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Length: 4064 (0xfe0)
Notes: Mikados TextFile, Mikados_K
Names: »REDBAK«
└─⟦38ff28550⟧ Bits:30004682 Pascal Standard Assembler til MIKADOS
└─ ⟦this⟧ »REDBAK«
;*************************************************************
;* PASCAL STANDARD ASSEMBLER PACKAGE. *
;* *
;* (C) 1980 DANSK DATA ELEKTRONIK APS. *
;*************************************************************
;
;*************************************************************
;* PROCEDURE NAME: REDBAK *
;*************************************************************
;
; CT 07-MAY-1980
;
;=============================================================
; DESCRIPTION:
; THIS PURCEDURE IS USED TO READ A SEQUENTIAL MIKADOS FILE
; BACKWARDS.
; PLEASE REFER TO THE PASCAL STANDARD ASSEMBLER PACKAGE MANUAL
; SECTION 8.2 FOR DETAILS.
;
;-------------------------------------------------------------
; STACK CONTENTS ON ENTRY: I I
; I---------------I
; I RETURN ADR. I
; I---------------I
; I -> CONTENTS I
; I---------------I
; I -> FILEID I
; I---------------I
; I I
;-------------------------------------------------------------
; STACK CONTENTS ON EXIT: EMPTY
;=============================================================
SKIP
SYMB
OFFSET:EQU 8C ;THIS IS THE OFFSET FROM FILEID TO THE
; DATA CONTROL BLOCK
REDBAK::
;
;'SHUFFLE' THE STACK SO THAT IT MEETS THE NEED OF THE READB
;SUBROUTINE
;
POP B ;BC=RETURN ADDRESS
POP D ;DE->CONTENTS
POP H ;HL->FILEID
PUSH B
PUSH D
INX D ;DE->CONTENTS(1)
PUSH D
LXI B,OFFSET;COMPUTE THE ADDRESS OF THE
DAD B ; DATA CONTROL BLOCK
PUSH H ;HL->DCB
;THE STACK NOW LOOKS LIKE THIS:
; I I
; I---------------I
; I -> DCB I
; I---------------I
; I ->CONTENTS(1) I
; I---------------I
; I ->CONTENTS(0) I
; I---------------I
; I RETURN ADR. I
; I---------------I
; I I
;
;CLEAR THE END-OF-FILE FLAG (BIT 2 OF THE DFLAG FIELD OF THE
;DCB). IT MAY OF COURSE NOT HAVE BEEN SET, BUT NEVER MIND
;THAT!
;
LXI B,DFLAG
DAD B ;HL->DCB.DFLAG
MOV A,M ;A:=DCB.DFLAG
ANI 0FB ;CLEAR BIT 2
MOV M,A
;
;READ THE RECORD!
;
CALL READB
;
;REG. A NOW CONTAINS A POSSIBLE ERROR CODE
;REG. B CONTAINS THE LENGTH OF THE RECORD, WHICH SHOULD BE
; STORED IN CONTENTS(0)
;
STA IORSLT ;SET IORESULT
POP D ;DE->CONTENTS(0)
MOV A,B ;A:=LENGTH OF RECORD
STAX D ;CONTENTS(0):=LENGTH OF RECORD
RET
END