Category : Assembly Language Source Code
Archive   : RHSTDLIB.ZIP
Filename : GETC.ASM

stdlib segment para public 'slcode'
assume cs:stdlib
;
; Keyboard input routines:
;
;
; InpVector- Points at the current keyboard input routine.
;
GetcAdrs dd sl_GetcStdIn
GetcStkIndx dw 0
GetcStk dd 16 dup (sl_GetcStdIn)
GSIsize = $-GetcStk
;
;
;
public sl_Getc
sl_Getc proc far
jmp dword ptr cs:GetcAdrs
sl_Getc endp
;
;
; SetInAdrs- Stores ES:DI into InpVector which sets the new keyboard vector.
;
public sl_SetInAdrs
sl_SetInAdrs proc far
mov word ptr GetcAdrs, di
mov word ptr GetcAdrs+2, es
ret
sl_SetInAdrs endp
;
;
; GetInAdrs- Returns the address of the current output routine in ES:DI.
;
public sl_GetInAdrs
sl_GetInAdrs proc far
les di, cs:GetcAdrs
ret
sl_GetInAdrs endp
;
;
;
; PushInAdrs- Pushes the current input address onto the input stack
; and then stores the address in es:di into the input address
; pointer. Returns carry clear if no problems. Returns carry
; set if there is an address stack overflow. Does NOT modify
; anything if the stack is full.
;
public sl_PushInAdrs
sl_PushInAdrs proc far
push ax
push di
cmp cs:GetcStkIndx, GSIsize
jae BadPush
mov di, cs:GetcStkIndx
add cs:GetcStkIndx, 4
mov ax, word ptr cs:GetcAdrs
mov word ptr cs:GetcStk[di], ax
mov ax, word ptr cs:GetcAdrs+2
mov word ptr cs:GetcStk+2[di], ax
pop di
mov word ptr cs:GetcAdrs, di
mov word ptr cs:GetcAdrs+2, es
pop ax
clc
ret
;
BadPush: pop di
pop ax
stc
ret
sl_PushInAdrs endp
;
;
; PopInAdrs- Pops an input address off of the stack and stores it into
; the GetcAdrs variable.
;
public sl_PopInAdrs
sl_PopInAdrs proc far
push ax
mov di, cs:GetcStkIndx
sub di, 4
jns GoodPop
;
; If this guy just went negative, set it to zero and push the address
; of the stdout routine onto the stack.
;
xor di, di
mov word ptr cs:GetcStk, offset sl_GetcStdIn
mov word ptr cs:GetcStk+2, seg sl_GetcStdIn
;
GoodPop: mov cs:GetcStkIndx, di
mov es, word ptr GetcAdrs+2
mov ax, word ptr cs:GetcStk+2[di]
mov word ptr cs:GetcAdrs+2, ax
mov ax, word ptr cs:GetcStk[di]
xchg word ptr cs:GetcAdrs, ax
mov di, ax
pop ax
ret
sl_PopInAdrs endp
;
;
;
; GetcBIOS- Reads a character from the keyboard using the BIOS routines.
;
public sl_GetcBIOS
sl_GetcBIOS proc far
mov ah, 0
int 16h
ret
sl_GetcBIOS endp
;
;
;
; GetcStdIn- Reads a character from DOS' standard input.
;
public sl_GetcStdIn
sl_GetcStdIn proc far
mov ah, 7
int 21h
mov ah, 0
cmp al, 0
jnz DOS_GetcX
;
; If DOS returned zero, get scan code and return in AX
;
mov ah, 7
int 21h
mov ah, al
mov al, 0
DOS_GetcX: ret
sl_GetcStdIn endp
stdlib ends
end