; Settings for TASM LOCALS @@ JUMPS .8086 ; Ensure that only 8086 assembly code is used ; Timing settings: IRQrate = 60 PITdivider = 19886 ; 1234DCh / IRQrate ; Handy macros word0 equ (word ptr 0) word2 equ (word ptr 2) word4 equ (word ptr 4) ;;;;;;;;;;;; ;;;;;;;;;;;; text SEGMENT PARA PUBLIC main: ASSUME CS:text,DS:nothing,ES:nothing xor ax, ax mov ds, ax ; Load the old INT 08 vector ; and install our own cli mov ax, OFFSET NewI08 mov dx, cs ;SEG NewI08 xchg ax, [ds:8*4].word0 xchg dx, [ds:8*4].word2 mov OldI08.word0, ax mov OldI08.word2, dx ; Configure the PIT to ; issue IRQ at 60 Hz rate mov ax, PITdivider call SetupPIT sti mov ax, data mov ds, ax ASSUME DS:data mov [psp], es ; ^save program segment prefix, for it will be ; used for locating the commandline parameters call PlayerMain ; Silence each channel mov di, 300h @@1:mov cx, di xor ax, ax call SetupAudio sub di, 100h jns @@1 cli ; Reset PIT to defaults (~18.2 Hz) mov ax, 0 ; actually means 10000h call SetupPIT ; Restore the old INT 08 vector xor ax, ax mov ds, ax les si, [OldI08] mov [ds:8*4].word0, si mov [ds:8*4].word2, es sti ; Terminate program mov ax, 4C00h int 21h ; INT 21, AH=4Ch, AL=exit code ;;;;;;;;;;;; PlayerMain: ASSUME CS:text, DS:data, ES:nothing ; Save the stack pointer for this call frame. ; DosErrorQuit restores it if an error happens. mov [songsp], sp ; Find the commandline parameter that contains ; the name of the file we want to play mov dx, 1 call GetParamStr ; Exit if filename was not given mov dx, OFFSET UsageMsg test ax, ax jz PrintMessage ; Save filename mov FileNamePtr.word0, si mov FileNamePtr.word2, es mov FileNameLength, ax ; Prepare to address the file buffer mov ax, buffers mov es, ax ASSUME ES:buffers ; Try to open the file call SongFileOpen ; Set 40x25 color text mode mov ax, 1 int 10h ; Print message mov dx, OFFSET PlayingMsg0 call PrintMessage push ds lds dx, FileNamePtr call PrintMessage pop ds mov dx, OFFSET PlayingMsg1 call PrintMessage ; Main loop @@mainloop: hlt ; wait for IRQ ; Check it was timer IRQ mov al, 0 lock xchg al, [IRQticked] test al, al jz @@2 ; It was; advance the song. call SongTick call SongVisualize @@2: ; Loop until some input is given mov ah, 1 int 16h ; INT 16,AH=1, OUT:ZF=status jz @@mainloop ; Close input file call SongFileClose ; Read the input key xor ax, ax int 16h ; INT 16,AH=0, OUT:AX=key ret DosErrorQuit: mov sp, [songsp] ; ^Restore stack pointer to what was saved ; in PlayerMain. This, because error might ; have happened within a function call chain. ; It is our cheap equivalent of C++ "throw". xchg ax, bp ; save error code mov dx, OFFSET ErrorPart0 call PrintMessage ; print part0 push ds lds dx, FileNamePtr call PrintMessage ; print filename pop ds mov dx, OFFSET ErrorPart1 call PrintMessage ; print part1 test bp, bp ; analyze error code jns @@2 and bp, 7FFFh ; hardcoded error message mov dx, bp jmp @@1 @@2:cmp bp, 2 mov dx, OFFSET DOSerror2 je @@1 cmp bp, 3 mov dx, OFFSET DOSerror3 je @@1 cmp bp, 4 mov dx, OFFSET DOSerror4 je @@1 cmp bp, 5 mov dx, OFFSET DOSerror5 je @@1 mov dx, OFFSET UnprintableErr @@1:call PrintMessage ; print error message mov dx, OFFSET ErrorPart2 ;jmp PrintMessage ; print part2 PrintMessage: mov ah, 9 int 21h ;^ INT 21, AH=9, DS:DX=Address ; of $-terminated message ret ;;;;;;;;;;;;;;;;;;;;;;;; ; SONG PARSER & PLAYER ; ;;;;;;;;;;;;;;;;;;;;;;;; SongTick: cmp [pending], 0 jz @@read_event inc [pending] ; approach zero ret @@n:call SongFileReadByte neg al ; -n @@1:mov [pending], al ; -1 jmp SongTick @@c:; ignore the channel setup call SongFileReadWord jmp @@read_event @@p:; ignore the pcm data call SongFileReadByte call SongFileReadWord @@r:jz @@read_event call SongFileReadByte dec di jmp @@r @@read_event: call SongFileReadByte cmp al, 0FFh ; submit row 1 times jz @@1 cmp al, 0FDh ; submit row N times jz @@n cmp al, 0FEh ; setup channel type jz @@c cmp al, 0FBh ; setup PCM sample jz @@p cmp al, 20h jb @@default_event ; Alter channel ; Alter square wave (Ver3 only) ; AL.high4 = duty (2,4,8,12), ignored ; AL.low4 = volume (0-15) push ax ; Read channel number and the wave length call SongFileReadByte ;Read channel push ax call SongFileReadWord ;Read wavelen pop cx pop ax jmp @@skip_ver1_fixes @@default_event: ; AL = channel push ax call SongFileReadWord ;Read wavelen call SongFileReadByte ;Read volume pop cx cmp [fileversion], 1 jne @@skip_ver1_fixes ; For SND version 1, wavelen ; is actually a frequency, ; and volume is 0..255 shr al, 4 ; divide by 16 -> 0..15 ; Calculate wavelen: 110000 / freq. push ax mov dx, 1 ; 110000 >> 16 mov ax, 44464 ; 110000 & 0FFFFh cmp di, 2 ; Ensure that the quotient will jae @@2 ; not be too large to fit in a mov di, 2 ; 16-bit register (overflow) @@2: div di xchg ax, di pop ax @@skip_ver1_fixes: cmp cl, 4 ; Check channel is 0-3 jae @@read_event and al, 0Fh mov dx, di mov ch, cl call SetupAudio jmp @@read_event ;;;;;;;;;;;;;;;;; ; SONG FILE I/O ; ;;;;;;;;;;;;;;;;; SongFileOpen: push ds mov bx, FileNameLength lds si, FileNamePtr ; ^ Load Length before Ptr, because ; "lds" overwrites ds which is needed ; for accessing variables mov dx, si ; Put nul-terminator into filename mov byte ptr [bx+si], 0 mov ax, 3D00h ; Open in read-only mode int 21h ;^ INT 21, AH=3Dh, AL=access mode, ; DS:DX=address of 0-terminated filename string ; Now change the trailing 0 to '$' ; so the filename can be printed. mov byte ptr [bx+si], '$' pop ds jc DosErrorQuit mov [songfd], ax ; Save file handle ; Read SND file header mov dx, OFFSET songhdr mov cx, 16 call SongFileRawRead ; Verify header validicity mov ax, OFFSET Error_Fmt + 8000h cmp signature.word0, 4E53h ; 'SN' jne DosErrorQuit cmp signature.word2, 1A44h ; 'D^Z' jne DosErrorQuit ;cmp rate, IRQrate ;jne DosErrorQuit cmp channelcount, 0 ; Zero channels is an error. je DosErrorQuit cmp channelcount, 5 ; >5 channels: also an error. ja DosErrorQuit cmp fileversion, 1 ; Format: iNES je @@1 cmp fileversion, 3 ; Format: nezplay jne DosErrorQuit @@1: ret SongFileClose: mov bx, [songfd] mov ah, 3Eh int 21h ; INT 21, AH=3Eh, BX=handle ret SongFileRawRead: ; DX = target, CX = byte count ; Uses: AX, BX push ds mov bx, [songfd] mov ax, SEG filebuffer mov ds, ax mov ah, 3Fh int 21h ;^ INT 21h, AH=3Fh ; CX=number of bytes, DS:DX=buffer pop ds jc DosErrorQuit ret SongFileFillBuffer: mov dx, OFFSET filebuffer mov cx, filebuf_size call SongFileRawRead mov [bufreadpos], 0 mov [bufsize], ax test ax, ax mov ax, OFFSET EndOfFile + 8000h jz DosErrorQuit SongFileReadByte: ; OUT: AX = byte ; Uses: BX, CX, DX mov bx, [bufreadpos] cmp bx, [bufsize] jae SongFileFillBuffer mov ah, 0 mov al, filebuffer[bx] inc bx mov [bufreadpos], bx ret SongFileReadWord: ; Out: DI = word ; Uses: AX, BX, CX, DX call SongFileReadByte xchg ax, di call SongFileReadByte xchg ah, al or di, ax ret ;;;;;;;;;;;;;;;;; ; VISUALIZATION ; ;;;;;;;;;;;;;;;;; SongVisualize: push es les di, dword ptr [VisMem] ; Loop through each channel. ; Each is represented by a column ; that is 10 characters wide. mov si, 0 @@5: mov bx, si mov bp, ch_delta[si+bx] or bp, bp jz @@4a mov bp, 2 ;number of spaces before js @@4 mov bp, -1 @@4a:inc bp @@4: mov ax, ch_period[si+bx] call @@translate_period mov cl, ch_volume[si] mov ch, 0 sub cx, 16 neg cx call @@draw_column add di, 20 inc si cmp si, 4 jb @@5 pop es ret @@translate_period: ; aka. wavelen, or divider ; Make symbol for the period (0..3FFh). ; hz = 3579545/16/2/tandydivider ; hz = 2^((linearnote-34)/12)*440 ; SOLVE linearnote ; v=1000 - 3 * (linearnote) ; v=610.3605-36*log2(1/tandydivider) fld f_notemul mov [f_temp].word0, ax fild dword ptr [f_temp] fld1 fdivrp st(1), st fyl2x fadd f_noteadd fistp [f_temp] fwait mov ax, [f_temp].word0 xor dx, dx mov bx, NumVisuals div bx ; Scale to NumVisuals range mov bx, dx shl bx, 1 mov ax, Visuals[bx] ; color & char ret @@draw_column: ; Draw column. ; IN: ax = color and character ; cx = number of blank lines ; bp = number of spaces before rep_blanks MACRO xchg ax,si rep stosw xchg ax,si ENDM push si push di mov si,0720h mov dx,cx @@1: cmp di,17*40*2-1 ja @@6 or dx, dx jz @@2 ; Draw blank column mov cx,10 rep_blanks dec dx jmp @@3 @@2: ; Draw colored column mov cx,bp jcxz @@2b rep_blanks @@2b: mov cx,8 rep stosw mov cx,2 sub cx,bp jbe @@3 rep_blanks @@3: add di,30*2 jmp @@1 @@6: pop di pop si ret ;;;;;;;;;;;;; ;; UTILITY ;; ;;;;;;;;;;;;; GetParamStr: ;; IN: DX = Parameter string number ;; OUT: AX = Length, ES:SI = String pointer les di, dword ptr cmdline mov cl, es:[di] xor ch, ch inc di ; Loop while we've got space ahead @@get_next_param: jcxz @@got_param_begin @@skip_space: cmp byte ptr es:[di], ' ' ja @@got_param_begin inc di loop @@skip_space @@got_param_begin: mov si, di ; Save beginning of param jcxz @@got_param_end @@wait_space: cmp byte ptr es:[di], ' ' jbe @@got_param_end inc di loop @@wait_space @@got_param_end: mov ax,di sub ax,si je @@done ; End if param is empty dec dx jnz @@get_next_param @@done: ret ;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; HARDWARE I/O ROUTINES ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;; SetupPIT: ; AX = PIT clock period ; (Divider to 1193180 Hz) push ax mov al, 34h out 43h, al pop ax out 40h, al mov al, ah out 40h, al ret SetupAudio: ; CH = CHANNEL (0..3) ; AL = VOLUME (0..15) ; DX = PERIOD (inverse of frequency) ; USES: AX,BX,CX,DX,SI ; Fixed volume for channel 2 cmp ch, 2 jne @@2 test al, al jz @@2 mov al, 6 @@2: ; Save data for visualization mov bl, ch mov bh, 0 mov si, bx mov ch_volume[si], al test al, al jz @@1 add si, si mov bx, ch_period[si] sub bx, dx mov ch_delta[si], bx mov ch_period[si], dx @@1: if 0 ; The SN76489 chip has a ridiculous ; high lower limit on its allowed ; pitches. For channel 3 (bass), ; we use the standard PC speaker ; instead. This works because bass ; has a constant volume. This also ; leaves the Tandy channel 3 free ; for defining the noise pitch. ; ; Note that this is a tradeoff: ; If you use this, both the noises ; and the bass channel will have ; more range, but the bass will also ; be much louder than it should. ; If you prefer the bass be at ; a moderate volume, disable this ; code. It is disabled by default. cmp ch, 2 je SetupPCspeaker ; Use PC speaker cmp ch, 3 jne SetupSN76489 ; Noise: Set pitch on channel 3 push ax mov ax, dx ; multiply by 3 add ax, ax add dx, ax shr dx, 4 ; divide by 16 mov ch, 2 ; wl = inwl*3/16 mov al, 0 call SetupSN76489 pop ax ; Noise 7: Copy pitch from channel 3. mov ch, 3 mov dx, 7 endif ;jmp SetupSN76489 SetupSN76489: ; IN: CH=CHANNEL,AL=VOLUME,DX=PERIOD cmp ch, 3 jne @@checkpitchrange ; Noise 4 ~ period 84.7 (0-127) ; Noise 5 ~ period 169.5 (128-255) ; Noise 6 ~ period 339.0 (256-1023) mov cl, 7 ; divide by 128 shr dx, cl add dl, 4 cmp dx, 6 jbe @@checkpitchrange mov dx, 6 @@checkpitchrange: ; If the pitch is too low, increase by an octave ; The SN76489 chip has a ridiculous high ; lower limit on its allowed pitches (109 Hz). cmp dx, 3FFh jbe @@4 shr dx, 1 jmp @@checkpitchrange @@4: mov bx, OFFSET TandyVolumeTable xlatb ; Translate volume or al, 90h ; Set bits for volume call @@out mov ax, dx ; Set period 4 low bits and al, 0Fh or al, 80h ; Set bits for period.lo call @@out mov ax, dx ; Set period 6 high bits mov cx, 4 ; ch:=0, cl:=4 shr ax, cl and al, 3Fh @@out: mov ah, ch ; Add channel aad 20h ; al := al + ah * 20h out 0C0h, al ret if 0 SetupPCspeaker: ; Reprogram the standard PC speaker ; IN: AL=VOLUME, DX=PERIOD test al, al jz @@pcquiet mov al, 0B6h out 43h, al ; 3579545/16/2/tandydivider = 1193180/pcdivider ; Solve pcdivider --> we get ~32/3. xchg ax, dx mov bx, 32 mul bx mov bx, 3 div bx out 42h, al mov al, ah out 42h, al in al, 61h ; Enable sound or al, 3 jmp @@s @@pcquiet: in al, 61h ; Disable sound and al, 0FCh @@s:out 61h, al ret endif ;;;;;;;;;;; ;;; IRQ ;;; ;;;;;;;;;;; ASSUME CS:text,DS:nothing,ES:nothing NewI08:; New INT 08 (timer IRQ) handler push ax mov [IRQticked], 1 add [I08counter], PITdivider jnc SkipOldI08 pop ax db 0EAh ; Jump far OldI08 dd 0 ; Old INT 08 vector SkipOldI08: mov al, 20h ; Send the EOI signal out 20h, al ; to the IRQ controller pop ax iret ; Exit interrupt IRQticked db 0 I08counter dw ? ; I08counter makes it possible to call the ; the old IRQ vector at the right rate. ; At every INT, it is incremented by: ; 10000h * (oldrate/newrate) ; Which happens to evaluate into the same ; as PITdivider when the oldrate is the ; standard ~18.2 Hz. Whenever it overflows, ; it's time to call the old IRQ handler. ; This ensures that the old IRQ handler is ; called at the standard 18.2 Hz rate. text ENDS ;;;;;;;;;;;; ;;;;;;;;;;;; data SEGMENT PARA PUBLIC ; Messages UnprintableErr db 'Unprintable error$' DOSerror2 db 'File not found$' DOSerror3 db 'Path not found$' DOSerror4 db 'Too many open files$' DOSerror5 db 'Access denied$' ErrorPart0 db '$' ErrorPart1 db ': $' ErrorPart2 db 13,10,'$' Error_Fmt db 'Not a valid SND file$' EndOfFile db 'End of file reached.$' PlayingMsg0 db 'Playing $' PlayingMsg1 db '. Hit a key to end.' db 10,10,10,10,10,10,10,10,10 db 10,10,10,10,10,10,10,10,10 db 'Player created by Joel Yliluoma' db 13,10, 'in July 2011, for Tandy 1000 and' db 13,10, 'assembler programming illustration.' db 13,10,10,'Thanks for watching!' db 13,10, ' ' db '[Click to subscribe!]$' UsageMsg db 'Usage: TANDYSND file.snd' db 13,10,'$' TandyVolumeTable equ $ ; Translate linear volume into ; Tandy's 2dB increments volume ; 0 1 2 3 4 5 6 7 db 15,11, 8, 7, 5, 4, 4, 3 ; 8 9 10 11 12 13 14 15 db 2, 2, 1, 1, 1, 0, 0, 0 Visuals dw 51DBh,51B1h,51B0h, 45DBh,45B1h,45B0h dw 64DBh,64B1h,64B0h, 26DBh,26B1h,26B0h dw 32DBh,32B1h,32B0h, 63DBh,63B1h,63B0h dw 56DBh,56B1h,56B0h, 25DBh,25B1h,25B0h dw 42DBh,42B1h,42B0h, 14DBh,14B1h,14B0h dw 71DBh,71B1h,71B0h, 17DBh,17B1h,17B0h ;Color symbols for visualization NumVisuals equ ($-Visuals)/2 FileNamePtr dd 0 ; Location of fname FileNameLength dw 0 ; Its length songfd dw 0 ; Handle of the SND file songsp dw 0 ; SP for song error returns bufsize dw 0 ; Amount of data in buffer bufreadpos dw 0 ; Buffer reading position pending db 0 ; Playing delay control cmdline dw 80h ; PSP offset to cmdline psp dw 0 ; Program Segment Prefix f_notemul dq -36.0 f_noteadd dq 610.36054 f_temp dq 0 ; FPU math temporary ch_period dw 0,0,0,0 ; Visualization ch_delta dw 0,0,0,0 ch_volume db 0,0,0,0 VisMem dw 40*2, 0B800h data ENDS ;;;;;;;;;;;; ;;;;;;;;;;;; buffers SEGMENT PARA PUBLIC filebuf_size equ 128 filebuffer db filebuf_size dup (?) songhdr db 16 dup (?) signature equ (byte ptr songhdr+0) fileversion equ (byte ptr songhdr+4) channelcount equ (byte ptr songhdr+5) rate equ (byte ptr songhdr+6) buffers ENDS ;;;;;;;;;;;; ;;;;;;;;;;;; END main