************************************************************************ * C. A. M. D. * ************************************************************************ * CMU Amiga Midi Driver - Carnegie Mellon University * * 1988 - Commodore Amiga * * * * Design & Development - Roger B. Dannenberg * * - Jean-Christophe Dhellemmes * * - Bill Barton * * Copyright 1989 Carnegie Mellon University * ************************************************************************ * * internal.asm - Example CAMD MIDI Device Driver for internal serial * port. * * This is merely an example. The internal serial port is normally * managed by camd.library. * ************************************************************************ * Date | Change *----------------------------------------------------------------------- * 06-Jan-1990 : Created (BB) ************************************************************************ nolist include "exec/types.i" include "exec/execbase.i" ; for FlushDevice() include "exec/macros.i" include "hardware/cia.i" include "hardware/custom.i" include "hardware/intbits.i" include "midi/devices.i" include "resources/misc.i" list Version equ 0 Revision equ 0 Ports equ 1 section driver,data ; external xref _AbsExecBase xref _custom xref _ciab section driver,code **************************************************************** * * Standard MIDI Device driver header * **************************************************************** ; code at start of file in case anyone tries to execute us as a program entry FalseStart FalseStart moveq #-1,d0 rts MDD ; struct MidiDeviceData dc.l MDD_Magic ; mdd_Magic dc.l Name ; mdd_Name dc.l IDString ; mdd_IDString dc.w Version ; mdd_Version dc.w Revision ; mdd_Revision dc.l Init ; mdd_Init dc.l Expunge ; mdd_Expunge dc.l OpenPort ; mdd_OpenPort dc.l ClosePort ; mdd_ClosePort dc.b Ports ; mdd_NPorts dc.b 0 ; mdd_Flags Name dc.b 'Internal',0 IDString dc.b 'Internal serial port MIDI device driver',0 ds.w 0 ; force word alignment **************************************************************** * * Serial Port Stuff * **************************************************************** SerFreq_NTSC equ 3579545 SerFreq_PAL equ 3546895 MIDIBPS equ 31250 SetSerPer macro ; freq move.w #(\1+MIDIBPS/2)/MIDIBPS-1,SerPer ; bits 0-14: period. bit 15: 9/8 bit selection endm INTF_CLR equ 0 BITDEF INT,SET,INTB_SETCLR ; serdatr register bit def's (not found in any include file) BITDEF SERDAT,OVRUN,15 BITDEF SERDAT,RBF,14 BITDEF SERDAT,TBE,13 BITDEF SERDAT,TSRE,12 STRUCTURE SerInt,IS_SIZE UWORD si_pad0 APTR si_OldInt APTR si_Data APTR si_Code LABEL SerInt_Size section driver,data ; data MiscBase ds.l 1 ; misc.resource pointer SerPer ds.w 1 ; serper value OldIntEna ds.w 1 ; original value of TBE and RBF bits MPD0 ; struct MidiPortData dc.l ActivateXmit SerXmitInt dc.l 0 ; ln_Succ dc.l 0 ; ln_Pred dc.b NT_INTERRUPT ; ln_Type dc.b 0 ; ln_Pri dc.l Name ; ln_Name dc.l SerXmitInt+si_Data ; is_Data dc.l XmitHandler ; is_Code dc.w 0 ; si_pad0 dc.l 0 ; si_OldInt dc.l 0 ; si_Data dc.l 0 ; si_Code SerRecvInt dc.l 0 ; ln_Succ dc.l 0 ; ln_Pred dc.b NT_INTERRUPT ; ln_Type dc.b 0 ; ln_Pri dc.l Name ; ln_Name dc.l SerRecvInt+si_Data ; is_Data dc.l RecvHandler ; is_Code dc.w 0 ; si_pad0 dc.l 0 ; si_OldInt dc.l 0 ; si_Data dc.l 0 ; si_Code section driver,code **************************************************************** * * MidiDeviceData Functions * **************************************************************** **************************************************************** * * Init * * FUNCTION * Gets called by CAMD after being LoadSeg'ed. * * INPUTS * None * * RESULTS * TRUE if successful, FALSE on failure. * **************************************************************** init_reg reg a6 Init movem.l init_reg,-(sp) move.l _AbsExecBase,a6 ; A6 = SysBase ; get misc.resource pointer lea MiscName,a1 ; open misc.resource JSRLIB OpenResource move.l d0,MiscBase beq init_ret ; calculate SerPer cmp.b #50,VBlankFrequency(a6) ; is PAL? beq init_pal SetSerPer SerFreq_NTSC ; set our local SerPer variable (not custom.serper) bra init_serperdone init_pal SetSerPer SerFreq_PAL ; set out local SerPer variable init_serperdone moveq #1,d0 ; return TRUE init_ret movem.l (sp)+,init_reg rts **************************************************************** * * Expunge * * FUNCTION * Gets called by CAMD immediately before being * UnLoadSeg'ed. * * INPUTS * None * * RESULTS * None * **************************************************************** Expunge rts **************************************************************** * * OpenPort * * FUNCTION * Open a MIDI port. * * INPUTS * D0.b - Port number (should always be 0 for this driver) * A0 - Xmit function * A1 - Recv function * A2 - Data * * RESULT * D0 - pointer to MidiPortData structure. * **************************************************************** op_reg reg a6 OpenPort movem.l op_reg,-(sp) move.l _AbsExecBase,a6 ; A6 = SysBase movem.l a0/a1,-(sp) ; save a0/a1 bsr AllocSerial movem.l (sp)+,a0/a1 ext.l d0 beq op_ret ; set SerXmitInt move.l a0,SerXmitInt+si_Code move.l a2,SerXmitInt+si_Data ; set SerRecvInt move.l a1,SerRecvInt+si_Code move.l a2,SerRecvInt+si_Data lea _custom,a0 ; A0 = custom move.w #INTF_TBE!INTF_RBF,d1 ; D1 = RBF | TBE mask and int disable ; save original TBE and RBF intena settings move.w intenar(a0),d0 and.w d1,d0 ; mask with RBF|TBE mask move.w d0,OldIntEna move.w d1,intena(a0) ; disable TBE and RBF interrupts move.w d1,intreq(a0) ; clear pending TBE and RBF interrupts move.w SerPer,serper(a0) ; set serper ; set TBE interrupt vector moveq #INTB_TBE,d0 lea SerXmitInt,a1 JSRLIB SetIntVector move.l d0,SerXmitInt+si_OldInt ; save old vector ; set RBF interrupt vector moveq #INTB_RBF,d0 lea SerRecvInt,a1 JSRLIB SetIntVector move.l d0,SerRecvInt+si_OldInt ; save old vector move.w #INTF_SET!INTF_RBF,_custom+intena ; enable RBF move.w #INTF_SET!INTF_TBE,_custom+intreq ; set a pending TBE bclr.b #CIAB_COMDTR,_ciab+ciapra ; turn on DTR bit (active low) lea MPD0,a0 move.l a0,d0 ; return pointer to MidiPortData op_ret movem.l (sp)+,op_reg rts **************************************************************** * * ClosePort * * FUNCTION * Close a MIDI port. * * INPUTS * D0.b - Port number (always 0 for this driver). * * RESULT * None * **************************************************************** cp_reg reg a6 ClosePort movem.l cp_reg,-(sp) move.l _AbsExecBase,a6 ; A6 = SysBase bsr WaitSerial bset.b #CIAB_COMDTR,_ciab+ciapra ; turn off DTR bit (active low) move.w #INTF_CLR!INTF_TBE!INTF_RBF,_custom+intena ; disable RBF & TBE move.w #INTF_CLR!INTF_TBE!INTF_RBF,_custom+intreq ; clear pending RBF & TBE requests ; restore original TBE interrupt vector moveq #INTB_TBE,d0 move.l SerXmitInt+si_OldInt,a1 JSRLIB SetIntVector ; restore original RBF interrupt vector moveq #INTB_RBF,d0 move.l SerRecvInt+si_OldInt,a1 JSRLIB SetIntVector move.w OldIntEna,d0 beq cp_nointena or.w #INTF_SET,d0 move.w d0,_custom+intena cp_nointena bsr FreeSerial movem.l (sp)+,cp_reg rts **************************************************************** * * ActivateXmit * * FUNCTION * Activate the transmit interrupt. There is normally * one of these functions for every port in order to * reduce table lookup time. * * INPUTS * A2 - Data passed to OpenPort() (not used here) * * RESULT * None * **************************************************************** ActivateXmit move.w #INTF_SET!INTF_TBE,_custom+intena ; enable TBE interrupt, but leave request pending rts **************************************************************** * * WaitSerial * * FUNCTION * Wait until Amiga serial port TSRE bit is set. This * indicates that the serial shift register is empty. * * INPUTS * None * * RESULTS * None * * NOTE * This function busy waits!!! It should only be called * once the transmit queue has emptied (i.e. TBE has * already been set) such that no more than 320us is * wasted here. * **************************************************************** ws_reg reg WaitSerial movem.l ws_reg,-(sp) ws_loop move.w _custom+serdatr,d0 btst.l #SERDATB_TSRE,d0 beq ws_loop movem.l (sp)+,ws_reg rts **************************************************************** * * Serial Interrupt Handlers * **************************************************************** **************************************************************** * * XmitHandler * * FUNCTION * Amiga serial port transmit interrupt handler. Calls * the general transmit handler and expects a byte in * D0 and a last byte flag in D1. * * When the last byte is detected, the TBE interrupt * is disabled, thus deferring calling XmitHandler * again until there are some bytes ready to send. * CAMD calls ActivateXmit when there are more bytes * to send. * * INPUTS * A0 - custom * A1 - Data * A6 - SysBase * * RESULTS * None * * NOTE * A5 is scratch. * **************************************************************** sxh_reg reg a2 XmitHandler movem.l sxh_reg,-(sp) movem.l (a1),a2/a5 ; A2 = Data, A5 = XmitHandler sxh_loop move.w #INTF_CLR!INTF_TBE,_custom+intreq ; clear TBE interrupt request jsr (a5) ; returns byte in D0, last byte flag in D1 or.w #$100,d0 ; add stop bit move.w d0,_custom+serdat ; send byte tst.b d1 ; is last byte? beq sxh_notlast ; xmit queue is empty move.w #INTF_CLR!INTF_TBE,_custom+intena ; disable TBE interrupt. bra sxh_done ; next request remains pending until there are more bytes to send sxh_notlast ; test for another TBE btst.b #INTB_TBE&7,_custom+intreqr+(15-INTB_TBE)/8 bne sxh_loop sxh_done movem.l (sp)+,sxh_reg rts if 0 **************************************************************** * * XmitHandler * * FUNCTION * Amiga serial port transmit interrupt handler. Called * by TBE interrupt vector. Calls the CAMD transmit * handler and expects one of the following return values * in d0.w: * * $00mm - a MIDI byte in the lower byte to transmit. * $ffff - if no byte to send (queue was empty). * * INPUTS * A0 - custom * A1 - pointer to SerInt.Data * A6 - SysBase * * RESULTS * None * * NOTE * A5 is scratch. * **************************************************************** sxh_reg reg a2 XmitHandler movem.l sxh_reg,-(sp) movem.l (a1),a2/a5 sxh_loop move.w #INTF_TBE,intreq(a0) ; clear the interrupt request jsr (a5) or.w #$100,d0 ; add stop bit bmi sxh_skip ; if negative, there's no byte to send lea _custom,a0 ; see if TBE is still set move.w d0,serdat(a0) ; send byte move.w intreqr(a0),d0 ; (don't know if btst.b is safe on custom chips) and.w #INTF_TBE,d0 ; ^^^ JOE: It's not!! bne sxh_loop sxh_skip movem.l (sp)+,sxh_reg rts endc **************************************************************** * * RecvHandler * * FUNCTION * Amiga serial port receive interrupt handler. Called * by RBF interrupt vector. Calls the CAMD receive * handler with received data until there are no more bytes * pending in the serial receive hardware. * * INPUTS * A0 - custom * A1 - pointer to SerInt.Data * A6 - SysBase * * RESULTS * None * * NOTE * A5 is scratch. * **************************************************************** srh_reg reg a2 RecvHandler movem.l srh_reg,-(sp) movem.l (a1),a2/a5 move.w serdatr(a0),d0 srh_loop move.w #INTF_CLR!INTF_RBF,intreq(a0) ; clear the interrupt request jsr (a5) lea _custom,a0 ; see if RBF is still set move.w serdatr(a0),d0 btst.l #SERDATB_RBF,d0 bne srh_loop movem.l (sp)+,srh_reg rts **************************************************************** * * misc.resource serial stuff * **************************************************************** **************************************************************** * * AllocSerial * * FUNCTION * Allocate misc.resource channels for the serial port. * Call FlushDevice("serial.device") on failure and try * again. * * INPUTS * A6 - SysBase * * RESULT * D0.w - TRUE on success. * **************************************************************** as_reg reg AllocSerial movem.l as_reg,-(sp) JSRLIB Forbid ; remain atomic bsr AttemptSerMisc ; attempt to get serial misc.resource channels tst.w d0 bne as_done ; if OK, return lea SerialName,a1 ; otherwise, FlushDevice("serial.device") bsr FlushDevice bsr AttemptSerMisc ; and try the serial misc.resource stuff again as_done move.w d0,-(sp) JSRLIB Permit move.w (sp)+,d0 movem.l (sp)+,as_reg rts **************************************************************** * * AttemptSerMisc * * FUNCTION * Attempt to allocate misc.resource channels for the * serial port. * * INPUTS * None * * RESULT * D0.w - TRUE on success. * **************************************************************** asm_reg reg a6 AttemptSerMisc movem.l asm_reg,-(sp) move.l MiscBase,a6 ; A6 = MiscBase moveq #MR_SERIALBITS,d0 ; alloc SERIALBITS lea Name,a1 JSRLIB AllocMiscResource tst.l d0 ; if return is non-zero, it's in use bne asm_fail moveq #MR_SERIALPORT,d0 ; alloc SERIALPORT lea Name,a1 JSRLIB AllocMiscResource tst.l d0 ; if return is zero, we got it beq asm_ok moveq #MR_SERIALBITS,d0 ; free SERIALBITS on SERIALPORT failure JSRLIB FreeMiscResource asm_fail moveq #0,d0 bra asm_ret asm_ok moveq #1,d0 asm_ret movem.l (sp)+,asm_reg rts **************************************************************** * * FreeSerial * * FUNCTION * Free misc.resource channels for the serial port. * * INPUTS * None * * RESULT * None * **************************************************************** fs_reg reg a6 FreeSerial movem.l fs_reg,-(sp) move.l MiscBase,a6 ; A6 = MiscBase moveq #MR_SERIALBITS,d0 ; free SERIALBITS JSRLIB FreeMiscResource moveq #MR_SERIALPORT,d0 ; free SERIALPORT JSRLIB FreeMiscResource movem.l (sp)+,fs_reg rts **************************************************************** * * FlushDevice * * FUNCTION * Force expunge of a Device. * * INPUTS * A1 - Name of device. * A6 - SysBase * * RESULT * None * * NOTE * Assumes caller has surrounded this call with * Forbid/Permit * **************************************************************** fd_reg reg FlushDevice movem.l fd_reg,-(sp) lea DeviceList(a6),a0 JSRLIB FindName tst.l d0 ; if not in the device list, skip beq fd_ret move.l d0,a1 ; otherwise force expunge JSRLIB RemDevice fd_ret movem.l (sp)+,fd_reg rts MiscName MISCNAME SerialName dc.b 'serial.device',0 end