112 lines
3.3 KiB
ArmAsm
112 lines
3.3 KiB
ArmAsm
; this code was widely shared for playing tones on Apple II
|
|
; by POKEing the machine language and CALLing from BASIC
|
|
|
|
; it's originally by Paul Lutus, from the Apple II Red Book p45
|
|
|
|
|
|
; it's hard to find good info on this, but loading from $C030
|
|
; "toggles" the speaker. So toggling twice is esentially a square wave?
|
|
|
|
; using regular load/store/bit of $C030 is safe. Some of the more
|
|
; advanced addressing modes can double-toggle due to how some 6502
|
|
; implementations run the address bus
|
|
|
|
; these seem to have been calculated assuming a 1MHz clock
|
|
; but the Apple II actually runs at roughly 1.023MHz
|
|
|
|
; or a frequency of 1/(speaker_freq*20.46e-6)
|
|
|
|
; to go other way, speaker_freq=1/(freq*20.46e-6)
|
|
|
|
;NOTE_C3 = 376 ; 129.7 (130.8)
|
|
;NOTE_CSHARP3 = 355 ; 137.4 (138.6)
|
|
;NOTE_D3 = 335 ; 145.6 (146.8)
|
|
;NOTE_DSHARP3 = 316 ; 154.3 (155.6)
|
|
;NOTE_E3 = 298 ; 163.5 (164.8)
|
|
;NOTE_F3 = 281 ; 173.2 (174.6)
|
|
;NOTE_FSHARP3 = 265 ; 183.6 (185.0)
|
|
NOTE_G3 = 250 ; 194.5 (196.0)
|
|
NOTE_GSHARP3 = 236 ; 206.1 (207.7)
|
|
NOTE_A3 = 223 ; 218.3 (220.0)
|
|
NOTE_ASHARP3 = 210 ; 231.3 (233.1)
|
|
NOTE_B3 = 199 ; 245.0 (246.9)
|
|
NOTE_C4 = 187 ; 259.6 (261.6)
|
|
NOTE_CSHARP4 = 177 ; 275.0 (277.2)
|
|
NOTE_D4 = 167 ; 291.4 (293.7)
|
|
NOTE_DSHARP4 = 158 ; 308.6 (311.1)
|
|
NOTE_E4 = 149 ; 326.9 (329.6)
|
|
NOTE_F4 = 140 ; 346.3 (349.2)
|
|
NOTE_FSHARP4 = 132 ; 366.8 (370.0)
|
|
NOTE_G4 = 125 ; 388.5 (392.0)
|
|
NOTE_GSHARP4 = 118 ; 411.5 (415.3)
|
|
NOTE_A4 = 111 ; 435.8 (440.0)
|
|
NOTE_ASHARP4 = 105 ; 461.6 (466.2)
|
|
NOTE_B4 = 99 ; 488.9 (493.9)
|
|
NOTE_C5 = 94 ; 517.7 (523.3)
|
|
NOTE_CSHARP5 = 88 ; 548.3 (554.4)
|
|
NOTE_D5 = 83 ; 580.5 (587.3)
|
|
NOTE_DSHARP5 = 79 ; 614.8 (622.3)
|
|
NOTE_E5 = 74 ; 651.0 (659.3)
|
|
NOTE_F5 = 70 ; 689.3 (698.5)
|
|
NOTE_FSHARP5 = 66 ; 729.8 (740.0)
|
|
NOTE_G5 = 62 ; 772.6 (784.0)
|
|
NOTE_GSHARP5 = 59 ; 817.9 (830.6)
|
|
NOTE_A5 = 56 ; 865.9 (880.0)
|
|
NOTE_ASHARP5 = 52 ; 916.6 (932.3)
|
|
NOTE_B5 = 50 ; 970.3 (987.8)
|
|
NOTE_C6 = 47 ; 1027.5 (1047.0)
|
|
NOTE_CSHARP6 = 44 ; 1087.2 (1109.0)
|
|
NOTE_D6 = 42 ; 1150.7 (1175.0)
|
|
NOTE_DSHARP6 = 39 ; 1217.8 (1245.0)
|
|
NOTE_E6 = 37 ; 1288.6 (1319.0)
|
|
NOTE_F6 = 35 ; 1363.1 (1397.0)
|
|
NOTE_FSHARP6 = 33 ; 1442.1 (1480.0)
|
|
NOTE_G6 = 31 ; 1525.6 (1568.0)
|
|
NOTE_GSHARP6 = 29 ; 1613.6 (1661.0)
|
|
NOTE_A6 = 28 ; 1706.9 (1760.0)
|
|
NOTE_ASHARP6 = 26 ; 1805.6 (1865.0)
|
|
NOTE_B6 = 25 ; 1909.6 (1976.0)
|
|
|
|
|
|
;=====================================================
|
|
; speaker tone
|
|
;=====================================================
|
|
; A,X,Y trashed
|
|
; duration also trashed
|
|
|
|
; this was designed by basic to be poked into 770 ($302)
|
|
; on an Applesoft CALL, X=$9d, Y=$02 (A,Y = Address to call)
|
|
|
|
; it was originally designed for Integer BASIC where Y=0 on call
|
|
; and it was poked to $00 (zero page)
|
|
|
|
; the inner freq loop is roughly FREQ*10cycles
|
|
; so the square wave generated has a period of
|
|
; freq*20*1.023us
|
|
; or a frequency of 1/(freq*20.46e-6)
|
|
|
|
; more exactly, it is (4+10F)+(13+10F) = 20F+17
|
|
|
|
speaker_tone:
|
|
ldy #0 ; 3
|
|
speaker_tone_loop:
|
|
lda $C030 ; click speaker ; 4
|
|
speaker_loop:
|
|
dey ; ; 2
|
|
bne freq_loop ; ; 2/3
|
|
dec speaker_duration ; (Duration) ; 6
|
|
beq done_tone ; 2/3
|
|
freq_loop:
|
|
dex ; 2
|
|
bne speaker_loop ; 2/3
|
|
ldx speaker_frequency ; (Frequency) ; 4
|
|
jmp speaker_tone_loop ; 3
|
|
done_tone:
|
|
rts
|
|
|
|
speaker_duration:
|
|
.byte $00
|
|
speaker_frequency:
|
|
.byte $00
|
|
|