generally remove some debug output, add missing file, and make KERNAL LOAD routine more complete.

c64/kernal/iec_assert_atn.s

@@ -1,6 +1,4 @@
 iec_assert_atn:
-	jsr printf
-	.byte "ASSERT ATN",$0d,0
 	lda $dd00
 	ora #$08
 	sta $dd00

c64/kernal/iec_release_atn.s

@@ -1,6 +1,4 @@
 iec_release_atn:
-	jsr printf
-	.byte "RELEASE ATN",$0d,0
 	lda $dd00
 	and #$f7
 	sta $dd00

c64/kernal/iec_rx_byte.s

@@ -5,19 +5,13 @@
 
 iec_rx_byte:
 
-	inc $062f
-	
 	;; First, we wait for the talker to release the CLK line.
 	jsr iec_wait_for_clock_release
 
-	inc $0630
-	
 	;; We then release the data line
 	;; (We can use this routine, since we weren't holding CLK, anyway)
 	jsr iec_release_clk_and_data
 
-	inc $0631
-	
 	;; Wait for talker to assert CLK.
 	;; If >200usec, then it is EOI and we have to assert the
 	;; DATA line for 60 usec to tell the TALKER that we have
@@ -99,8 +93,6 @@ iec_rx_bit_loop:
 	dex
 	bpl iec_rx_bit_loop
 
-	inc $0637
-	
 	;; Then we must within 1000usec acknowledge the frame by
 	;; asserting DATA. At this point, CLK is asserted by the
 	;; talker and DATA by us, i.e., we are ready to receive

c64/kernal/iec_turnaround_to_listen.s

@@ -5,14 +5,12 @@ iec_turnaround_to_listen:
 
 	;; Assert data and release clock
 	lda $dd00
-	sta $0420
 	and #$ef		; release clock (bit 4)
 	ora #$20     		; assert data (bit 5)
 	sta $dd00
 	
 	;; Wait for clock line to be asserted by the drive
 *	lda $dd00
-	sta $0421
 	and #$40
 	bne -
 
@@ -36,8 +34,6 @@ iec_turnaround_to_listen:
 	;; sec
 	;; rts
 *
-	jsr printf
-	.byte "TURNAROUND SUCEEDED",$0d,$00
 
 	;; ATN turn around successful
 	clc

c64/kernal/iec_tx_byte.s

@@ -2,13 +2,6 @@ iec_tx_byte:
 
 	pha
 
-	sta $0400
-	
-	jsr printf
-	.byte "IEC TX BYTE $"
-	.byte $f0, <$0400,>$0400
-	.byte $0d,0
-
 	jsr iec_assert_clk_release_data
 
 	;; Give devices time to respond
@@ -16,12 +9,10 @@ iec_tx_byte:
 
 	;; Did a device respond? (DATA will be pulled if so)
 	lda $DD00
-	sta $0418
 	bpl +
 
 	;; No devices present, so we can immediately return with device not found
 	pla
-	inc $420
 	jmp kernalerror_DEVICE_NOT_FOUND
 *
 
@@ -87,12 +78,10 @@ iec_tx_byte_l1:
 	bne -
 
 	;; Timeout - DEVICE NOT PRESENT
-	inc $421
 	jmp kernalerror_DEVICE_NOT_FOUND
 *
 	;; All done.
 	;; End state is TALKER is asserting CLK, and listener is asserting DATA
 	;; until they are ready for the next byte.
-	inc $044f
 	clc
 	rts

c64/kernal/load.s

@@ -5,6 +5,9 @@ load:
 	;; Disable IRQs, since timing matters!
 	SEI
 
+	;; Display SEARCHING FOR
+	jsr printf
+	.byte "SEARCHING FOR <INSERT FILENAME HERE>",$0d,$0
 
 	;; Begin sending under attention
 	jsr iec_assert_atn
@@ -84,9 +87,6 @@ load:
 	beq -
 
 load_done:
-	jsr printf
-	.byte "LOADED",$0d,0
-
 	;; Close file on drive
 
 	;; Command drive to listen and to close the file

c64/kernal/printf.s

@@ -0,0 +1,158 @@
+	;; printf()-like routine for simplifying debugging
+
+	;; Prints the literal zero-terminated string that follows,
+	;; which may also include special tokens that allow
+	;; printing of hex byte and word values stored at the indicated
+	;; addresses.
+
+	;; .byte 1,$byte = display byte as hex
+	;; .byte 2,$low,$hi = display word as hex
+	;; .byte $f0+n,$low,$hi = display byte at $hi$lo+n as hex
+
+printf:
+	;; Temporary storage is between end of screen at $0400
+	;; and the sprite pointers at $7f8
+	sta $7f0
+	stx $7f1
+	sty $7f2
+	php
+	pla
+	sta $7f3
+
+	;; Set up read routine
+	lda #$ad 		; LDA $nnnn
+	sta $7f4
+	lda #$60
+	sta $7f7		; RTS
+	
+	;; Get PC of caller from the stack, so that
+	;; we can parse through it
+	pla
+	clc
+	adc #$01
+	sta $7f5
+	pla
+	adc #$00
+	sta $7f6
+
+printf_loop:
+	jsr $7f4
+	cmp #$00
+	bne printf_continues
+	;; Put return address on stack and restore
+	;; registers
+	lda $7f6
+	pha
+	lda $7f5
+	pha
+	lda $7f3
+	pha
+	lda $7f0
+	ldx $7f1
+	ldy $7f2
+	plp
+	rts
+
+printf_continues:
+	cmp #$01
+	bne not_hexbyte
+	;; Print a hex byte
+
+	;; Skip the token
+	jsr printf_advance
+	;; Read the low byte
+	jsr $7f4
+	;; Print as hex
+	jsr printf_printhexbyte
+	jmp printf_nextchar
+	
+not_hexbyte:
+	cmp #$02
+	bne not_hexword
+	;; Print a hex word
+
+	;; Skip the token
+	jsr printf_advance
+	jsr printf_advance
+	;; Read the high byte
+	jsr $7f4
+	;; Print as hex
+	jsr printf_printhexbyte
+	;; Skip the token
+	jsr printf_retreat
+	;; Read the low byte
+	jsr $7f4
+	;; Print as hex
+	jsr printf_printhexbyte
+	jsr printf_advance
+	jmp printf_nextchar
+	
+not_hexword:
+	cmp #$f0
+	bcc not_pointer
+
+	;; Treat two-byte arg as base address
+	;; and lower 4 bits of token as offset from
+	;; that location.
+
+	;; Get offset
+	and #$0f
+	tay
+
+	jsr printf_advance
+	jsr $7f4
+	sta $fd
+	jsr printf_advance
+	jsr $7f4
+	sta $fe
+
+	lda ($fd),y
+	jsr printf_printhexbyte
+	jmp printf_nextchar
+
+not_pointer:	
+	;; Print character
+	jsr $ffd2
+
+printf_nextchar:
+	jsr printf_advance
+
+	jmp printf_loop
+
+printf_advance:
+	;; Advance pointer to next character
+	inc $7f5
+	bne +
+	inc $7f6
+	*
+	rts
+
+printf_retreat:
+	;; Retreat pointer to previous char
+	lda $7f5
+	sec
+	sbc #1
+	sta $7f5
+	lda $7f6
+	sbc #0
+	sta $7f6
+	rts
+
+printf_printhexbyte:
+	pha
+	lsr
+	lsr
+	lsr
+	lsr
+	ora #$30
+	cmp #$3A
+	bcc +
+	adc #6
+*	jsr $ffd2
+	pla
+	and #$0f
+	ora #$30
+	cmp #$3A
+	bcc +
+	adc #6
+*	jmp $ffd2

src/compress_text.c

@@ -159,7 +159,7 @@ char *error_list[]={
   "LOAD",                  // https://www.discogs.com/Gimmik-Load-Error/release/482462
   // Non-error messages
   "READY.\r", // #29       // https://www.ibm.com/support/knowledgecenter/zosbasics/com.ibm.zos.zconcepts/zconc_whatistsonative.htm https://github.com/stefanhaustein/expressionparser
-  "LOADING",               // https://community.tibco.com/wiki/how-show-loading-prompt-when-reloading-external-data
+  "LOADING", // #30              // https://community.tibco.com/wiki/how-show-loading-prompt-when-reloading-external-data
   "VERIFYING",             // https://discussions.apple.com/thread/8087203
   "SAVING",
   "ERROR", // #33            // Simply the word error that is attached to the other parts of messages https://fjkraan.home.xs4all.nl/comp/apple2faq/app2asoftfaq.html