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;
page 80,132
;0
title CP/DOS DosChgFilePtr mapper * * *
;
dosxxx segment byte public 'dos'
assume cs:dosxxx,ds:nothing,es:nothing,ss:nothing
;**********************************************************************
;*
;* MODULE: doschgfileptr
;*
;* FILE NAME: dos007.asm
;*
;* CALLING SEQUENCE:
;*
;* push word file handle
;* push dword distance
;* push word move type
;* push@ dword new pointer
;* call doschgfileptr
;*
;* MODULES CALLED: PC-DOS Int 21h, ah=42h, move file pointer
;*
;*********************************************************************
public doschgfileptr
.sall
.xlist
include macros.inc
.list
str struc
old_bp dw ?
return dd ?
newptr dd ? ; new file pointer
movtyp dw ? ; move type
dstnce dd ? ; distance to be moved
handle dw ? ; file handle
str ends
doschgfileptr proc far
Enter doschgfileptr ; push registers
push es
les dx,[bp].dstnce
mov cx,es ; set distance
pop es
mov ax,[bp].movtyp ; get move type
mov bx,[bp].handle ; get handle
mov ah,42h
int 21h ; move file pointer
jc exit ; return if error
lds si,[bp].newptr ; set pointer
mov word ptr [si],ax ; save the new pointer
mov word ptr [si]+2,dx ;
sub ax,ax ; set godd return code
exit: mexit ;pop registers
ret size str - 6 ;return
doschgfileptr endp
dosxxx ends
end
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