HAM Radio 1/HamRadio.cdr/misc/hidi/play.asm

Assembly Source File | 1987-03-27 | 4.0 KB | 326 lines

COUNTR    EQU    72 ;16572 HZ

TCADRC    EQU    43H
TCADRD    EQU    40H

TCMODE    EQU    34H
TC2MODE    EQU    0B8H

PPIADR    EQU    61H
NORMPPI    EQU    48H

;-------------------------------------------

STK    SEGMENT    STACK
    DW    128 DUP (0)
STK    ENDS

;-------------------------------------------

CODE    SEGMENT    PARA
    ASSUME    CS:CODE,DS:CODE,SS:STK
    ASSUME    ES:NOTHING

;-------------------------------------------

FILELEN    DW    0
HANDLE    DW    0
MSG2    DB    'Disk error',0DH,0AH,24H

;-------------------------------------------

START:

    CALL    PARSESGL

;set DS and ES

    PUSH    CS
    POP    DS
    PUSH    CS
    POP    ES

;open the file

    MOV    DX,OFFSET PARM
    MOV    AX,3D00H
    INT    21H
    JNC    L1
    JMP    DSKERR
L1:    MOV    HANDLE,AX

;read the file

    PUSH    DS
    MOV    BX,HANDLE
    MOV    AX,HIMEM
    MOV    DS,AX
    ASSUME    DS:NOTHING
    MOV    DX,0
    MOV    CX,0FFFFH
    MOV    AH,3FH
    INT    21H
    POP    DS
    ASSUME    DS:CODE
    JNC    L2
    JMP    DSKERR
L2:    MOV    FILELEN,AX

;close the file

    MOV    BX,HANDLE
    MOV    AH,3EH
    INT    21H

;get vector of timer current timer interrupt

    MOV    AX,3508H
    INT    21H
    MOV    WORD PTR OLDTMRINT,BX
    MOV    WORD PTR OLDTMRINT+2,ES

;mask timer interrupt

    IN    AL,21H
    OR    AL,01H
    OUT    21H,AL

;plug in the local timer interrupt routine

    MOV    DX,OFFSET TIMERINT
    MOV    AX,2508H
    INT    21H

;rev up timer

    MOV    AL,TCMODE
    OUT    TCADRC,AL
    MOV    AX,COUNTR
    OUT    TCADRD,AL
    MOV    AL,AH
    OUT    TCADRD,AL

;set DS

    ASSUME    DS:NOTHING
    MOV    AX,HIMEM
    MOV    DS,AX

;initialize registers

    MOV    BP,0
    MOV    BX,0
    MOV    CH,[BX]
    MOV    AH,0
    MOV    DX,PPIADR

;unmask timer interrupt

    IN    AL,21H
    AND    AL,0FEH
    OUT    21H,AL
    STI

;test for done

TFD:
    OR    BP,BP
    JE    TFD

;mask timer interrupt

    CLI
    IN    AL,21H
    OR    AL,01H
    OUT    21H,AL
    STI

;fix DS

    MOV    AX,CS
    MOV    DS,AX
    ASSUME    DS:CODE

;fix timer

    MOV    AL,TCMODE
    OUT    TCADRC,AL
    MOV    AL,0
    OUT    TCADRD,AL
    OUT    TCADRD,AL

;restore original timer interrupt vector

    PUSH    DS
    LDS    DX,CS:OLDTMRINT
    MOV    AX,2508H
    INT    21H
    POP    DS

;unmask timer interrupt

    IN    AL,21H
    AND    AL,0FEH
    OUT    21H,AL

;figure out how long the system 18.2 Hz
; timer has been off

    MOV    AX,COUNTR
    SHL    AX,1
    SHL    AX,1
    SHL    AX,1
    MOV    CX,FILELEN
    MUL    CX

;adjust the BIOS time of day to catch up

    PUSH    ES
    MOV    AX,40H
    MOV    ES,AX
    MOV    BX,6CH
    CLI
    ADD    ES:[BX],DX
    ADC    WORD PTR ES:[BX+2],0
    CMP    WORD PTR ES:[BX+2],18H
    JB    BIOSFIXED
    JA    WRAP
    CMP    WORD PTR ES:[BX],0B0H
    JB    BIOSFIXED
WRAP:    SUB    WORD PTR ES:[BX],0B0H
    SBB    WORD PTR ES:[BX+2],18H
BIOSFIXED: STI
    POP    ES

;exit

    MOV    AX,4C00H
    INT    21H

;disk error message

DSKERR:
    MOV    AX,CS
    MOV    DS,AX
    MOV    DX,OFFSET MSG2
    MOV    AH,9
    INT    21H
    MOV    AX,4C01H
    INT    21H

;-------------------------------------------

;timer interrupt routine

    ASSUME    DS:NOTHING,ES:NOTHING
    ASSUME    SS:NOTHING

    EVEN

OLDTMRINT DD    0

TIMERINT PROC    FAR

    OR    BP,BP
    JNZ    TMRINT1

    SUB    AL,AL
    RCL    CH,1
    RCL    AL,1
    RCL    AL,1
    OR    AL,NORMPPI
    OUT    DX,AL

    INC    AH
    CMP    AH,8
    JNE    TMRINT1
    SUB    AH,AH

    INC    BX
    MOV    CH,[BX]
    CMP    BX,FILELEN
    JNZ    TMRINT1
    INC    BP

TMRINT1:
    MOV    AL,20H
    OUT    20H,AL
    IRET

TIMERINT ENDP

;-------------------------------------------

PARM    DB    128 DUP (0)

SPECERRMSG    DB    'File specification'
    DB    ' error',0DH,0AH,24H

;it is assumed that DS and ES both point
; to the PSP.

PARSESGL    PROC

    CLD
    MOV    DI,80H
    MOV    CL,[DI]
    SUB    CH,CH
    INC    DI

    CMP    CX,1
    JBE    PARSS4

;find first non-blank character

    MOV    AL,20H
    REPE    SCASB
    JNE    PARSS2
PARSS4:    PUSH    CS
    POP    DS
    MOV    DX,OFFSET SPECERRMSG
    MOV    AH,9
    INT    21H
    MOV    AX,4C01H
    INT    21H

;find next blank character or end

PARSS2:
    DEC    DI
    INC    CX
    MOV    BX,DI
    REPNE    SCASB

;save parameter

    JCXZ    PARSS3
    DEC    DI
PARSS3:    PUSH    CX
    PUSH    DI
    PUSH    ES
    PUSH    CS
    POP    ES
    MOV    CX,DI
    SUB    CX,BX
    MOV    SI,BX
    MOV    DI,OFFSET PARM
    REP    MOVSB
    POP    ES
    POP    DI
    POP    CX

    RET

PARSESGL    ENDP

;-------------------------------------------

CODE    ENDS

;-------------------------------------------

HIMEM    SEGMENT    PARA
HIMEM    ENDS

    END    START