/84)
Here are some routines to let you use the video bios calls from c:
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
/*****************************************************************************
* video.h 12 Jul 84 G. Banks *
* *
* Header file for video.c defining the constants *
* *
*****************************************************************************/
#define BLANK 32
#define MONOCHROME 0x18
#define COLOR80 0x10
#define COLOR40 0x08
#define NORMAL 7
#define BLINK 0x80
#define UNDERLINE 1
#define INVERSE 0x70
#define HIGHLIGHT 0x0F
#define HIUNDER 9
/*****************************************************************************
* video.c 12 Jul 84 G. Banks *
* *
* set of video functions to control the screen on ibm/pc compatible using *
* bios calls. Must be linked to assembly of vidbios.asm *
* *
* includes: *
* *
* clrtoeos(a) Clears to end of screen with attribute a *
* readc() Returns the character at the cursor *
* read_attribute() Returns the attribute at the cursor *
* clrtoeol(a) Clears to end of line with attribute a *
* readrow() Returns the row of the cursor *
* readcol() Returns the column of the cursor *
* check_display() Decides what kind of display is being used *
* *
****************************************************************************/
#include <video.h>
int clrtoeos(a) /* clears to end of screen to attribute */
char a;
{
int i;
i = readrow();
clrtoeol(a);
while (i++ < 24) {
gotoxy(0,i);
clrtoeol(a);
}
}
char readc() /* returns the char on screen at the current cursor position */
{
return(vreadc()%256);
}
char read_attribute() /* returns attribute at the current cursor position */
{
return(vreadc()/256);
}
int clrtoeol(a) /*clears to the end of the line to attribute */
char a;
{
writenca(BLANK,a,80-readcol());
}
int readrow() /* returns the row of the current cursor position */
{
return(vreadcur()/256);
}
int readcol() /* returns the column of the current cursor position */
{
return(vreadcur()%256);
}
int check_display() /* returns the number of the type of display */
{
return(equip() & 0x18);
}
int num_drives() /* returns the number of drives of the system */
{
int eq;
eq = (equip() & 0x60);
if (eq == 0x60) return(4);
if (eq == 0x40) return(3);
if (eq == 0x20) return(2);
else return(0);
}
; vidbios.asm 12 Jul 84 G. Banks
;
; Set of routines for performing screen operations on ibm pc compatibles
; Using BIOS functions.
;
; Includes:
;
; equip() Determines equipment (monochrome, etc.)
; cls(a) Clears screen to (a = attribute)
; gotoxy(col,row) Cursor addressing
; vreadcur() Returns cursor position
; vreadc() Returns character at current cursor
; writeca(c,a) Writes char c with attrib a at cursor
; writenca(c,a,n) Writes char with attr n times
; writec(c) Writes char with current attribute
INCLUDE MODEL.H ; these are for c86
INCLUDE PROLOGUE.H ; if you don't have them, e.g. lattice,
; they simply define the segment registers, etc.
; as shown in your manual
BDOSINT EQU 21h
VBIOSINT EQU 10h
EQUIPINT EQU 11h
NUMROWS EQU 25
NUMCOLS EQU 80
PUBLIC EQUIP,CLS,GOTOXY,VREADCUR,VREADC,WRITECA,WRITENCA,WRITEC
;int equip()
;
;returns an integer which can be bitwise analysed to determine
;what equipment is being used with the computer.
EQUIP PROC NEAR
int EQUIPINT ;returns equipment attached in AX
ret
EQUIP ENDP
;cls(a)
;char a;
;
;clears the display to blanks of attribute a
CLS PROC NEAR
push bp
push es
mov bp,sp
cli ;don't bother me while I'm on the stack
add sp,6 ;get the argument pointer
pop bx ;get the attribute
mov sp,bp
sti
mov ah,6 ;scroll up
mov al,0 ;blanks
mov ch,0 ;top row
mov cl,0 ;left column
mov dh,NUMROWS-1
mov dl,NUMCOLS-1
mov bh,bl ;blank line attribute
int VBIOSINT ;go do it
pop es
pop bp
ret
CLS ENDP
;gotoxy(x,y)
;int x,y;
;
;cursor addressing through bios
;
GOTOXY PROC NEAR
push bp
push es
mov bp,sp
cli ;don't bother me while I'm on the stack
add sp,6 ;get the argument pointer
pop dx ;column
pop cx ;row
mov sp,bp
sti
mov dh,cl ;get row into dh (column is already in dl)
mov bh,0 ;zero page
mov ah,2 ;setcursor function
int VBIOSINT ;go do it
pop es
pop bp
ret
GOTOXY ENDP
;int vreadcur()
;
;reads the cursor position and returns:
; row = vreadcur() / 256;
; col = vreadcur() % 256;
VREADCUR PROC NEAR
mov bh,0 ;zero page
mov ah,3 ;readcursor function
int VBIOSINT ;go do it
mov ax,dx ;transfer returned row,column values to a reg
ret
VREADCUR ENDP
;int vreadc()
;
;reads the character and attribute at the current cursor position
;
; char = vreadc() % 256;
; attr = vreadc() / 256;
VREADC PROC NEAR
mov bh,0 ;zero page
mov ah,8 ;read character
int VBIOSINT ;go do it
ret
VREADC ENDP
;writeca(a,c)
;char a,c;
;
;writes a character (c) with attribute (a) to the screen
WRITECA PROC NEAR
push bp
push es
mov bp,sp
cli
add sp,6 ;get arguments
pop ax ;character in low byte
pop bx ;attribute in low byte
mov sp,bp
sti
mov bh,0 ;zero page
mov ah,9 ;write character
mov cl,1 ;write it only once
int VBIOSINT ;go do it
pop es
pop bp
ret
WRITECA ENDP
;writenca(a,c,n)
;char a,c,n;
;
;writes a character (c) with attribute (a) to the screen (n) times
WRITENCA PROC NEAR
push bp
push es
mov bp,sp
cli
add sp,6 ;get arguments
pop ax ;character in low byte
pop bx ;attribute in low byte
pop cx ;number of times to write it
mov sp,bp
sti
mov bh,0 ;zero page
mov ah,9 ;write character
int VBIOSINT ;go do it
pop es
pop bp
ret
WRITENCA ENDP
;writec(c)
;char c;
;
;write character at current cursor position
WRITEC PROC NEAR
push bp
push es
mov bp,sp
cli
add sp,6
pop ax
mov sp,bp
sti
mov ah,9 ;write character
mov cx,1 ;write it only once
mov bh,0 ;zero page
int VBIOSINT ;go to it, boy
pop es
pop bp
ret
WRITEC ENDP
@CODE ENDS
END