refactored LOAD routine so that it's parts are reuseable

c64/kernal/load.s

@@ -19,7 +19,7 @@
 
 	;; Searching through Compute's Mapping the 64, we find the following
 	;; things are used:
-	;; $93 = kernal_load_or_verify_flag
+	;; $93 = VERCK
 	;; $AC = current pointer for loading/verifying
 	;; $C1 = similar to the above.
 
@@ -30,11 +30,11 @@
 load:
 
 	;; Are we loading or verifying?
-	sta kernal_load_or_verify_flag
+	sta VERCK
 
 	;; Store start address of LOAD
-	stx load_save_start_ptr+0
-	sty load_save_start_ptr+1
+	stx STAL+0
+	sty STAL+1
 
 	;; Reset status
 	jsr kernalstatus_reset
@@ -43,21 +43,8 @@ load:
 	jsr install_ram_routines
 
 	;; Display SEARCHING FOR + filename
-	lda MSGFLG
-	bpl +
-	jsr printf
-	.byte $0D,"SEARCHING FOR ",0
-	ldy #$00
-print_filename_loop:
+	jsr lvs_display_searching_for
 
-	cpy current_filename_length
-	beq +
-	ldx #<current_filename_ptr
-	jsr peek_under_roms
-	jsr JCHROUT
-	iny
-	jmp print_filename_loop
-*
 	;; http://www.zimmers.net/anonftp/pub/cbm/programming/serial-bus.pdf
 	;; p13, 16; also p16 tells us this routine doesn't mess with the file table
 	;; in the C64, only in the drive.
@@ -65,21 +52,21 @@ print_filename_loop:
 	;; Call device to LISTEN (p16)
 	lda current_device_number
 	jsr listen
-	bcs load_device_not_found_error
+	bcs lvs_device_not_found_error
 
 	;; Open channel #0 (p16)
 	lda #$00
 	jsr tksa
-	bcs load_error
-	
+	bcs lvs_load_verify_error
+
 	;; Send filename (p16)
 	ldy #0
 
-send_filename:
+load_send_filename:
+
+	cpy FNLEN
+	beq load_filename_sent
 
-	cpy current_filename_length
-	beq sent_filename
-	
 	ldx #<current_filename_ptr
 	jsr peek_under_roms
 	iny
@@ -90,7 +77,7 @@ send_filename:
 	pha
 
 	;; Set Carry flag on the last file name character, to mark EOI
-	cmp current_filename_length
+	cmp FNLEN
 	clc
 	bne +
 	sec
@@ -100,108 +87,66 @@ send_filename:
 
 	pla
 	tay
-	jmp send_filename
+	jmp load_send_filename
 
-sent_filename:
+load_filename_sent:
 
 	;; Command device to unlisten to indicate end of file name. (p16)
 	jsr unlsn
-	bcs load_error
+	bcs lvs_load_verify_error
 	jsr iec_set_idle ;; XXX is it needed?
 
 	;; Now command device to talk (p16)
 	lda current_device_number
 	jsr talk
-	bcs load_error
+	bcs lvs_load_verify_error
 
 	lda #$60 ; open channel / data (p3) , required according to p13
 	jsr iec_tx_command
-	bcs load_error
+	bcs lvs_load_verify_error
 
 	;; We are currently talker, so do the IEC turn around so that we
 	;; are the listener (p16)
 	jsr iec_turnaround_to_listen
-	bcs load_error
+	bcs lvs_load_verify_error
 
 	;; Get load address and store it if secondary address is zero
 	jsr iec_rx_byte
-	bcs load_file_not_found_error
+	bcs lvs_file_not_found_error
 	ldx current_secondary_address
 	beq +
-	sta load_save_start_ptr+0
+	sta STAL+0
 *
 	jsr iec_rx_byte
-	bcs load_file_not_found_error
+	bcs lvs_file_not_found_error
 	ldx current_secondary_address
 	beq +
-	sta load_save_start_ptr+1
+	sta STAL+1
 *
-	;; Display LOADING / VERIFYING and start address
-	lda MSGFLG
-	bpl load_loop
-	lda kernal_load_or_verify_flag
-	beq +
-	jsr printf
-	.byte $0D, "VERIFYING", 0
-	jmp load_print_start_addr
-*
-	jsr printf
-	.byte $0D, "LOADING", 0
-load_print_start_addr:
-	jsr printf
-	.byte " FROM $",0
-	lda load_save_start_ptr+1
-	jsr printf_printhexbyte
-	lda load_save_start_ptr+0
-	jsr printf_printhexbyte
-	
+	;; Display start address
+	jsr lvs_display_loading_verifying
+
 load_loop:
 	;; We are now ready to receive bytes
 	jsr iec_rx_byte
-	bcs load_error
+	bcs lvs_load_verify_error
 
-	;; Save it and advance pointer.
-	;; As with our BASIC, we want to enable LOADing
-	;; anywhere in memory, including over the IO space.
-	;; Thus we have to use a helper routine in low memory
-	;; to do the memory access
+	;; Handle the byte (store in memory / verify)
+	jsr lvs_handle_byte_load_verify
+	bcs lvs_load_verify_error
+	
+	;; Advance pointer to data
+	jsr lvs_advance_pointer
+	bcs lvs_wrap_around_error
 
-	;; Save byte under ROMs and IO if required
-	php
-	sei
-	ldx #$33
-	stx $01
-	ldy #0
-	sta (load_save_start_ptr),y
-	ldx #$37
-	stx $01
-	plp
-
-	;; Advance pointer
-	inc load_save_start_ptr
-	bne +
-	inc load_save_start_ptr+1
-	;; If we wrap around to $0000, then this is bad.
-	beq load_wrap_around_error
-*
 	;; Check for EOI - if so, this was the last byte
 	lda IOSTATUS
 	and #K_STS_EOI
 	beq load_loop
 
-load_done:
 	;; Display end address
-	lda MSGFLG
-	bpl +
-	jsr printf
-	.byte " TO $",0
-	lda load_save_start_ptr+1
-	jsr printf_printhexbyte
-	lda load_save_start_ptr+0
-	jsr printf_printhexbyte
-	lda #$0D
-	jsr JCHROUT
-*
+	jsr lvs_display_done
+
 	;; Close file on drive
 
 	;; Command drive to stop talking and to close the file
@@ -214,7 +159,7 @@ load_done:
 	lda current_device_number
 	jsr listen
 
-	lda #$e0
+	lda #$E0
 	jsr iec_tx_command
 
 	;; Tell drive to unlisten
@@ -223,41 +168,5 @@ load_done:
 	;; Set IEC status back to idle
 	jsr iec_set_idle
 
-	;; Return last address - Compute's Mapping the 64 says without the '+1',
-	;; checked (short test program) on original ROMs that this is really the case
-	ldx load_save_start_ptr+0
-	ldy load_save_start_ptr+1
-
-	clc
-	rts
-
-load_wrap_around_error:
-
-	;; This error is probably not even detected by C64 Kernal;
-	;; report BASIC error code that looks the most sane
-	lda #B_ERR_OVERFLOW
-	sec
-	rts
-
-load_device_not_found_error:
-
-	jsr kernalstatus_DEVICE_NOT_FOUND
-	jmp kernalerror_DEVICE_NOT_FOUND
-
-load_file_not_found_error:
-
-	jmp kernalerror_FILE_NOT_FOUND
-
-load_error:
-
-	;; XXX should we really return BASIC error code here?
-	lda kernal_load_or_verify_flag
-	beq load_verify_error
-	lda #B_ERR_LOAD
-	bne +
-load_verify_error:
-	lda #B_ERR_VERIFY
-*	
-	sec
-	rts
-
+	;; Return last address
+	jmp lvs_return_last_address