CD-X 1/cdx_01.iso/demodisc/basq/source/poweru/overlay.asm

Assembly Source File | 1993-08-16 | 4.0 KB | 238 lines

PUBLIC        OPENOVERLAY
PUBLIC        LOADOVERLAYITEM
PUBLIC        WRITOVERLAYITEM
PUBLIC        CLOSEOVERLAY
PUBLIC        OILENGTH

.386
.MODEL USE16 SMALL
.DATA

OVERLAYMODULEBA    DD    0
OVERLAYLSIGN    DB    5 DUP(0)
OVERLAYBSIGN    DB    'PSO10'
OVERLAYHANDLE    DW    0
OVERLAYOPENED    DB    0
OVERLAYOPENEDH    DB    0
OVERLAYENDPOS    DD    -9
OIID        DW    0
OIUID        DW    0
OIPOS        DD    0
OILENGTH    DD    0
OIWLENGTH    DD    0
OISEG        DW    0
OIPID        DW    0

.CODE

OPENOVERLAY:    PUSHA
        PUSH    DS
        PUSH    ES
        MOV    AX,SEG OVERLAYMODULEBA
        MOV     DS,AX
        MOV    OVERLAYOPENED,0
        MOV    OVERLAYOPENEDH,1
        MOV    AX,CS
        SUB    AX,10H
        MOV    DS,AX
        MOV    SI,2CH
        MOV    AX,[SI]
        MOV    DS,AX
        MOV    ES,AX
        XOR    DI,DI
        MOV    AL,1
        MOV    CX,0FFFH
        CLD
        REPNZ    SCASB
        INC    DI
        MOV    DX,DI
        MOV    AH,3DH
        MOV    AL,01000010B
        INT    21H
        JC    SHORT NOTOPENOKOV
        MOV    BX,SEG OVERLAYMODULEBA
        MOV    DS,BX
        MOV    OVERLAYHANDLE,AX
        MOV    OVERLAYOPENEDH,1
        MOV    BX,AX
        MOV    AH,42H
        MOV    AL,2
        MOV    CX, WORD PTR OVERLAYENDPOS[2]
        MOV    DX, WORD PTR OVERLAYENDPOS[0]
        INT    21H
        JC    SHORT NOTOPENOKOV
        MOV    AH,3FH
        MOV    CX,9
        MOV    BX,OVERLAYHANDLE
        LEA    DX,OVERLAYMODULEBA
        INT    21H
        JC    SHORT NOTOPENOKOV
        CLD
        MOV    AX,DS
        MOV    ES,AX
        MOV    CX,5
        LEA    SI,OVERLAYBSIGN
        LEA    DI,OVERLAYLSIGN
        REPZ    CMPSB
        OR    CX,CX
        JNZ    SHORT SCFLAG
        CLC
        MOV    OVERLAYOPENED,1
NOTOPENOKOV:    POP    ES
        POP    DS
        POPA
        RET
SCFLAG:        STC
        JMP    NOTOPENOKOV

LOADOVERLAYITEM:PUSHAD
        PUSH    DS
        PUSH    SEG OIID
        POP    DS
        OR    OVERLAYOPENED,0
        JNZ    SHORT OPENEDOV
        STC
        JMP    ENDLOADING
OPENEDOV:    MOV    OIPID,BX
        MOV    OISEG,AX
        MOV    SI,BX
        MOV    AX,4200H
        MOV    BX,OVERLAYHANDLE
        MOV    CX,WORD PTR OVERLAYMODULEBA[2]
        MOV    DX,WORD PTR OVERLAYMODULEBA[0]
        INT    21H
        JC    ENDLOADING
NEXTITEM:    MOV    AH,3FH
        MOV    BX,OVERLAYHANDLE
        MOV    CX,12
        LEA    DX,OIID
        INT    21H
        JC    SHORT ENDLOADING
        OR    OIID,0
        JNZ    SHORT GOMORE
        STC
        JMP    ENDLOADING
GOMORE:        CMP    SI,OIUID
        JNZ    SHORT NEXTITEM
        MOV    AX,4200H
        MOV    BX,OVERLAYHANDLE
        MOV    CX,WORD PTR OIPOS[2]
        MOV    DX,WORD PTR OIPOS[0]
        INT    21H
        JC    SHORT ENDLOADING
        MOV    ESI,OILENGTH
        MOV    EDI,32000
        CMP    ESI,32000
        JAE    SHORT NONEWVALUEEDI
        MOV    EDI,ESI
NONEWVALUEEDI:    XOR    DX,DX
RETRYLOADING:    MOV    AX,3F00H
        MOV    BX,OVERLAYHANDLE
        MOV    CX,DI
        PUSH    DS
        PUSH    OISEG
        POP    DS
        INT    21H
        POP    DS
        JC    SHORT ENDLOADING
        SUB    ESI,EDI
        OR    ESI,ESI
        JNZ    SHORT NOENDLOADING
        CLC
        JMP    ENDLOADING
NOENDLOADING:    ADD    DX,DI
        JNC    SHORT NOADDSEG
        ADD    OISEG,2000
NOADDSEG:    CMP    ESI,32000
        JAE    SHORT NONEWEDI
        MOV    EDI,ESI
NONEWEDI:    JMP    RETRYLOADING
ENDLOADING:    POP    DS
        POPAD
        RET

WRITOVERLAYITEM:PUSHAD
        PUSH    DS
        PUSH    SEG OIID
        POP    DS
        OR    OVERLAYOPENED,0
        JNZ    SHORT OPENEDOV2
        STC
        JMP    ENDLOADING2
OPENEDOV2:    MOV    OIPID,BX
        MOV    OISEG,AX
        MOV    OIWLENGTH,ECX
        MOV    SI,AX
        MOV    AX,4200H
        MOV    BX,OVERLAYHANDLE
        MOV    CX,WORD PTR OVERLAYMODULEBA[2]
        MOV    DX,WORD PTR OVERLAYMODULEBA[0]
        INT    21H
        JC    ENDLOADING2
NEXTITEM2:    MOV     AH,3FH
        MOV    BX,OVERLAYHANDLE
        MOV    CX,12
        LEA    DX,OIID
        INT    21H
        JC    ENDLOADING2
        OR    OIID,0
        JNZ    SHORT GOMORE2
        STC
        JMP    ENDLOADING2
GOMORE2:    CMP    SI,OIUID
        JNZ    SHORT NEXTITEM2
        MOV    AX,4200H
        MOV    BX,OVERLAYHANDLE
        MOV    CX,WORD PTR OIPOS[2]
        MOV    DX,WORD PTR OIPOS[0]
        INT    21H
        JC    SHORT ENDLOADING2
        MOV    ESI,OIWLENGTH
        CMP    ESI,OILENGTH
        JBE    SHORT OVLENGTHOK
        MOV    ESI,OILENGTH
OVLENGTHOK:    MOV    EDI,32000
        CMP    ESI,32000
        JAE    SHORT NONEWVALUEEDI2
        MOV    EDI,ESI
NONEWVALUEEDI2:    XOR    DX,DX
RETRYLOADING2:    MOV    AX,4000h
        MOV    BX,OVERLAYHANDLE
        MOV    CX,DI
        PUSH    DS
        PUSH    OISEG
        POP    DS
        INT    21H
        POP    DS
        JC    SHORT ENDLOADING2
        SUB    ESI,EDI
        OR    ESI,ESI
        JNZ    SHORT NOENDLOADING2
        CLC
        JMP    ENDLOADING2
NOENDLOADING2:    ADD    DX,DI
        JNC    SHORT NOADDSEG2
        ADD    OISEG,2000
NOADDSEG2:    CMP    ESI,32000
        JAE    SHORT NONEWEDI2
        MOV    EDI,ESI
NONEWEDI2:    JMP    RETRYLOADING2
ENDLOADING2:    POP    DS
        POPAD
        RET

CLOSEOVERLAY:    PUSHA
        PUSH    DS
        MOV    AX,SEG OVERLAYMODULEBA
        MOV    DS,AX
        CMP    OVERLAYOPENEDH,1
        JNZ    SHORT NOTOPENEDOV
        MOV    AH,3EH
        MOV    BX,OVERLAYHANDLE
        INT    21H
NOTOPENEDOV:    POP    DS
        POPA
        RET

END