dos33fsprogs/tfv/duet.s
2017-05-03 00:40:33 -04:00

173 lines
5.2 KiB
ArmAsm

; ***************************************************************************
; * Copyright (C) 1979-2015 by Paul Lutus *
; * http://arachnoid.com/administration *
; * *
; * This program is free software; you can redistribute it and/or modify *
; * it under the terms of the GNU General Public License as published by *
; * the Free Software Foundation; either version 2 of the License, or *
; * (at your option) any later version. *
; * *
; * This program is distributed in the hope that it will be useful, *
; * but WITHOUT ANY WARRANTY; without even the implied warranty of *
; * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
; * GNU General Public License for more details. *
; * *
; * You should have received a copy of the GNU General Public License *
; * along with this program; if not, write to the *
; * Free Software Foundation, Inc., *
; * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
; ***************************************************************************
; Electric Duet Player Routine circa 1980
.define EQU =
; These are all "Free" zero page locations
LOC6 EQU $06
LOC7 EQU $07
DURATION EQU $08
LOC9 EQU $09
LOC1D EQU $1D
MADDRL EQU $1E
MADDRH EQU $1F
LOC4E EQU $4E
LOC4F EQU $4F
play_ed:
LDA #$01 ; 900: A9 01 ; 2 *!*
STA LOC9 ; 902: 85 09 ; 3
STA LOC1D ; 904: 85 1D ; 3
PHA ; 906: 48 ; 3
PHA ; 907: 48 ; 3
PHA ; 908: 48 ; 3
BNE label1 ; 909: D0 15 ; 4 *!*
label2:
INY ; 90B: C8 ; 2
LDA (MADDRL),Y ; 90C: B1 1E ; 5 *!*
STA LOC9 ; 90E: 85 09 ; 3
INY ; 910: C8 ; 2
LDA (MADDRL),Y ; 911: B1 1E ; 5 *!*
STA LOC1D ; 913: 85 1D ; 3
loop:
LDA MADDRL ; 915: A5 1E ; 3 *!*
CLC ; 917: 18 ; 2
ADC #$03 ; 918: 69 03 ; 2 *!*
STA MADDRL ; 91A: 85 1E ; 3
BCC label1 ; 91C: 90 02 ; 4 *!*
INC MADDRH ; 91E: E6 1F ; 5
label1:
LDY #$00 ; 920: A0 00 ; 2 *!* Set Y to zero
LDA (MADDRL),Y ; 922: B1 1E ; 5 *!* Load first byte
CMP #$01 ; 924: C9 01 ; 2 Compare to 1
BEQ label2 ; 926: F0 E3 ; 4 *!* If one ?
BCS play_note ; 928: B0 0D ; 4 *!* If >1, then duration
PLA ; 92A: 68 ; 4 POP
PLA ; 92B: 68 ; 4 POP
PLA ; 92C: 68 ; 4 POP
sub1:
LDX #$49 ; 92D: A2 49 ; 2 *!* X=0x49 (EOR opcode)
INY ; 92F: C8 ; 2 increment to next byte
LDA (MADDRL),Y ; 930: B1 1E ; 5 *!* load next byte
BNE label4 ; 932: D0 02 ; 4 *!* if not zero
LDX #$C9 ; 934: A2 C9 ; 2 *!* X=0xC9 (CMP opcode)
label4:
RTS ; 936: 60 ; 6 return
play_note:
STA DURATION ; 937: 85 08 ; 3
JSR sub1 ; 939: 20 2D09 ; 6
STX $0983 ; 93C: 8E 8309 ; 4 self-modify EOR/CMP
STA LOC6 ; 93F: 85 06 ; 3
LDX LOC9 ; 941: A6 09 ; 3 *!*
label5:
LSR A ; 943: 4A ; 2
DEX ; 944: CA ; 2
BNE label5 ; 945: D0 FC ; 4 *!*
STA $097C ; 947: 8D 7C09 ; 4 ; self-modify
JSR sub1 ; 94A: 20 2D09 ; 6
STX $09BB ; 94D: 8E BB09 ; 4 ; self-modify
STA LOC7 ; 950: 85 07 ; 3
LDX LOC1D ; 952: A6 1D ; 3 *!*
label6:
LSR A ; 954: 4A ; 2
DEX ; 955: CA ; 2
BNE label6 ; 956: D0 FC ; 4 *!*
STA $09B4 ; 958: 8D B409 ; 4 ; self-modify
PLA ; 95B: 68 ; 4
TAY ; 95C: A8 ; 2
PLA ; 95D: 68 ; 4
TAX ; 95E: AA ; 2
PLA ; 95F: 68 ; 4
BNE label8 ; 960: D0 03 ; 4 *!*
label99:
BIT $C030 ; 962: 2C 30C0 ; 4 SPEAKER
label8:
CMP #$00 ; 965: C9 00 ; 2
BMI label7 ; 967: 30 03 ; 4 *!*
NOP ; 969: EA ; 2
BPL label9 ; 96A: 10 03 ; 4 *!*
label7:
BIT $C030 ; 96C: 2C 30C0 ; 4 SPEAKER
label9:
STA LOC4E ; 96F: 85 4E ; 3
BIT $C000 ; 971: 2C 00C0 ; 4
BMI label4 ; 974: 30 C0 ; 4 *!*
DEY ; 976: 88 ; 2
BNE label10 ; 977: D0 02 ; 4 *!*
BEQ label11 ; 979: F0 06 ; 4 *!*
label10:
CPY #$00 ; 97B: C0 00 ; 2
BEQ label12 ; 97D: F0 04 ; 4 *!* !!!
BNE label13 ; 97F: D0 04 ; 4 *!*
label11:
LDY LOC6 ; 981: A4 06 ; 3 *!*
label12:
EOR #$40 ; 983: 49 40 ; 2 *!* !!!
label13:
BIT LOC4E ; 985: 24 4E ; 3
BVC label14 ; 987: 50 07 ; 4 *!*
BVS label15 ; 989: 70 00 ; 4 *!*
label15:
BPL label16 ; 98B: 10 09 ; 4 *!*
NOP ; 98D: EA ; 2
BMI label17 ; 98E: 30 09 ; 4 *!*
label14:
NOP ; 990: EA ; 2
BMI label16 ; 991: 30 03 ; 4 *!*
NOP ; 993: EA ; 2
BPL label17 ; 994: 10 03 ; 4 *!*
label16:
CMP $C030 ; 996: CD 30C0 ; 4 SPEAKER
label17:
DEC LOC4F ; 999: C6 4F ; 5
BNE label18 ; 99B: D0 11 ; 4 *!*
DEC DURATION ; 99D: C6 08 ; 5
BNE label18 ; 99F: D0 0D ; 4 *!*
BVC label19 ; 9A1: 50 03 ; 4 *!*
BIT $C030 ; 9A3: 2C 30C0 ; 4 SPEAKER
label19:
PHA ; 9A6: 48 ; 3
TXA ; 9A7: 8A ; 2
PHA ; 9A8: 48 ; 3
TYA ; 9A9: 98 ; 2
PHA ; 9AA: 48 ; 3
JMP loop ; 9AB: 4C 1509 ; 3
label18:
DEX ; 9AE: CA ; 2
BNE label20 ; 9AF: D0 02 ; 4 *!*
BEQ label21 ; 9B1: F0 06 ; 4 *!*
label20:
CPX #$00 ; 9B3: E0 00 ; 2
BEQ label22 ; 9B5: F0 04 ; 4 *!* !!!
BNE label23 ; 9B7: D0 04 ; 4 *!*
label21:
LDX LOC7 ; 9B9: A6 07 ; 3 *!*
label22:
EOR #$80 ; 9BB: 49 80 ; 2 *!* !!!
label23:
BVS label99 ; 9BD: 70 A3 ; 4 *!*
NOP ; 9BF: EA ; 2
BVC label8 ; 9C0: 50 A3 ; 4 *!*