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|
;
page 60,132
;
title CP/DOS DosFreeSeg mapper
;
dosxxx segment byte public 'dos'
assume cs:dosxxx,ds:nothing,es:nothing,ss:nothing
;
; ************************************************************************* *
; *
; * MODULE: DosFreeSeg
; *
; * FILE NAME: dos023.asm
; *
; * FUNCTION: This module deallocates a segment
; *
; *
; * CALLING SEQUENCE:
; *
; * push selector ; selector of the segment
; * call dosfreeseg
; *
; * RETURN SEQUENCE:
; *
; * MODULES CALLED: DOS int 21h, ah=49h
; *
; *************************************************************************
public dosfreeseg
.sall
.xlist
include macros.inc
.list
invalid_selector equ 0006h
str struc
Old_bp dw ?
Return dd ?
Selector dw ? ; selector of the segment to be freed
str ends
dosfreeseg proc far
Enter dosfreeseg ; push registers
mov es,[bp].selector ; get selector in es
mov ah,49h
int 21h ; free memory segment
jc error ; jump if error
sub ax,ax ; zero return code
jmp exit ; go to exit
error: mov ax,invalid_selector ; put in error code
exit: Mexit ; pop registers
ret size str - 6 ; return
dosfreeseg endp
dosxxx ends
end
|
