rqbcode.inc

MMURTL(tm) Computer Operating System Ver x0.8, source code.

;   MMURTL Operating System Source Code
;   Copyright 1991,1992,1993, Richard A. Burgess
;   ALL RIGHTS RESERVED
;   Version x0.8
;=============================================================================

NewRQB:
; INPUT : NONE
; OUTPUT : EAX
; REGISTERS : EAX,EBX,FLAGS
; MODIFIES : pFreeRQB
;
; This routine returns to the caller a pointer to the next free RQB.
; The data used in this algorithm is the free jcb pointer (pFreeRQB).
; This routine will return in EAX register the address of the next free jcb.
; If none exists, then EAX will contain NIL (0). This routine will also
; update the value of pFreeRQB to point to the next "unused" RQB in
; the free pool.
;
		MOV EAX,pFreeRQB        ;Get OS pointer to RQBs
		CMP EAX,NIL             ;IF pFreeRQB=NIL THEN Return;
		JE NewRQBDone           ;
		MOV EBX,[EAX.pNextRQB]  ;Get pointer to next free one
		MOV pFreeRQB,EBX        ;Put it in OS pointer
		DEC _nRQBLeft			;
NewRQBDone:
	    RETN                    ;

;=============================================================================

DisposeRQB:
; INPUT : EAX
; OUTPUT : NONE
; REGISTERS : EAX, EBX, FLAGS
; MODIFIES : pFreeRQB
;
; This routine will place the RQB pointed to by EAX back into the free
; pool of RQBs pointed to by (pFreeRQB) if EAX is not NIL.
;
		CMP EAX,NIL             ; If pJQBin = NIL THEN Return;
		JE DispRQBDone          ;
		MOV EBX,pFreeRQB        ;EBX has OS ptr to free list
		MOV [EAX.pNextRQB],EBX  ;Move it into newly freed RQB
		MOV pFreeRQB,EAX        ;Move ptr to newly frred RQB to OS
		INC _nRQBLeft			;
DispRQBDone:
	    RETN                    ;

;========================= End of Module =================================