chiptune_player: split interrupt handler to own file

asm_routines/lz4_decode.s

@@ -36,7 +36,8 @@
 ;COUNT		EQU $06
 ;DELTA		EQU $08
 
-orgoff	EQU $5E00	; offset of first unpacked byte
+;UNPACK_BUFFER	EQU $5E00	; offset of first unpacked byte
+
 
 	;======================
 	; LZ4 decode
@@ -54,9 +55,9 @@ lz4_decode:
 	adc	LZ4_END+1
 	sta	LZ4_END+1
 
-	lda	#>orgoff		; original unpacked data offset
+	lda	#>UNPACK_BUFFER		; original unpacked data offset
 	sta	LZ4_DST+1
-	lda	#<orgoff
+	lda	#<UNPACK_BUFFER
 	sta	LZ4_DST
 
 unpmain:

chiptune_player/Makefile

@@ -33,7 +33,7 @@ chiptune_player.o:	chiptune_player.s \
 	../asm_routines/mockingboard.s \
 	../asm_routines/dos33_routines.s \
 	../asm_routines/lz4_decode.s \
-	rasterbars.s volume_bars.s \
+	rasterbars.s volume_bars.s interrupt_handler.s \
 	chip_title.inc zp.inc
 	ca65 -o chiptune_player.o chiptune_player.s -l chiptune_player.lst
 

chiptune_player/chiptune_player.s

@@ -3,7 +3,7 @@
 .include	"zp.inc"
 				; program is ~4k, so from 0xc00 to 0x1C00
 LZ4_BUFFER	EQU	$1C00		; $1C00 - $5C00, 16k for now
-CHUNK_BUFFER	EQU	$5E00		; $5E00 - $9600, 14k, $3800
+UNPACK_BUFFER	EQU	$5E00		; $5E00 - $9600, 14k, $3800
 					; trying not to hit DOS at $9600
 					; Reserve 3 chunks plus spare (14k)
 CHUNKSIZE	EQU	$3
@@ -126,9 +126,9 @@ mockingboard_found:
 	jsr	new_song
 
 
-	lda	#<CHUNK_BUFFER		; set input pointer
+	lda	#<UNPACK_BUFFER		; set input pointer
 	sta	INL
-	lda	#>CHUNK_BUFFER
+	lda	#>UNPACK_BUFFER
 	sta	INH
 
 
@@ -196,167 +196,8 @@ done_play:
 forever_loop:
 	jmp	forever_loop
 
-	;=============================
-	;=============================
-	; simple interrupt handler
-	;=============================
-	;=============================
-	; On Apple II/6502 the interrupt handler jumps to address in 0xfffe
-	; This is in the ROM, which saves the registers
-	;   on older IIe it saved A to $45 (which could mess with DISK II)
-	;   newer IIe doesn't do that.
-	; It then calculates if it is a BRK or not (which trashes A)
-	; Then it sets up the stack like an interrupt and calls 0x3fe
-
-interrupt_handler:
-	pha			; save A				; 3
-;	tya
-;	pha
-;	txa
-;	pha
-				; Should we save X and Y too?
-
-;	inc	$0404		; debug
-
-	bit	$C404		; clear 6522 interrupt by reading T1C-L	; 4
 
 
-								;============
-								;	  7
-	;=====================
-	; Update time counter
-	;=====================
-
-	inc	FRAME_COUNT						; 5
-	lda	FRAME_COUNT						; 3
-	cmp	#50							; 3
-	bne	frame_good						; 3/2nt
-
-	lda	#$0							; 2
-	sta	FRAME_COUNT						; 3
-
-update_second_ones:
-	inc	$7d0+17							; 6
-	inc	$bd0+17							; 6
-	lda	$bd0+17							; 4
-	cmp	#$ba			; one past '9'			; 2
-	bne	frame_good						; 3/2nt
-	lda	#'0'+$80						; 2
-	sta	$7d0+17							; 4
-	sta	$bd0+17							; 4
-update_second_tens:
-	inc	$7d0+16							; 6
-	inc	$bd0+16							; 6
-	lda	$bd0+16							; 4
-	cmp	#$b6		; 6 (for 60 seconds)			; 2
-	bne	frame_good						; 3/2nt
-	lda	#'0'+$80						; 2
-	sta	$7d0+16							; 4
-	sta	$bd0+16							; 4
-update_minutes:
-	inc	$7d0+14							; 6
-	inc	$bd0+14							; 6
-				; we don't handle > 9:59 songs yet
-
-								;=============
-								;     90 worst
-
-frame_good:
-
-	ldy	MB_FRAME_DIFF	; get chunk offset			; 3
-
-	ldx	#0		; set up reg count			; 2
-
-								;=============
-								;	5
-
-mb_write_loop:
-	lda	(INL),y		; load register value			; 5
-
-				; if REG==1 and high bit set
-				; then end of song
-
-	bpl	mb_not_done						; 3/2nt
-	cpx	#1							; 2
-	bne	mb_not_done						; 3/2nt
-
-	lda	#1		; set done playing			; 2
-	sta	DONE_PLAYING						; 3
-	jmp	done_interrupt						; 3
-
-mb_not_done:
-
-	; special case R13.  If it is 0xff, then don't update
-	; otherwise might spuriously reset the envelope settings
-
-	cpx	#13							; 2
-	bne	mb_not_13						; 3/2nt
-	cmp	#$ff							; 2
-	beq	skip_r13						; 3/2nt
-
-mb_not_13:
-	sta	MB_VALUE						; 3
-
-	; always write out all to zero page
-	; we mostly care about vola/volb/volc so this wastes 11 bytes of RAM
-	; code is simpler, and save on three cmp/branches per loop
-
-	and	#$f							; 2
-	sta	REGISTER_DUMP,X						; 4
-
-					; INLINE this (could save 72 cycles)
-	jsr	write_ay_both		; assume 3 channel (not six)	; 6
-					; so write same to both
-					; left/right
-									; 53
-
-	clc				; point to next interleaved	; 2
-	lda	INH			; page by adding $300		; 3
-	adc	#CHUNKSIZE						; 2
-	sta	INH							; 3
-
-	inx				; point to next register	; 2
-	cpx	#14			; if 14 we're done		; 2
-	bmi	mb_write_loop		; otherwise, loop		; 3/2nt
-								;============
-								; roughly 95?
-								;  *13= 1235?
-skip_r13:
-
-	inc	MB_FRAME_DIFF		; increment offset		; 5
-	bne	reset_chunk		; if not zero,	done		; 3/2nt
-
-wraparound:
-
-	inc	MB_CHUNK		; go to next chunk		; 5
-	lda	MB_CHUNK						; 3
-	cmp	#CHUNKSIZE		; have we reached end?		; 2
-	bne	reset_chunk						; 3/2nt
-	lda	#0			; if so reset			; 2
-	sta	MB_CHUNK						; 3
-
-	; can't tail call as need to restore stack and rti
-	jsr	next_subsong		; and decompress next		; 6
-
-
-reset_chunk:
-	lda	MB_CHUNK		; reset input pointer		; 3
-	clc				; to the beginning		; 2
-
-	adc	#>CHUNK_BUFFER		; in proper chunk (1 of 3)	; 2
-	sta	INH							; 3
-
-
-								;============
-								;        18
-done_interrupt:
-	pla			; restore a				; 4
-
-	rti			; return from interrupt			; 6
-
-								;============
-								; typical
-								; 1358 cycles
 
 	;=================
 	; load a new song
@@ -526,13 +367,13 @@ bloop22:
 	;	DST: chunk_buffer+$2A00+(COPY_OFFSET*256)
 page_copy:
 	clc								; 2
-	lda	#>(CHUNK_BUFFER+512)					; 3
+	lda	#>(UNPACK_BUFFER+512)					; 3
 	adc	COPY_OFFSET						; 3
 	adc	COPY_OFFSET						; 3
 	adc	COPY_OFFSET						; 3
 	sta	page_copy_loop+2			; self modify	; 5
 
-	lda	#>(CHUNK_BUFFER+$2A00)					; 2
+	lda	#>(UNPACK_BUFFER+$2A00)					; 2
 	adc	COPY_OFFSET						; 3
 	sta	page_copy_loop+5			; self modify	; 5
 
@@ -581,6 +422,7 @@ krw_file:
 .include	"../asm_routines/lz4_decode.s"
 .include	"rasterbars.s"
 .include	"volume_bars.s"
+.include	"interrupt_handler.s"
 
 ;=========
 ; strings

chiptune_player/interrupt_handler.s

@@ -0,0 +1,158 @@
+	;================================
+	;================================
+	; mockingboard interrupt handler
+	;================================
+	;================================
+	; On Apple II/6502 the interrupt handler jumps to address in 0xfffe
+	; This is in the ROM, which saves the registers
+	;   on older IIe it saved A to $45 (which could mess with DISK II)
+	;   newer IIe doesn't do that.
+	; It then calculates if it is a BRK or not (which trashes A)
+	; Then it sets up the stack like an interrupt and calls 0x3fe
+
+interrupt_handler:
+	pha			; save A				; 3
+				; Should we save X and Y too?
+
+;	inc	$0404		; debug
+
+	bit	$C404		; clear 6522 interrupt by reading T1C-L	; 4
+
+
+								;============
+								;	  7
+	;=====================
+	; Update time counter
+	;=====================
+
+	inc	FRAME_COUNT						; 5
+	lda	FRAME_COUNT						; 3
+	cmp	#50							; 3
+	bne	frame_good						; 3/2nt
+
+	lda	#$0							; 2
+	sta	FRAME_COUNT						; 3
+
+update_second_ones:
+	inc	$7d0+17							; 6
+	inc	$bd0+17							; 6
+	lda	$bd0+17							; 4
+	cmp	#$ba			; one past '9'			; 2
+	bne	frame_good						; 3/2nt
+	lda	#'0'+$80						; 2
+	sta	$7d0+17							; 4
+	sta	$bd0+17							; 4
+update_second_tens:
+	inc	$7d0+16							; 6
+	inc	$bd0+16							; 6
+	lda	$bd0+16							; 4
+	cmp	#$b6		; 6 (for 60 seconds)			; 2
+	bne	frame_good						; 3/2nt
+	lda	#'0'+$80						; 2
+	sta	$7d0+16							; 4
+	sta	$bd0+16							; 4
+update_minutes:
+	inc	$7d0+14							; 6
+	inc	$bd0+14							; 6
+				; we don't handle > 9:59 songs yet
+
+								;=============
+								;     90 worst
+
+frame_good:
+
+	ldy	MB_FRAME_DIFF	; get chunk offset			; 3
+
+	ldx	#0		; set up reg count			; 2
+
+								;=============
+								;	5
+
+mb_write_loop:
+	lda	(INL),y		; load register value			; 5
+
+				; if REG==1 and high bit set
+				; then end of song
+
+	bpl	mb_not_done						; 3/2nt
+	cpx	#1							; 2
+	bne	mb_not_done						; 3/2nt
+
+	lda	#1		; set done playing			; 2
+	sta	DONE_PLAYING						; 3
+	jmp	done_interrupt						; 3
+
+mb_not_done:
+
+	; special case R13.  If it is 0xff, then don't update
+	; otherwise might spuriously reset the envelope settings
+
+	cpx	#13							; 2
+	bne	mb_not_13						; 3/2nt
+	cmp	#$ff							; 2
+	beq	skip_r13						; 3/2nt
+
+mb_not_13:
+	sta	MB_VALUE						; 3
+
+	; always write out all to zero page
+	; we mostly care about vola/volb/volc so this wastes 11 bytes of RAM
+	; code is simpler, and save on three cmp/branches per loop
+
+	and	#$f							; 2
+	sta	REGISTER_DUMP,X						; 4
+
+					; INLINE this (could save 72 cycles)
+	jsr	write_ay_both		; assume 3 channel (not six)	; 6
+					; so write same to both
+					; left/right
+									; 53
+
+	clc				; point to next interleaved	; 2
+	lda	INH			; page by adding $300		; 3
+	adc	#CHUNKSIZE						; 2
+	sta	INH							; 3
+
+	inx				; point to next register	; 2
+	cpx	#14			; if 14 we're done		; 2
+	bmi	mb_write_loop		; otherwise, loop		; 3/2nt
+								;============
+								; roughly 95?
+								;  *13= 1235?
+skip_r13:
+
+	inc	MB_FRAME_DIFF		; increment offset		; 5
+	bne	reset_chunk		; if not zero,	done		; 3/2nt
+
+wraparound:
+
+	inc	MB_CHUNK		; go to next chunk		; 5
+	lda	MB_CHUNK						; 3
+	cmp	#CHUNKSIZE		; have we reached end?		; 2
+	bne	reset_chunk						; 3/2nt
+	lda	#0			; if so reset			; 2
+	sta	MB_CHUNK						; 3
+
+	; can't tail call as need to restore stack and rti
+	jsr	next_subsong		; and decompress next		; 6
+
+
+reset_chunk:
+	lda	MB_CHUNK		; reset input pointer		; 3
+	clc				; to the beginning		; 2
+
+	adc	#>UNPACK_BUFFER		; in proper chunk (1 of 3)	; 2
+	sta	INH							; 3
+
+
+								;============
+								;        18
+done_interrupt:
+	pla			; restore a				; 4
+
+	rti			; return from interrupt			; 6
+
+								;============
+								; typical
+								; 1358 cycles
+