finished OPEN routine, some IEC cleanups

STATUS.md

@@ -88,7 +88,7 @@ NOTE: Even the 'DONE' routines won't support features described as missing in on
 | $FFB7   | READST | DONE     |                                               |
 | $FFBA   | SETFLS | DONE     |                                               |
 | $FFBD   | SETNAM | DONE     |                                               |
-| $FFC0   | OPEN   | PARTIAL  | * work in progress                            |
+| $FFC0   | OPEN   | DONE     |                                               |
 | $FFC3   | CLOSE  | DONE     |                                               |
 | $FFC6   | CHKIN  | DONE     |                                               |
 | $FFC9   | CHKOUT | PARTIAL  |                                               |

c64/kernal/chkinout.s

@@ -42,7 +42,7 @@ chkin:
 
 	;; For IEC devices, send TALK + TKSA first
 	lda FAT,Y
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs chkin_set_device
 
 	jsr talk
@@ -125,7 +125,7 @@ ckout:
 
 	;; For IEC devices, send LISTEN + SECOND first
 	lda FAT,Y
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs chkin_set_device
 
 	jsr listen

c64/kernal/chrin.s

@@ -21,7 +21,7 @@ chrin:
 	beq chrin_keyboard ; #$00 - keyboard
 	;; XXX add screen support
 
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs chrin_done_fail ; not a supported device
 
 chrin_iec:

c64/kernal/chrout.s

@@ -27,16 +27,44 @@ chrout:
 
 	cmp #$03 ; screen
 	beq chrout_screen
-	
+
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs chrout_done_fail ; not a supported device
 
 chrout_iec:
 
 	lda last_printed_character_ascii
 	jsr JCIOUT
-	bcs chrout_done_fail
+	bcc chrout_done
-	jmp chrout_done
+	
+	;; FALLTROUGH
+
+chrout_done_fail:
+	jsr show_cursor_if_enabled
+	
+	plp
+	
+	;; Restore X and Y, set carry to mark success on exit
+	pla
+	tay
+	pla
+	tax
+	sec ; indicate failure
+	rts
+
+chrout_done:
+	jsr show_cursor_if_enabled
+	
+	plp
+	
+	;; Restore X and Y, set carry to mark success on exit
+	pla
+	tay
+	pla
+	tax
+	lda last_printed_character_ascii
+	clc ; indicate success
+	rts
 
 chrout_screen:
 
@@ -399,33 +427,7 @@ not_quote:
 	sta current_screen_x
 	jmp screen_advance_to_next_line
 no_screen_advance_to_next_line:
-
+	jmp chrout_done
-chrout_done:
-	jsr show_cursor_if_enabled
-	
-	plp
-	
-	;; Restore X and Y, set carry to mark success on exit
-	pla
-	tay
-	pla
-	tax
-	lda last_printed_character_ascii
-	clc ; indicate success
-	rts
-
-chrout_done_fail:
-	jsr show_cursor_if_enabled
-	
-	plp
-	
-	;; Restore X and Y, set carry to mark success on exit
-	pla
-	tay
-	pla
-	tax
-	sec ; indicate failure
-	rts
 
 screen_grow_logical_line:
 	ldy current_screen_y

c64/kernal/close.s

@@ -20,7 +20,7 @@ close:
 
 	;; We have the entry index in Y - check whether this is IEC device
 	lda FAT, y
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs close_remove_from_table
 
 	;; IEC device

c64/kernal/clrchn.s

@@ -13,14 +13,14 @@ clrchn:
 
 	;; Handle IEC input device
 	lda DFLTN
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs +
 	;; Previous device was IEC one - send UNTALK first
 	jsr untlk
 *
 	;; Restore output device to default
 	lda DFLTO
-	jsr iec_devnum_check
+	jsr iec_check_devnum
 	bcs +
 	;; Handle IEC output device
 	jsr unlsn

c64/kernal/iec/iec_check_devnum.s

@@ -1,22 +1,22 @@
 
 ;;
-;; Checks whether device numbe (in .A) is a correct IEC device number
+;; Checks whether device number (in .A) is a correct IEC device number
 ;;
 ;; Preserves .A, .X and .Y
 ;;
 
-iec_devnum_check:
+iec_check_devnum:
 	;; 0, 1, 2, or 3 are illegal - reserved for non-IEC devices on Commodore
 	cmp #$04
 	bcs +
 	;; FALLTROUGH
-iec_devnum_check_failed:
+iec_check_devnum_failed:
 	sec ; indicate non-IEC device
 	rts
 *
 	;; 31 and above are illegal too, due to IEC command encoding scheme,
 	;; see https://www.pagetable.com/?p=1031
 	cmp #$1F
-	bcs iec_devnum_check_failed
+	bcs iec_check_devnum_failed
 	;; Carry is clear here - indicates IEC device
 	rts

c64/kernal/iec/iec_cmd_close.s

@@ -0,0 +1,20 @@
+
+;;
+;; Kernal internal IEC routine
+;;
+;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
+;;
+
+iec_cmd_close:
+
+	jsr iec_tx_flush
+
+	;; Due to OPEN/CLOSE/TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
+	;; allowed channels are 0-15; report error if out of range
+	cmp #$10
+	bcc + 
+	jmp kernalerror_FILE_NOT_INPUT
+*
+	ora #$E0
+
+	jmp common_open_close_unlsn_second

c64/kernal/iec/iec_cmd_open.s

@@ -0,0 +1,29 @@
+
+;;
+;; Kernal internal IEC routine
+;;
+;; - https://www.pagetable.com/?p=1031, https://github.com/mist64/cbmbus_doc
+;;
+
+
+iec_cmd_open: ; similar to TKSA, but without turnaround
+
+	;; Due to OPEN/CLOSE/TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
+	;; allowed channels are 0-15; report error if out of range
+	cmp #$10
+	bcc + 
+	jmp kernalerror_FILE_NOT_INPUT
+*
+	ora #$F0
+
+	;; FALLTROUGH
+
+common_open_close_unlsn_second: ; common part of several commands
+
+	sta IEC_TMP2
+	jsr iec_tx_command
+	bcs + ; branch if error
+	jmp iec_tx_command_finalize
+*
+	rts
+

c64/kernal/listen.s

@@ -17,9 +17,10 @@ listen:
 	jsr iec_tx_flush
 
 	;; Check whether device number is correct
-	jsr iec_devnum_check
+	jsr iec_check_devnum
-	bcs kernalerror_DEVICE_NOT_FOUND
+	bcc +
-
+	jmp kernalerror_DEVICE_NOT_FOUND
+*
 	;; Encode and execute the command
 	ora #$20
 

c64/kernal/load.s

@@ -62,42 +62,13 @@ load:
 	jsr listen
 	bcs lvs_device_not_found_error
 
-	;; Open channel #0 (p16)
+	;; Open channel 0 (reserved for file reading)
-	lda #$F0 ; $F0 for TKSA + 0 for channel number
+	lda #$00
-	sta IEC_TMP2
+	jsr iec_cmd_open
-	jsr iec_tx_command
-	bcs lvs_load_verify_error
-	jsr iec_tx_command_finalize
 	bcs lvs_load_verify_error
 
-	;; Send filename (p16)
+	;; Send file name
-	ldy #0
+	jsr lvs_send_file_name
-
-load_send_filename:
-
-	cpy FNLEN
-	beq load_filename_sent
-
-	ldx #<current_filename_ptr
-	jsr peek_under_roms
-	iny
-
-	;; Set Carry flag on the last file name character, to mark EOI
-	cpy FNLEN
-	clc
-	bne +
-	sec
-*
-	;; Transmit one character
-	sta IEC_TMP2
-	jsr iec_tx_byte
-
-	jmp load_send_filename
-
-load_filename_sent:
-
-	;; Command device to unlisten to indicate end of file name. (p16)
-	jsr unlsn
 	bcs lvs_load_verify_error
 
 	;; Now command device to talk (p16)

c64/kernal/lvs_helpers.s

@@ -3,6 +3,28 @@
 ;; Helper functions for various LOAD/VERIVY/SAVE routine variants (IEC / U64 / etc.)
 ;;
 
+lvs_send_file_name:
+	ldy #0
+lvs_send_file_name_loop:
+	cpy FNLEN
+	beq lvs_send_file_name_done
+	ldx #<current_filename_ptr
+	jsr peek_under_roms
+	iny
+	;; Set Carry flag on the last file name character, to mark EOI
+	cpy FNLEN
+	clc
+	bne +
+	sec
+*
+	;; Transmit one character
+	sta IEC_TMP2
+	jsr iec_tx_byte
+	jmp lvs_send_file_name_loop
+lvs_send_file_name_done:
+	jsr unlsn
+	rts
+
 lvs_handle_byte_load_verify:
 
 	;; XXX add VERIFY support

c64/kernal/open.s

@@ -8,7 +8,6 @@
 ;; CPU registers that has to be preserved (see [RG64]): none
 ;;
 
-;; XXX send the name to the drive (if it's length is non-zero)
 
 open:
 
@@ -51,7 +50,37 @@ open_has_space:
 
 	iny
 	sty LDTND
+
+	;; Check for command to send
+	lda FNLEN
+	beq open_done_success
 	
+	;; Check for IEC device
+	lda current_device_number
+	jsr iec_check_devnum
+	bcc open_iec
+
+	;; FALLTROUGH
+open_done_success:
+
 	clc
 	rts
 
+open_iec:
+
+	;; We have a command to send to IEC device
+	jsr listen
+	bcc +
+	jmp kernalerror_DEVICE_NOT_FOUND
+*
+	lda current_secondary_address
+	jsr iec_cmd_open
+	bcc +
+	jmp kernalerror_DEVICE_NOT_FOUND ; XXX find a better error message for wrong channel (create new one?)
+*
+	;; Send command ('file name')
+	jsr lvs_send_file_name
+
+	jmp open_done_success
+
+

c64/kernal/second.s

@@ -12,12 +12,14 @@
 
 second:
 
-	;; Due to TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
+	;; Due to OPEN/CLOSE/TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
 	;; allowed channels are 0-15; report error if out of range
 	cmp #$10
-	bcs kernalerror_FILE_NOT_INPUT
+	bcc + 
-
+	jmp kernalerror_DEVICE_NOT_FOUND ; XXX find a better error message for wrong channel (create new one?)
+*
 	ora #$60
 
-	jmp common_unlsn_second
+	jmp common_open_close_unlsn_second
+
 

c64/kernal/talk.s

@@ -17,9 +17,10 @@ talk:
 	jsr iec_tx_flush
 
 	;; Check whether device number is correct
-	jsr iec_devnum_check
+	jsr iec_check_devnum
-	bcs kernalerror_DEVICE_NOT_FOUND
+	bcc +
-
+	jmp kernalerror_DEVICE_NOT_FOUND
+*
 	;; Encode and execute the command
 	ora #$40
 

c64/kernal/tksa.s

@@ -12,11 +12,12 @@
 
 tksa:
 
-	;; Due to TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
+	;; Due to OPEN/CLOSE/TKSA/SECOND command encoding (see https://www.pagetable.com/?p=1031),
 	;; allowed channels are 0-15; report error if out of range
 	cmp #$10
-	bcs kernalerror_FILE_NOT_INPUT
+	bcc + 
-
+	jmp kernalerror_DEVICE_NOT_FOUND ; XXX find a better error message for wrong channel (create new one?)
+*
 	ora #$F0
 
 	jmp common_untlk_tksa

c64/kernal/unlsn.s

@@ -19,13 +19,7 @@ unlsn:
 	;; Buffer empty, send the command
 	lda #$3F
 
-common_unlsn_second: ; common part of UNSLS and SECOND
+	jmp common_open_close_unlsn_second
 
-	sta IEC_TMP2
-	jsr iec_tx_command
-	bcs + ; branch if error
-	jmp iec_tx_command_finalize
-*
-	rts