work towards Ultimate 64 LOAD support

c64/kernal/,platform_generic/,hooks_generic.s

@@ -0,0 +1,6 @@
+
+;; Platform-specific hooks
+
+
+.macro PLATFORM_HOOK_LOAD
+.macend

c64/kernal/,platform_mega65/,hooks_mega65.s

@@ -0,0 +1,6 @@
+
+;; Platform-specific hooks
+
+
+.macro PLATFORM_HOOK_LOAD
+.macend

c64/kernal/,platform_ultimate64/,aliases_ultimate64.s

@@ -1,10 +1,57 @@
 
-;; Registers according to Ultimate 64 Command Interface ddescription,
+;; Registers according to Ultimate 64 Command Interface description,
 ;; https://1541u-documentation.readthedocs.io/en/latest/command%20interface.html
+;; and ultimate_dos_v1.0.pdf and command_interface_v1.0.pdf by Gideon Zweijtzer
 
-	.alias U64_CONTROL           $DF1C ; write
-	.alias U64_STATUS            $DF1C ; read
-	.alias U64_COMMAND_DATA      $DF1D ; write
-	.alias U64_IDENTIFICATION    $DF1D ; read
-	.alias U64_RESPONSE_DATA     $DF1E ; read only
-	.alias U64_STATUS_DATA       $DF1F ; read only
+	;; Command interface registers
+	.alias U64_CONTROL                 $DF1C ; write
+	.alias U64_STATUS                  $DF1C ; read
+	.alias U64_COMMAND_DATA            $DF1D ; write
+	.alias U64_IDENTIFICATION          $DF1D ; read
+	.alias U64_RESPONSE_DATA           $DF1E ; read only
+	.alias U64_STATUS_DATA             $DF1F ; read only
+
+	;; Constant for U64_IDENTIFICATION register
+	.alias U64_MAGIC_ID                $C9
+
+	;; Constants for U64_CONTROL register
+	.alias U64_CTRL_BIT_PUSH_CMD       $01
+	.alias U64_CTRL_BIT_DATA_ACC       $02
+	.alias U64_CTRL_BIT_ABORT          $04
+	.alias U64_CTRL_BIT_CLR_ERR        $08
+
+	;; Constants for U64_STATUS register
+	.alias U64_STAT_BIT_CMD_BUSY       $01
+	.alias U64_STAT_BIT_DATA_ACC       $02
+	.alias U64_STAT_BIT_ABORT_P        $04
+	.alias U64_STAT_BIT_ERROR          $08
+	.alias U64_STAT_MASK_STATE         $30 ; two bits!
+	.alias U64_STAT_BIT_STAT_AV        $40
+	.alias U64_STAT_BIT_DATA_AV        $80
+
+	;; Interface targets
+	.alias U64_TARGET_DOS1             $01
+	.alias U64_TARGET_DOS2             $02
+
+	;; DOS command codes
+	.alias U64_DOS_CMD_IDENTIFY        $01
+	.alias U64_DOS_CMD_OPEN_FILE       $02
+	.alias U64_DOS_CMD_CLOSE_FILE      $03
+	.alias U64_DOS_CMD_READ_DATA       $04
+	.alias U64_DOS_CMD_WRITE_DATA      $05
+	.alias U64_DOS_CMD_FILE_SEEK       $06
+	.alias U64_DOS_CMD_FILE_INFO       $07
+	.alias U64_DOS_CMD_CHANGE_DIR      $11
+	.alias U64_DOS_CMD_GET_PATH        $12
+	.alias U64_DOS_CMD_OPEN_DIR        $13
+	.alias U64_DOS_CMD_READ_DIR        $14
+	.alias U64_DOS_CMD_COPY_UI_PATH    $15
+	.alias U64_DOS_CMD_LOAD_REU        $21
+	.alias U64_DOS_CMD_SAVE_REU        $22
+	.alias U64_DOS_CMD_ECHO            $F0
+
+	;; DOS file opening constants 
+	.alias U64_FA_READ                 $01
+	.alias U64_FA_WRITE                $02
+	.alias U64_FA_CREATE_NEW           $03
+	.alias U64_FA_CREATE_ALWAYS        $04

c64/kernal/,platform_ultimate64/,hooks_ultimate64.s

@@ -0,0 +1,7 @@
+
+;; Platform-specific hooks
+
+
+.macro PLATFORM_HOOK_LOAD
+	jsr u64_load
+.macend

c64/kernal/,platform_ultimate64/u64_load.s

@@ -0,0 +1,140 @@
+
+;;
+;; LOAD routine hook for fast loading via UltiDOS
+;;
+
+
+u64_load:
+
+	jsr printf
+	.byte "DGB: 0",$0D,0 
+
+	;; First check whether the command interface is enabled
+	;; XXX identification does not work, why?
+	;; lda U64_IDENTIFICATION
+	;; cmp U64_MAGIC_ID
+	;; beq +
+
+u64_load_skip:
+	;; rts
+*
+	jsr printf
+	.byte "DGB: 1",$0D,0 
+
+	;; XXX find out which device number softIEC is mapped to
+	lda current_device_number
+	cmp #$20 ; for now use device number 32
+	beq u64_load_skip
+
+	.byte "DGB: 2",$0D,0
+	
+	;; Takeover the flow completely
+	pla
+	pla
+
+	;; Display SEARCHING FOR + filename
+	jsr lvs_display_searching_for
+
+	.byte "DGB: 3",$0D,0
+
+	;; Whatever the interface was doing - ask to abort it
+	jsr u64_load_abort
+
+	.byte "DGB: 4",$0D,0
+	
+	;; Send a command to open the file
+	lda #U64_DOS_CMD_OPEN_FILE
+	jsr u64_load_send_cmd
+	lda #U64_FA_READ
+	jsr u64_load_send_cmd
+	jsr u64_load_send_filename
+	jsr u64_load_finalize_cmd
+
+	.byte "DGB: 5",$0D,0
+	
+	;; Check status
+	jsr u64_load_check_status
+	bcs lvs_file_not_found_error
+
+	;; Load first two bytes to determine start address
+
+	;; XXX
+	
+	.byte "DGB: 6",$0D,0
+
+	jmp lvs_wrap_around_error
+	rts
+
+u64_load_abort:
+	lda #U64_CTRL_BIT_ABORT
+	sta U64_CONTROL
+*
+	lda U64_STATUS
+	bne -
+	rts
+
+u64_load_send_cmd:
+
+	ldx #U64_TARGET_DOS2
+	stx U64_COMMAND_DATA ; target
+	sta U64_COMMAND_DATA ; command code
+	rts
+
+u64_load_send_filename:
+	ldy #0
+u64_load_send_filename_loop:
+	cpy FNLEN
+	bne+
+	rts
+*
+	ldx #<current_filename_ptr
+	jsr peek_under_roms
+	iny
+	
+	sta U64_COMMAND_DATA
+	jmp u64_load_send_filename_loop
+
+u64_load_finalize_cmd:
+	;; Push the command for execution
+	lda #U64_CTRL_BIT_PUSH_CMD
+	sta U64_CONTROL
+	;; Wait till it is complete
+*
+	lda U64_STATUS
+	and #U64_STAT_BIT_CMD_BUSY
+	bne -
+	rts
+
+u64_load_check_status:
+	;; Wait till status is available
+	lda U64_STATUS
+	and #U64_STAT_BIT_STAT_AV
+	beq u64_load_check_status
+	
+	;; Status is ready - check the first character
+	lda U64_STATUS_DATA
+	cmp #$30 ; '0'
+	bne u64_load_check_status_wrong
+	
+	;; Check the second status character
+	lda U64_STATUS
+	and #U64_STAT_BIT_STAT_AV
+	beq u64_load_check_status_ok
+	lda U64_STATUS_DATA
+	cmp #$30 ; '0'
+	beq u64_load_check_status_ok
+	;; FALLTROUGH
+u64_load_check_status_wrong:
+	sec
+	bcs +
+u64_load_check_status_ok:
+	clc
+*
+	;; Now empty the status queue
+	lda U64_STATUS
+	and #U64_STAT_BIT_STAT_AV
+	beq +
+	lda U64_STATUS_DATA
+	jmp -
+*
+	rts

c64/kernal/load.s

@@ -17,14 +17,7 @@
 	;; On exit, $YYXX is the highest address into which data
 	;; will have been placed.
 
-	;; Searching through Compute's Mapping the 64, we find the following
-	;; things are used:
-	;; $93 = VERCK
-	;; $AC = current pointer for loading/verifying
-	;; $C1 = similar to the above.
-
-	;; XXX honor MSGFLG bit 6, add VERIFY support
-	;; XXX rework the message print-out to be shared with SAVE
+	;; XXX honor MSGFLG bit 6
 	;; XXX add VERIFY support
 
 load:
@@ -42,6 +35,9 @@ load:
 	;; We need our helpers to get to filenames under ROMs or IO area
 	jsr install_ram_routines
 
+	;; Allow platform-specific routine to takeover the flow
+	`PLATFORM_HOOK_LOAD
+
 	;; Display SEARCHING FOR + filename
 	jsr lvs_display_searching_for
 

c64/kernal/lvs_helpers.s

@@ -5,6 +5,8 @@
 
 lvs_handle_byte_load_verify:
 
+	;; XXX add VERIFY support
+
 	;; Save it and advance pointer.
 	;; As with our BASIC, we want to enable LOADing
 	;; anywhere in memory, including over the IO space.