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Assembly Source File | 1988-03-20 | 23.4 KB | 598 lines

TITLE MPU/MIDI primitives for Modular Sequencer NAME MBM .SALL ;============================================================== ; MusicBox Modular Sequencer, Version 2 ; midi and clock interface ;-------------------------------------------------------------- ; author: John Dunn ; date: 03/07/86 ; update: 03/20/88 ;-------------------------------------------------------------- ; COPYRIGHT (C) 1986 John Dunn, All Rights Reserved ; Entered into the Public Domain, March 20, 1988 ; ; Use and copying of this software and preparation of derivative works ; based upon this software are permitted. Any distribution of this ; software or derivative works must comply with all applicable United ; States export control laws. ; ; This software is made available AS IS, and the author makes no warranty ; about the software, its performance, or its conformity to any specification. ; ; Any person obtaining a copy of this software is requested to send their ; name and address address to: ; ; John Dunn, Senior Research Fellow ; Time Arts Inc. ; 3436 Mendocino Ave. ; Santa Rosa, CA 95401 ; ;============================================================== include order.asm ;-------------------------------------------------------------- include equates.asm ;============================================================== _DATA SEGMENT ASSUME DS:DGROUP, CS:_TEXT ;-------------------------------------------------------------- public midip ;-------------------------------------------------------------- extrn midiok:byte ;-------------------------------------------------------------- moboix0 dw 0 ; MIDI Out Buffer Index mobiix0 dw 0 ; MIDI In Buffer Index ;-------------------------------------------------------------- moboix1 dw 0 ; MIDI Out Buffer Index mobiix1 dw 0 ; MIDI In Buffer Index ;-------------------------------------------------------------- midip db 0 ; midi port number 0/1 mpuis db 0 ; nz if mpu intes happening savint0 db 0 ; saved int byte from 8259A ;-------------------------------------------------------------- _DATA ENDS ;============================================================== _TEXT SEGMENT ASSUME CS: _TEXT, DS: DGROUP, SS: DGROUP, ES: NOTHING ;============================================================== extrn _dummy:far extrn loops:word ;============================================================== ; basic midi port routines ;-------------------------------------------------------------- ; words declared in the CS for faster interrupt service public midixs,mstop,mstart,mcont,midata,miflag,midatix,misend public _mpuinf,_mpuinm ;-------------------------------------------------------------- midixs db 0 ; midi extrnal sync tick mstop db 0 ; midi stop tick mstart db 0 ; midi start tick mcont db 0 ; midi continue tick midata db 0 ; midi input data byte miflag db 0 ; midi input data flag misysx db 0 ; midi sys exclusive flag midatix db 0 ; midi data index misend db 0 ; midi send data flag _mpuinf db 0 ; mpu input from 1=1, 2=2, 0=none _mpuinm db 3 ; mpu input mask nottrue db 'install patch area',0,1,3,7,0 mobuf1 db 8192+105 dup(?) ; MIDI Out Buffer mobuf0 db 8192+128 dup(?) ; MIDI Out Buffer ;-------------------------------------------------------------- ; initialize mpu, int vectors, etc. ; must be called once only on startup ; sets direct MIDI mode, with interrupt on input ; sets interrupt vector 0AH at 0000:0028, for ; hardware interrupt 2. ; public startm startm proc near test mpuis,1 ; already done it? jnz initmx ; yes, split push es ; save current es mov ah,35h ; get current int 2 mov al,0AH int 21H mov word ptr cs:orgint+3,es ; save it mov word ptr cs:orgint+1,bx pop es ; restore es push ds ; save current ds mov ah,25H ; set int vect mov al,0AH ; int 2 for MPU mov dx,offset mpuint mov cx,seg mpuint mov ds,cx int 21H ; set new int vect pop ds ; restore ds cli call mpurst ; reset mpu in al,21H ; enable irq2 mov savint0,al ; save it and al,0FBH out 21H,al mov mpuis,1 ; flag = active sti initmx: ret startm endp ; end of init mpu ;-------------------------------------------------------------- ; shutdown mpu, restore int vectors, etc. ; must be called once only on exit ; public stopm stopm proc near test mpuis,1 ; already done it? jz exitmx ; yes, split cli mov al,0FFH ; issue mpu reset mov dx,mpucmd out dx,al add dx,2 ; do 2nd port out dx,al mov al,savint0 ; get original irq masks out 21H,al ; restore them mov mpuis,0 ; flag = inactive ; push ds mov ah,25h ; restore previous irq2 mov al,0AH mov dx,word ptr cs:orgint+1 mov cx,word ptr cs:orgint+3 mov ds,cx int 21h pop ds ; exitmx: ret stopm endp ;-------------------------------------------------------------- ; this routine is only called by int 2 ; if it was not generated by the mpu, it vectors ; to the original int address, otherwise it saves ; registers, then calls the c routine _mpuint, ; after which it restores registers, clears nmi ; and returns from int. ; mpuint proc far cli ; disable interupts push ax ; save ax push dx mov ah,1 ; set mpu in flag to mpu#1 mov dx,mpstat ; read mpu status in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch add dx,2 ; no, check other port mov ah,2 ; set mpu in flag to mpu#1 in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch mov ah,1 ; set mpu in flag to mpu#1 mov dx,mpstat ; read mpu status in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch add dx,2 ; no, check other port mov ah,2 ; set mpu in flag to mpu#1 in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch mov ah,1 ; set mpu in flag to mpu#1 mov dx,mpstat ; read mpu status in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch add dx,2 ; no, check other port mov ah,2 ; set mpu in flag to mpu#1 in al,dx and al,mpdsr ; generated by mpu? jz mpui1 ; yes, branch mov al,20H out 20H,al pop dx ; restore cpu pop ax sti ; enable interupts iret orgint: jmp far ptr _dummy ; dummy vector, filled by _initm mpui1: push bx ; save cpu state push cx push di push si push bp push ds push es mov cx,cs ; set up seg regs mov ds,cx dec dx ; get mpu int data in al,dx ; / mov _mpuinf,ah ; save flag status test ah,_mpuinm ; check against mask jz mpuiz ; exit if masked out cmp al,0feh ; Active Sensing jz mpuiz ; yes, exit cmp al,0f8H ; Midi Sync? jnz mpui2 ; no, branch inc midixs ; yes, inc the flag jmp short mpuiz ; .. and on to work mpui2: cmp al,0fah ; Midi Start? jnz mpui3 ; no, branch inc mstart ; yes, inc the flag jmp short mpuiz ; .. and on to work mpui3: cmp al,0fbh ; Midi Continue jnz mpui4 ; no, branch inc mcont ; yes, inc the flag jmp short mpuiz ; .. and on to work mpui4: cmp al,0fch ; Midi stop? jnz mpui5 ; no, branch inc mstop ; yes, inc the flag jmp short mpuiz ; .. and on to work mpui5: mov midata,al ; put the data byte away mov miflag,1 ; set the data-in flag cmp al,0f0h ; system exclusive jnz mpui6 ; no, branch mov misysx,1 ; yes, set the flag jmp short mpuiz ; exit mpui6: cmp al,0f7h ; EOX? jnz mpui7 ; no, branch mov misysx,0 ; yes, clear the flag jmp short mpuiz ; exit mpui7: test misysx,-1 ; sys exclusive happening? jnz mpuiz ; yes, branch test misend,-1 ; want to send data? jz mpui8 ; no, branch mov dx,seg bufsp ; yes get the buffer mov es,dx ; / mov bl,midatix ; get the index mov bh,0FH ; put in bank "F" mov es:[bx],al ; put the byte away mpui8: inc midatix ; inc the index mpuiz: ; pop es ; restore seg regs pop ds pop bp ; restore cpu state pop si pop di pop cx pop bx pop dx mov al,20H out 20H,al pop ax sti ; enable interrupts iret ; return from interrupt mpuint endp ;-------------------------------------------------------------- ; mpurst ; clear out the mpu, and set for direct MIDI i/o ; public mpurst mpurst proc near cli ; disable intes mov dx,mpdata ; read mpu data port in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait mov dx,mpstat ; mpu status port mpurs1: in al,dx ; get the status and al,mpdrr ; test for Data Recieve Ready jnz mpurs1 ; loop til ready mov ax,03FH ; MPU UART command out dx,al ; send to mpu mov cx,800H ; delay mpurs2: loop mpurs2 ; / mov dx,mpdata ; read mpu data port in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data ; ; do 2nd MPU ; test midiok,2 ; 2nd MPU online? jz mpursx ; no, just exit ; mov dx,mpdata+2 ; read mpu data port in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data jmp short $+2 ; wait mov dx,mpstat+2 ; mpu status port mpurs3: in al,dx ; get the status and al,mpdrr ; test for Data Recieve Ready jnz mpurs3 ; loop til ready mov ax,03FH ; MPU UART command out dx,al ; send to mpu mov cx,800H ; delay mpurs4: loop mpurs4 ; / mov dx,mpdata+2 ; read mpu data port in al,dx ; get the data jmp short $+2 ; wait in al,dx ; get the data ; mpursx: sti ; enable interrupts ret ; exit mpurst endp ;-------------------------------------------------------------- ; send a byte in AL to MIDI Out Buffer ; public tomidi tomidi proc near test midip,10H ; test midi port jnz tomidi1 ; branch if port 1 ; mov bx,mobiix0 ; get midi out buffer out index mov cs:mobuf0[bx],al; put next byte inc bx ; bump index and bx,8191 ; wrap-around mov mobiix0,bx ; store new mob out index ret ; tomidi1:mov bx,mobiix1 ; get midi out buffer out index mov cs:mobuf1[bx],al; put next byte inc bx ; bump index and bx,8191 ; wrap-around mov mobiix1,bx ; store new mob out index ret tomidi endp ;-------------------------------------------------------------- ; send a byte in AL to all MIDI Out Buffers ; public allmidi allmidi proc near ; mov bx,mobiix0 ; get midi out buffer out index mov cs:mobuf0[bx],al; put next byte inc bx ; bump index and bx,8191 ; wrap-around mov mobiix0,bx ; store new mob out index ; mov bx,mobiix1 ; get midi out buffer out index mov cs:mobuf1[bx],al; put next byte inc bx ; bump index and bx,8191 ; wrap-around mov mobiix1,bx ; store new mob out index ret allmidi endp ;-------------------------------------------------------------- ; get next byte from pass buffer and send to midi ; does nothing if midi output port is busy ; or if the buffer is empty ; public sendm sendm proc near mov bx,moboix0 ; get midi out buffer out index cmp bx,mobiix0 ; same as midi out buffer in index? jz sendm1 ; yes, exit ; test midiok,1 ; ok to do it? jz sendm2 ; no, then fake it ; mov dx,mpstat ; mpu status port in al,dx ; get the status and al,mpdrr ; test for Data Recieve Ready jnz sendm1 ; exit if midi out port is busy ; mov al,cs:mobuf0[bx]; get next byte mov dx,mpdata ; mpu data port out dx,al ; send to mpu sendm2: inc bx ; bump index and bx,8191 ; wrap-around mov moboix0,bx ; store new mob out index ; ; do 2nd buffer ; sendm1: mov bx,moboix1 ; get midi out buffer out index cmp bx,mobiix1 ; same as midi out buffer in index? jz sendm3 ; yes, exit ; test midiok,2 ; ok to do it? jz sendm4 ; no, then fake it ; mov dx,mpstat+2 ; mpu status port in al,dx ; get the status and al,mpdrr ; test for Data Recieve Ready jnz sendm3 ; exit if midi out port is busy ; mov al,cs:mobuf1[bx]; get next byte mov dx,mpdata+2 ; mpu data port out dx,al ; send to mpu sendm4: inc bx ; bump index and bx,8191 ; wrap-around mov moboix1,bx ; store new mob out index sendm3: ret sendm endp ;-------------------------------------------------------------- ; Clear all MIDI channels ; public allclr allclr proc near allclr1:mov midip,0 ; set midi port 0 call sendm ; now really do it allclr2:mov midip,10H ; set midi port 1 call sendm ; now really do it mov bx,moboix0 ; get midi out buffer out index cmp bx,mobiix0 ; same as midi in buffer in index? jnz allclr1 ; no, keep sending mov bx,moboix1 ; get midi out buffer out index cmp bx,mobiix1 ; same as midi in buffer in index? jnz allclr2 ; no, keep sending ret allclr endp ;-------------------------------------------------------------- ; test for midi output buffers empty ; returns al bits 0,1 set if buffers are not empty ; public tstmob tstmob: xor al,al ; clear flag mov bx,moboix0 ; get midi out buffer out index cmp bx,mobiix0 ; same as midi in buffer in index? jz tstmob1 ; yes, branch inc al ; no, set the bit tstmob1:mov bx,moboix1 ; get midi out buffer out index cmp bx,mobiix1 ; same as midi in buffer in index? jz tstmob2 ; yes, branch or al,2 ; no, set the bit tstmob2:ret ; exit w result in AL ;-------------------------------------------------------------- ; Turn off all MIDI modules ; public alloff alloff proc near ; mov dh,0 ; for channels mov cl,dh ; dummy data byte workh1c:mov ah,0B0H ; MIDI Channel message or ah,dh ; add channel info ; mov al,ah ; midi channel msg call allmidi ; / mov al,7CH ; omni off call allmidi ; send mov al,cl ; send dummy call allmidi ; / ; mov al,ah ; midi channel msg call allmidi ; / mov al,7FH ; poly, ano call allmidi ; / mov al,cl ; send dummy call allmidi ; / ; inc dh ; next channel test dh,16 ; 16 channels jz workh1c ; / ; call allclr ; clear the channels ret alloff endp ;-------------------------------------------------------------- ; TIMER ROUTINES ;-------------------------------------------------------------- ; words declared in the CS for faster interrupt service public ticks,ticks1,timer,seconds,secondf ;-------------------------------------------------------------- timeis db 0 ; nz if timer inte is happening times0 dw 0 ; storage for dos timer vector times1 dw 0 ; saa ticks dw 0 ; lsw of tick count ticks1 dw 0 ; msw of tick count timer dw 0 ; system timer count second0 dw 582 ; real time clk ticker seconds dw 0 ; running seconds count secondf db 0 ; nz if seconds was incremented ;-------------------------------------------------------------- ; startt ( sets timer int to vector to dotime ) ; public startt startt proc near test cs:timeis,1 ; already done it? jnz starttx ; yes, split push es mov ah,35H ; get current int 8 mov al,8 ; / int 21H ; / mov cs:times1,es ; save it mov cs:times0,bx pop es ; push ds ; save data seg mov ah,25H ; set int vect mov al,8 ; int 8 for MS timer mov dx,offset dotime; mov cx,seg dotime ; mov ds,cx ; int 21H ; set new int vect pop ds ; restore data seg mov cs:timeis,1 ; flag = active ; cli ; mov ax,00fffh ; set new timing mov ax,007ffh ; set new timing out 40H,al jmp short $+2 mov al,ah out 40H,al sti starttx:ret startt endp ;-------------------------------------------------------------- ; stopt ( restores oringinal dos int ) ; public stopt stopt proc near test cs:timeis,1 ; already done it? jz stoptx ; yes, split push ds ; save current data seg mov ah,25h ; restore previous irq mov al,8 ; / mov dx,cs:times0 ; / mov cx,cs:times1 ; / mov ds,cx ; / int 21h ; / pop ds ; restore data seg mov cs:timeis,0 ; flag = inactive ; cli ; restore original timing mov ax,0ffffh out 40H,al jmp short $+2 mov al,ah out 40H,al sti stoptx: ret stopt endp ;-------------------------------------------------------------- ; DOTIME interrupt routine called every clock tick ; dotime proc far dec cs:second0 ; count down second timer jnz dotim2 ; branch if not time inc cs:seconds ; else bump seconds count mov cs:second0,582 ; 582.4 ticks/sec mov cs:secondf,1 ; set the flag dotim2: test cs:timer,-1 ; timer zero jz dotim1 ; yes, branch dec cs:timer ; no, count down dotim1: inc cs:ticks ; inc ls word jnz dotim0 ; branch if not overflow inc cs:ticks1 ; else inc ms word ;dotim0: test cs:ticks,15 ; bump system stuff every 16th clock dotim0: test cs:ticks,31 ; bump system stuff every 32th clock jz dotimx ; branch if time to doit push ax mov al,20h out 20h,al pop ax iret ; else just return from interrupt dotimx: push cs:times1 ; on to the original inte push cs:times0 ; / ret ; / dotime endp ;-------------------------------------------------------------- _TEXT ENDS END