rework in CBDOS

src/dos_m65/,aliases_dos.s

@@ -13,20 +13,34 @@
 
 	!addr MAGICSTR         = $8000 ; magic string; if not matching, DOS considered non-functional
 
+	; Register storage
+
+	!addr REG_A            = $8005
+	!addr REG_X            = $8006
+	!addr REG_Y            = $8007
+	!addr REG_Z            = $8008
+
+	; Reserved: $8009 - $800C
+
 	; General DOS configuration
 
-	!addr UNIT_SDCARD      = $8005 ; unit number for device, 0 = none
+	!addr UNIT_SDCARD      = $800D ; unit number for device, 0 = none
-	!addr UNIT_FLOPPY      = $8006 ; as above
+	!addr UNIT_FLOPPY      = $800E ; as above
-	!addr UNIT_RAMDISK     = $8007 ; as above
+	!addr UNIT_RAMDISK     = $800F ; as above
 
 	; General DOS status
 
-	!addr IDX1_LISTENER    = $8008 ; listener idx, >=$80 = none
+	!addr IDX1_LISTENER    = $8010 ; listener idx, >=$80 = none
-	!addr IDX2_LISTENER    = $8009 ; listener idx * 2, >=$80 = none - for calling routines via vector table
+	!addr IDX2_LISTENER    = $8011 ; listener idx * 2, >=$80 = none - for calling routines via vector table
-	!addr IDX1_TALKER      = $800A ; talker idx, >=$80 = none
+	!addr IDX1_TALKER      = $8012 ; talker idx, >=$80 = none
-	!addr IDX2_TALKER      = $800B ; talker idx * 2, >=$80 = none - for calling routines via vector table
+	!addr IDX2_TALKER      = $8013 ; talker idx * 2, >=$80 = none - for calling routines via vector table
 
-	; Free space: $800C-$8069
+	; Free space: $8014-$8063
+
+	!addr XX_MODE          = $8064 ; current mode (0 = none, 1 = receiving command/file name)
+	!addr SD_MODE          = $8064 ; - SD card
+	!addr FD_MODE          = $8065 ; - floppy
+	!addr RD_MODE          = $8066 ; - ram disk
 
 	!addr XX_CHANNEL       = $8067 ; current channel
 	!addr SD_CHANNEL       = $8067 ; - SD card

src/dos_m65/4020.dos_vectable.s

@@ -5,11 +5,11 @@
 !word dos_UNITCHK
 !word dos_UNITSET
 !word dos_UNITNUM
-!word dos_ACPTR
+!word msg_ACPTR
-!word dos_CIOUT
+!word msg_CIOUT
-!word dos_LISTEN
+!word msg_LISTEN
-!word dos_SECOND
+!word msg_SECOND
-!word dos_TALK
+!word msg_TALK
-!word dos_TKSA
+!word msg_TKSA
-!word dos_UNTLK
+!word msg_UNTLK
-!word dos_UNLSN
+!word msg_UNLSN

src/dos_m65/dev_floppy/dev_fd_cmd_close.s

@@ -8,5 +8,4 @@ dev_fd_cmd_CLOSE:
 
 	; XXX provide implementation
 
-	sec
+	jmp dos_EXIT_SEC
-	jmp dos_SECOND_done

src/dos_m65/dev_floppy/dev_fd_cmd_open.s

@@ -8,5 +8,4 @@ dev_fd_cmd_OPEN:
 
 	; XXX provide implementation
 
-	sec
+	jmp dos_EXIT_SEC
-	jmp dos_SECOND_done

src/dos_m65/dev_floppy/dev_fd_init.s

@@ -11,6 +11,7 @@ dev_fd_init:
 	ldx #$00
 	stx FD_STATUS_IDX
 	stx FD_CMDFN_IDX
+	stx FD_MODE
 	dex
 @1:
 	inx

src/dos_m65/dev_ramdisk/dev_rd_cmd_close.s

@@ -8,5 +8,4 @@ dev_rd_cmd_CLOSE:
 
 	; XXX provide implementation
 
-	sec
+	jmp dos_EXIT_SEC
-	jmp dos_SECOND_done

src/dos_m65/dev_ramdisk/dev_rd_cmd_open.s

@@ -8,5 +8,4 @@ dev_rd_cmd_OPEN:
 
 	; XXX provide implementation
 
-	sec
+	jmp dos_EXIT_SEC
-	jmp dos_SECOND_done

src/dos_m65/dev_ramdisk/dev_rd_init.s

@@ -11,6 +11,7 @@ dev_rd_init:
 	ldx #$00
 	stx RD_STATUS_IDX
 	stx RD_CMDFN_IDX
+	stx RD_MODE
 	dex
 @1:
 	inx

src/dos_m65/dev_sdcard/dev_sd_cmd_close.s

@@ -8,5 +8,4 @@ dev_sd_cmd_CLOSE:
 
 	; XXX provide implementation
 
-	sec
+	jmp dos_EXIT
-	jmp dos_SECOND_done

src/dos_m65/dev_sdcard/dev_sd_cmd_open.s

@@ -6,7 +6,7 @@
 
 dev_sd_cmd_OPEN:
 
-	; XXX provide implementation
+	lda #$01                 ; mode: receive command or file name
+	sta SD_MODE
 
-	sec
+	jmp dos_EXIT
-	jmp dos_SECOND_done

src/dos_m65/dev_sdcard/dev_sd_init.s

@@ -11,6 +11,7 @@ dev_sd_init:
 	ldx #$00
 	stx SD_STATUS_IDX
 	stx SD_CMDFN_IDX
+	stx SD_MODE
 	dex
 @1:
 	inx

src/dos_m65/dos_acptr.s

@@ -1,80 +0,0 @@
-
-;
-; Implementation of ACPTR command. For detailed description see 'm65dos_bridge.s' file.
-;
-
-
-dos_ACPTR: ; does not have to preserve .X
-
-	ldx IDX1_TALKER
-	bmi dos_ACPTR_fail
-
-	lda XX_CHANNEL, X
-	cmp #$0F
-	beq dos_ACPTR_status
-
-	; XXX providde implementation for non-status streams
-
-	jmp dos_ACPTR_fail
-
-dos_ACPTR_status:
-
-	ldx IDX2_TALKER
-	jsr (dos_ACPTR_getsts_table, X)
-	sta TBTCNT                         ; byte return
-	beq dos_ACPTR_reset_status
-
-	clc
-	rts
-
-dos_ACPTR_fail:
-
-	; XXX set error code
-
-	sec
-	rts
-
-dos_ACPTR_reset_status:
-
-	lda IDX1_TALKER
-	jsr dos_status_00
-
-	; FALLTROUGH
-
-dos_ACPTR_eoi:
-
-	jsr kernalstatus_EOI
-	
-	clc
-	rts
-
-
-
-; Sending bytes from the status string
-
-dos_ACPTR_getsts_SD:                   ; get next byte of status - SD card
-
-	ldx SD_STATUS_IDX
-	inc SD_STATUS_IDX
-	lda SD_STATUS_STR,x
-	rts
-
-dos_ACPTR_getsts_FD:                   ; get next byte of status - floppy
-
-	ldx FD_STATUS_IDX
-	inc FD_STATUS_IDX
-	lda FD_STATUS_STR,x
-	rts
-
-dos_ACPTR_getsts_RD:                   ; get next byte of status - ram disk
-
-	ldx RD_STATUS_IDX
-	inc RD_STATUS_IDX
-	lda RD_STATUS_STR,x
-	rts
-
-dos_ACPTR_getsts_table:
-
-	!word dos_ACPTR_getsts_SD
-	!word dos_ACPTR_getsts_FD
-	!word dos_ACPTR_getsts_RD

src/dos_m65/dos_ciout.s

@@ -1,71 +0,0 @@
-
-;
-; Implementation of ACPTR command. For detailed description see 'm65dos_bridge.s' file.
-;
-
-
-dos_CIOUT:
-
-	pha
-	phx
-
-	; XXX handle cases of transferring data
-
-	; Receive command/file name byte
-
-	ldx IDX2_TALKER
-	jsr (dos_CIOUT_putcmdfn_table, X)
-
-	plx
-	pla
-
-	clc
-	rts
-
-
-
-
-
-; Receiving command/file name
-
-dos_CIOUT_putcmdfn_SD:                   ; get next byte of status - SD card
-
-	ldx SD_CMDFN_IDX
-	sta SD_CMDFN_IDX,x
-	inx
-	bpl @1
-	ldx #$7F
-@1:
-	lda #$00
-	sta SD_CMDFN_IDX,x
-	rts
-
-dos_CIOUT_putcmdfn_FD:                   ; get next byte of status - floppy
-
-	ldx FD_CMDFN_IDX
-	sta FD_CMDFN_IDX,x
-	inx
-	bpl @1
-	ldx #$7F
-@1:
-	lda #$00
-	sta FD_CMDFN_IDX,x
-	rts
-
-dos_CIOUT_putcmdfn_RD:                   ; get next byte of status - ram disk
-
-	ldx RD_CMDFN_IDX
-	sta RD_CMDFN_IDX,x
-	inx
-	bpl @1
-	ldx #$7F
-@1:
-	lda #$00
-	sta RD_CMDFN_IDX,x
-	rts
-
-dos_CIOUT_putcmdfn_table:
-
-	!word dos_CIOUT_putcmdfn_SD
-	!word dos_CIOUT_putcmdfn_FD
-	!word dos_CIOUT_putcmdfn_RD

src/dos_m65/dos_enter_exit.s

@@ -0,0 +1,54 @@
+
+; Helper routines for entering/exiting the context
+
+
+
+dos_ENTER:         ; enter DOS context
+ 
+	sta REG_A
+	stx REG_X
+	sty REG_Y
+	stz REG_Z
+
+	rts
+
+
+dos_EXIT_SEC:      ; exit DOS context with Carry set
+
+	sec
+	bra dos_EXIT_common
+
+dos_EXIT:          ; exit DOS context with Carry clear
+
+	clc
+
+	; FALLTROUGH
+
+dos_EXIT_common:
+
+	ldz REG_Z
+	ldy REG_Y
+	ldx REG_X
+	lda REG_A
+
+	rts
+
+
+dos_EXIT_A_SEC:    ; exit DOS context with Carry set, return .A
+
+	sec
+	bra dos_EXIT_A_common
+
+dos_EXIT_A:        ; exit DOS context with Carry clear, return .A
+
+	clc
+
+	; FALLTROUGH
+
+dos_EXIT_A_common:
+
+	ldz REG_Z
+	ldy REG_Y
+	ldx REG_X
+
+	rts

src/dos_m65/dos_error.s

@@ -12,10 +12,6 @@
 
 dos_status_00: ; OK
 
-	pha
-	phx
-	phy
-
 	; Set status byte pointer to the beginning
 
 	tax
@@ -76,11 +72,6 @@ dos_status_00: ; OK
 
 	; End
 
-	ply
-	plx
-	pla
-
-	clc ; mark status as OK 
 	rts
 
 

src/dos_m65/dos_init.s

@@ -10,9 +10,10 @@
 
 dos_INIT:
 
+	jsr dos_ENTER
+
 	; Set the magic string 'CBDOS'
 
-	phx
 	ldx #$04
 @1:
 	lda dos_magicstr, x
@@ -20,8 +21,6 @@ dos_INIT:
 	dex
 	bpl @1
 
-	plx
-
 	; Set default device numbers
 
 	lda #CONFIG_UNIT_SDCARD
@@ -45,4 +44,6 @@ dos_INIT:
 	jsr dev_fd_init
 	jsr dev_rd_init
 
-	rts
+	; Exit DOS context
+
+	jmp dos_EXIT

src/dos_m65/dos_listen_talk.s

@@ -1,110 +0,0 @@
-
-;
-; Implementation of LISTEN/UNLSN/TALK/UNTLK commands.
-; For detailed description see 'm65dos_bridge.s' file.
-;
-
-
-; LISTEN
-
-dos_LISTEN:
-
-	pha
-	and #$1F
-	beq dos_fail_TALK_LISTEN           ; branch if device 0 (used to denote lack of device)
-
-	cmp UNIT_SDCARD
-	bne @1
-
-	lda #$00
-	bra dos_LISTEN_success
-@1:
-	cmp UNIT_FLOPPY
-	bne @2
-
-	lda #$01
-	bra dos_LISTEN_success
-@2:
-	cmp UNIT_RAMDISK
-	bne dos_fail_TALK_LISTEN
-
-	lda #$02
-	
-	; FALLTROUGH
-
-dos_LISTEN_success:
-
-	sta IDX1_LISTENER
-	asl
-	sta IDX2_LISTENER
-
-	; XXX should we reset XX_CMDFN_IDX ?
-
-	bra dos_common_LSN_TALK_UN
-
-; TALK
-
-dos_TALK:
-
-	pha
-	and #$1F
-	beq dos_fail_TALK_LISTEN           ; branch if device 0 (used to denote lack of device)
-
-	cmp UNIT_SDCARD
-	bne @1
-
-	lda #$00
-	bra dos_TALK_success
-@1:
-	cmp UNIT_FLOPPY
-	bne @2
-
-	lda #$01
-	bra dos_TALK_success
-@2:
-	cmp UNIT_RAMDISK
-	bne dos_fail_TALK_LISTEN
-
-	lda #$02
-	
-	; FALLTROUGH
-
-dos_TALK_success:
-
-	sta IDX1_TALKER
-	asl
-	sta IDX2_TALKER
-
-	bra dos_common_LSN_TALK_UN
-
-dos_fail_TALK_LISTEN:
-
-	pla
-	lda #K_ERR_DEVICE_NOT_FOUND
-	sec
-	rts
-
-; UNLSN / UNTLK
-
-dos_UNLSN:
-
-	pha
-	lda #$FF
-	sta IDX1_LISTENER
-	sta IDX2_LISTENER
-	bra dos_common_LSN_TALK_UN
-
-dos_UNTLK:
-
-	pha
-	lda #$FF
-	sta IDX1_TALKER
-	sta IDX2_TALKER
-
-	; FALLTROUGH
-
-dos_common_LSN_TALK_UN:
-
-	pla
-	clc
-	rts

src/dos_m65/dos_memchk.s

@@ -8,9 +8,6 @@ dos_MEMCHK:
 
 	; Check for magic string
 
-	pha
-	phx
-
 	ldx #$04
 @1:
 	lda MAGICSTR, x
@@ -19,14 +16,10 @@ dos_MEMCHK:
 	dex
 	bpl @1
 
-	plx
-	pla
 	clc 
 	rts
 
 @fail:
 
-	plx
-	pla
 	sec
 	rts

src/dos_m65/dos_second_tksa.s

@@ -1,71 +0,0 @@
-
-;
-; Implementation of SECOND/TKSA commands.
-; For detailed description see 'm65dos_bridge.s' file.
-;
-
-
-dos_SECOND:
-
-	pha
-	phx
-	phy
-
-	; First store the channel
-
-	tay
-	and #$0F                   ; support channels 0-15, like 1541 drive
-
-	ldx IDX1_LISTENER
-	bmi dos_SECOND_done        ; do nothing if no listener
-	sta XX_CHANNEL, x          ; store channel
-
-	; Determine command type
-
-	tya	
-	and #$F0
-
-	cmp #$F0
-	beq dos_SECOND_OPEN
-	cmp #$E0
-	beq dos_SECOND_CLOSE
-
-	; XXX provide implementation
-
-	bra dos_SECOND_done
-
-dos_SECOND_OPEN:
-
-	ldx IDX2_LISTENER
-	jmp (dos_cmd_OPEN_vectable, x)
-
-dos_SECOND_CLOSE:
-
-	ldx IDX2_LISTENER
-	jmp (dos_cmd_CLOSE_vectable, x)
-
-dos_SECOND_done:
-
-	ply
-	bra dos_TKSA_done          ; reuse part of TKSA code
-
-
-dos_TKSA:
-
-	pha
-	phx
-
-	and #$0F                   ; support channels 0-15, like 1541 drive
-
-	ldx IDX1_TALKER
-	bmi dos_TKSA_done          ; do nothing if no taalker
-	sta XX_CHANNEL, x          ; store channel
-
-	; FALLTROUGH
-
-dos_TKSA_done:
-
-	plx
-	pla
-	clc
-	rts

src/dos_m65/dos_unitchk.s

@@ -6,10 +6,12 @@
 
 dos_UNITCHK:
 
+	jsr dos_ENTER
+
 	; Check if memory content is not damaged
 
 	jsr dos_MEMCHK
-	bcs dos_UNITCHK_none
+	bcs dos_UNITCHK_fail
 
 	; Check for unit
 
@@ -22,10 +24,9 @@ dos_UNITCHK:
 
 	; FALLTROUGH
 
-dos_UNITCHK_none:
+dos_UNITCHK_fail:
 
-	sec
+	jmp dos_EXIT_SEC
-	rts
 
 dos_UNITCHK_sdcard:
 
@@ -45,12 +46,4 @@ dos_UNITCHK_ramdisk:
 
 	lda #$02
 
-	clc
+	jmp dos_EXIT_A
-	rts
-
-dos_UNITCHK_mem_fail:
-
-	plx
-	pla
-	sec
-	rts

src/dos_m65/dos_unitnum.s

@@ -6,10 +6,13 @@
 
 dos_UNITNUM:
 
+	jsr dos_ENTER
+
 	; Check if memory content is not damaged
 
 	jsr dos_MEMCHK
-	bcs dos_UNITNUM_none
+	bcs dos_UNITNUM_fail
+	lda REG_A
 
 	; Check what kind of device was requested
 
@@ -22,12 +25,11 @@ dos_UNITNUM:
 
 	; FALLTROUGH
 
-dos_UNITNUM_none:
+dos_UNITNUM_fail:
 
 	lda #$00
 
-	sec
+	jmp dos_EXIT_A_SEC
-	rts
 
 dos_UNITNUM_sdcard:
 
@@ -42,13 +44,12 @@ dos_UNITNUM_floppy:
 dos_UNITNUM_ramdisk:
 
 	lda UNIT_RAMDISK
-	bra dos_UNITNUM_common
+	
+	; FALLTROUGH
 
 dos_UNITNUM_common:
 
 	cmp #$00
-	beq dos_UNITNUM_none
+	beq dos_UNITNUM_fail
-
-	clc
-	rts
 
+	jmp dos_EXIT_A

src/dos_m65/dos_unitset.s

@@ -6,6 +6,8 @@
 
 dos_UNITSET:
 
+	jsr dos_ENTER
+
 	; Check if memory content is not damaged
 
 	jsr dos_MEMCHK
@@ -18,14 +20,13 @@ dos_UNITSET:
 
 	cmp #$00
 	beq dos_UNITSET_sdcard
-	; XXX devioces below are not implemented yet
+	; XXX devices below are not implemented yet
 	; cmp #$01
 	; beq dos_UNITSET_floppy
 	; cmp #$02
 	; beq dos_UNITSET_ramdisk
 
-	sec
+	jmp dos_EXIT_SEC
-	rts
 
 dos_UNITSET_sdcard:
 
@@ -45,7 +46,4 @@ dos_UNITSET_ramdisk:
 
 	stx UNIT_RAMDISK
 
-	; FALLTROUGH
+	jmp dos_EXIT
-
-	clc
-	rts

src/dos_m65/dos_vectab_dev.s

@@ -4,14 +4,14 @@
 ;
 
 
-dos_cmd_OPEN_vectable:
+dos_cmd_OPEN_vectab:
 
 	!word dev_sd_cmd_OPEN
 	!word dev_fd_cmd_OPEN
 	!word dev_rd_cmd_OPEN
 
 
-dos_cmd_CLOSE_vectable:
+dos_cmd_CLOSE_vectab:
 
 	!word dev_sd_cmd_CLOSE
 	!word dev_fd_cmd_CLOSE

src/dos_m65/msg_acptr.s

@@ -0,0 +1,86 @@
+
+;
+; Implementation of ACPTR command. For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_ACPTR:
+
+	jsr dos_ENTER
+
+	; Check if there is a talker active
+
+	ldx IDX1_TALKER
+	bmi msg_ACPTR_fail
+
+	; Check if active channel is status one
+
+	lda XX_CHANNEL, X
+	cmp #$0F
+	beq msg_ACPTR_status
+
+	; XXX providde implementation for non-status channels
+
+	jmp msg_ACPTR_fail
+
+msg_ACPTR_status:
+
+	ldx IDX2_TALKER
+	jmp (msg_ACPTR_status_vectab, X)
+
+msg_ACPTR_status_SD:                   ; get next byte of status - SD card
+
+	ldx SD_STATUS_IDX
+	inc SD_STATUS_IDX
+	lda SD_STATUS_STR,x
+	bra msg_ACPTR_status_got
+
+msg_ACPTR_status_FD:                   ; get next byte of status - floppy
+
+	ldx FD_STATUS_IDX
+	inc FD_STATUS_IDX
+	lda FD_STATUS_STR,x
+	bra msg_ACPTR_status_got
+
+msg_ACPTR_status_RD:                   ; get next byte of status - ram disk
+
+	ldx RD_STATUS_IDX
+	inc RD_STATUS_IDX
+	lda RD_STATUS_STR,x
+
+	; FALLTROUGH
+
+msg_ACPTR_status_got:
+
+	sta TBTCNT                         ; byte return
+	beq msg_ACPTR_reset_status
+
+	jmp dos_EXIT
+
+msg_ACPTR_fail:
+
+	; XXX set error code
+
+	jmp dos_EXIT_SEC
+
+msg_ACPTR_reset_status:
+
+	lda IDX1_TALKER
+	jsr dos_status_00
+
+	; FALLTROUGH
+
+msg_ACPTR_eoi:
+
+	jsr kernalstatus_EOI
+	jmp dos_EXIT_SEC
+
+
+
+; Vector tables for jumps
+
+msg_ACPTR_status_vectab:
+
+	!word msg_ACPTR_status_SD
+	!word msg_ACPTR_status_FD
+	!word msg_ACPTR_status_RD

src/dos_m65/msg_ciout.s

@@ -0,0 +1,74 @@
+
+;
+; Implementation of ACPTR command. For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_CIOUT:
+
+	jsr dos_ENTER
+
+	; Check operation mode
+
+	ldx IDX1_LISTENER
+	lda XX_MODE, x
+
+	cmp #$01
+	bne @1
+
+	; Receiving command or file name
+
+	ldx IDX2_TALKER
+	jmp (msg_CIOUT_cmdfn_vectab, X)
+@1:
+	; XXX handle cases of transferring data
+
+	jmp dos_EXIT_SEC
+
+
+
+
+
+; Receiving command/file name
+
+msg_CIOUT_cmdfn_SD:                    ; get next byte of status - SD card
+
+	ldx SD_CMDFN_IDX
+	sta SD_CMDFN_IDX,x
+	inx
+	bpl @1
+	ldx #$7F
+@1:
+	lda #$00
+	sta SD_CMDFN_IDX,x
+	jmp dos_EXIT
+
+msg_CIOUT_cmdfn_FD:                    ; get next byte of status - floppy
+
+	ldx FD_CMDFN_IDX
+	sta FD_CMDFN_IDX,x
+	inx
+	bpl @1
+	ldx #$7F
+@1:
+	lda #$00
+	sta FD_CMDFN_IDX,x
+	jmp dos_EXIT
+
+msg_CIOUT_cmdfn_RD:                    ; get next byte of status - ram disk
+
+	ldx RD_CMDFN_IDX
+	sta RD_CMDFN_IDX,x
+	inx
+	bpl @1
+	ldx #$7F
+@1:
+	lda #$00
+	sta RD_CMDFN_IDX,x
+	jmp dos_EXIT
+
+msg_CIOUT_cmdfn_vectab:
+
+	!word msg_CIOUT_cmdfn_SD
+	!word msg_CIOUT_cmdfn_FD
+	!word msg_CIOUT_cmdfn_RD

src/dos_m65/msg_listen.s

@@ -0,0 +1,54 @@
+
+;
+; Implementation of LISTEN commands.
+; For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_LISTEN:
+
+	jsr dos_ENTER
+
+	and #$1F
+	beq msg_LISTEN_fail      ; branch if device 0 (used to denote lack of device)
+
+	cmp UNIT_SDCARD
+	bne @1
+
+	; LISTEN on SD card
+
+	lda #$00
+	bra msg_LISTEN_success
+@1:
+	cmp UNIT_FLOPPY
+	bne @2
+
+	; LISTEN on floppy
+
+	lda #$01
+	bra msg_LISTEN_success
+@2:
+	cmp UNIT_RAMDISK
+	bne msg_LISTEN_fail
+
+	; LISTEN on ram disk
+
+	lda #$02
+	
+	; FALLTROUGH
+
+msg_LISTEN_success:
+
+	sta IDX1_LISTENER
+	asl
+	sta IDX2_LISTENER
+
+	; XXX should we reset XX_CMDFN_IDX ?
+
+	jmp dos_EXIT
+
+msg_LISTEN_fail:
+
+	lda #K_ERR_DEVICE_NOT_FOUND
+
+	jmp dos_EXIT_A_SEC

src/dos_m65/msg_second.s

@@ -0,0 +1,49 @@
+
+;
+; Implementation of SECOND command.
+; For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_SECOND:
+
+	jsr dos_ENTER
+
+	; First store the channel
+
+	tay
+	and #$0F                   ; support channels 0-15, like 1541 drive
+
+	ldx IDX1_LISTENER
+	bmi msg_SECOND_done        ; do nothing if no listener
+	sta XX_CHANNEL, x          ; store channel
+
+	; Determine command type
+
+	tya	
+	and #$F0
+
+	cmp #$F0
+	beq msg_SECOND_OPEN
+	cmp #$E0
+	beq msg_SECOND_CLOSE
+
+	; XXX provide implementation
+
+	; FALLTROUGH
+
+msg_SECOND_done:
+
+	jmp dos_EXIT
+
+msg_SECOND_OPEN:
+
+	lda #$00
+	sta XX_CMDFN_IDX, x        ; reset the index to the command/filename
+	ldx IDX2_LISTENER
+	jmp (dos_cmd_OPEN_vectab, x)
+
+msg_SECOND_CLOSE:
+
+	ldx IDX2_LISTENER
+	jmp (dos_cmd_CLOSE_vectab, x)

src/dos_m65/msg_talk.s

@@ -0,0 +1,52 @@
+
+;
+; Implementation of TALK commands.
+; For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_TALK:
+
+	jsr dos_ENTER
+
+	and #$1F
+	beq msg_TALK_fail        ; branch if device 0 (used to denote lack of device)
+
+	cmp UNIT_SDCARD
+	bne @1
+
+	; TALK on SD card
+
+	lda #$00
+	bra msg_TALK_success
+@1:
+	cmp UNIT_FLOPPY
+	bne @2
+
+	; TALK on floppy
+
+	lda #$01
+	bra msg_TALK_success
+@2:
+	cmp UNIT_RAMDISK
+	bne msg_TALK_fail
+
+	; TALK on ram disk
+
+	lda #$02
+	
+	; FALLTROUGH
+
+msg_TALK_success:
+
+	sta IDX1_TALKER
+	asl
+	sta IDX2_TALKER
+
+	jmp dos_EXIT
+
+msg_TALK_fail:
+
+	lda #K_ERR_DEVICE_NOT_FOUND
+
+	jmp dos_EXIT_A_SEC

src/dos_m65/msg_tksa.s

@@ -0,0 +1,22 @@
+
+;
+; Implementation of TKSA commands.
+; For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_TKSA:
+
+	jsr dos_ENTER
+
+	and #$0F                   ; support channels 0-15, like 1541 drive
+
+	ldx IDX1_TALKER
+	bmi msg_TKSA_done          ; do nothing if no taalker
+	sta XX_CHANNEL, x          ; store channel
+
+	; FALLTROUGH
+
+msg_TKSA_done:
+
+	jmp dos_EXIT

src/dos_m65/msg_unlsn_untlk.s

@@ -0,0 +1,25 @@
+
+;
+; Implementation of UNLSN/UNTLK messages.
+; For detailed description see 'm65dos_bridge.s' file.
+;
+
+
+msg_UNLSN:
+
+	jsr dos_ENTER
+
+	lda #$FF
+	sta IDX1_LISTENER
+	sta IDX2_LISTENER
+
+	jmp dos_EXIT
+
+msg_UNTLK:
+
+	jsr dos_ENTER
+
+	sta IDX1_TALKER
+	sta IDX2_TALKER
+
+	jmp dos_EXIT