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April 26, 2025 23:31
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| ; Tim Follin's Startip 2 ported to the Commodore PET. | |
| ; The music is Follin's, the code is mine. My bits are CC0. Enjoy. | |
| ; Assemble with beebasm. | |
| org &3ff | |
| equw &401, _entry_string_end, 1 | |
| equb &9e, "1037", 0 | |
| ._entry_string_end | |
| equw 0 | |
| VIA_T1C_L = &e844 | |
| VIA_T1C_H = &e845 | |
| VIA_T1L_L = &e846 | |
| VIA_T1L_H = &e847 | |
| VIA_T2C_L = &e848 | |
| VIA_T2C_H = &e849 | |
| VIA_SR = &e84a | |
| VIA_ACR = &e84b | |
| VIA_PCR = &e84c | |
| VIA_IFR = &e84d | |
| MAX_PULSE_LEN = 16 | |
| TICKS_PER_VOL_STEP = 10 | |
| org 0 | |
| .ptr equw 0 | |
| .note_duration equw 0 | |
| .note_attack equb 0 | |
| .note_volume equb 0 | |
| .note_decay equb 0 | |
| .n1 equb 0 | |
| .n2 equb 0 | |
| .n3 equb 0 | |
| .pulse_length equb 0 | |
| .attack equb 0 | |
| .attack_flag equb 0 | |
| .duration equw 0 | |
| .etimer equb 0 | |
| .decay equb 0 | |
| org &40d | |
| ._entry | |
| sei | |
| lda #lo(music_data) | |
| sta ptr+0 | |
| lda #hi(music_data) | |
| sta ptr+1 | |
| .mainloop | |
| ldy #0 | |
| lda (ptr), y | |
| beq exit | |
| cmp #&ff | |
| bne not_envelope | |
| .envelope | |
| iny | |
| lda (ptr), y | |
| sta note_duration+0 | |
| iny | |
| lda (ptr), y | |
| sta note_duration+1 | |
| iny | |
| lda (ptr), y | |
| sta note_attack | |
| iny | |
| lda (ptr), y | |
| sta note_decay | |
| iny | |
| lda (ptr), y | |
| sta note_volume | |
| clc | |
| lda ptr+0 | |
| adc #6 | |
| sta ptr+0 | |
| lda ptr+1 | |
| adc #0 | |
| sta ptr+1 | |
| jmp mainloop | |
| .not_envelope | |
| lda note_attack | |
| sta attack | |
| lda #1 | |
| sta pulse_length | |
| sta attack_flag | |
| ldy #0 | |
| lda (ptr), y | |
| sta n1 | |
| iny | |
| lda (ptr), y | |
| sta n2 | |
| iny | |
| lda (ptr), y | |
| sta n3 | |
| lda note_duration+0 | |
| sta duration+0 | |
| lda note_duration+1 | |
| sta duration+1 | |
| lda #1 | |
| sta etimer | |
| jsr play_note | |
| clc | |
| lda ptr+0 | |
| adc #3 | |
| sta ptr+0 | |
| bcc mainloop | |
| inc ptr+1 | |
| jmp mainloop | |
| .exit | |
| cli | |
| rts | |
| macro process_note var, offset | |
| { | |
| dec var ; 5 | |
| bne exit ; 2 | |
| lda #&ec | |
| sta VIA_PCR | |
| ldx pulse_length ; 3 | |
| .loop1 | |
| dex ; 2 | |
| bne loop1 ; 2 | |
| lda #&cc ; 2 | |
| sta VIA_PCR ; 3 | |
| sec ; 2 | |
| lda #MAX_PULSE_LEN ; 2 | |
| sbc pulse_length ; 3 | |
| tax ; 2 | |
| .loop2 | |
| dex ; 2 | |
| bne loop2 ; 2 | |
| ldy #offset ; 2 | |
| lda (ptr), y ; 5 | |
| sta var ; 3 | |
| .exit | |
| } | |
| endmacro | |
| .play_note | |
| { | |
| process_note n1, 0 | |
| process_note n2, 1 | |
| process_note n3, 2 | |
| dec etimer | |
| bne not_etimer | |
| lda #TICKS_PER_VOL_STEP | |
| sta etimer | |
| lda attack_flag | |
| bne attack_flag_is_set | |
| dec decay ; 5 | |
| bne not_etimer ; 2 | |
| lda note_decay ; 3 | |
| sta decay ; 3 | |
| ldx pulse_length ; 3 | |
| dex ; 2 | |
| cpx note_volume ; 3 | |
| beq not_etimer ; 2 | |
| stx pulse_length | |
| bne not_etimer ; pulse_length is never 0 | |
| .attack_flag_is_set | |
| dec attack ; 5 | |
| bne not_etimer ; 2 | |
| lda note_attack ; 3 | |
| sta attack ; 3 | |
| ldx pulse_length ; 3 | |
| inx ; 2 | |
| stx pulse_length | |
| cpx #MAX_PULSE_LEN-1 | |
| bne not_etimer | |
| dec attack_flag | |
| dec pulse_length | |
| .not_etimer | |
| sec | |
| lda duration+0 | |
| sbc #1 | |
| sta duration+0 | |
| lda duration+1 | |
| sbc #0 | |
| sta duration+1 | |
| ora duration+0 | |
| beq exit | |
| jmp play_note | |
| .exit | |
| rts | |
| } | |
| macro envelope len, attack, decay, volume | |
| equb &ff | |
| equw len * 2/3 | |
| equb attack+1, decay+1, volume | |
| endmacro | |
| macro note a, b, c | |
| equb a/2 | |
| equb b/2 | |
| equb c/2 | |
| endmacro | |
| .music_data | |
| envelope 2400, 1, 0, 10 | |
| note &41, &52, &6d | |
| note &3d, &52, &6d | |
| note &41, &52, &6d | |
| note &49, &52, &6d | |
| envelope 38400, 0, -107, 1 | |
| note &57, &62, &83 | |
| envelope 38400, -7, -1, 15 | |
| note &57, &62, &83 | |
| envelope 2400, 3, 0, 10 | |
| note &53, &5d, &7c | |
| note &46, &5d, &7c | |
| note &3e, &5d, &7c | |
| note &46, &5d, &7c | |
| note &5d, &5d, &7c | |
| note &63, &5d, &7c | |
| note &5d, &53, &7c | |
| note &63, &53, &7c | |
| note &6e, &53, &7c | |
| note &7c, &53, &7c | |
| note &8c, &53, &7c | |
| note &7c, &53, &7c | |
| note &6f, &53, &7c | |
| note &53, &53, &7c | |
| envelope 2400, 3, 0, 10 | |
| note &64, &85, &c8 | |
| note &59, &85, &c8 | |
| note &54, &85, &c8 | |
| note &42, &84, &c7 | |
| note &54, &85, &c8 | |
| note &59, &85, &c8 | |
| note &64, &85, &c8 | |
| note &70, &86, &c8 | |
| note &4b, &96, &e1 | |
| note &54, &96, &e1 | |
| note &5f, &96, &e1 | |
| note &64, &96, &e1 | |
| note &71, &96, &e1 | |
| note &7f, &97, &e1 | |
| note &71, &96, &e1 | |
| note &64, &96, &e1 | |
| note &4e, &9d, &eb | |
| note &58, &9d, &eb | |
| note &4e, &9d, &eb | |
| note &42, &9c, &ea | |
| note &46, &9c, &eb | |
| note &58, &9c, &eb | |
| note &4e, &9d, &eb | |
| note &58, &9d, &eb | |
| note &4e, &9d, &eb | |
| note &63, &9d, &eb | |
| note &69, &9d, &eb | |
| note &84, &9d, &eb | |
| note &76, &9d, &eb | |
| note &76, &9d, &eb | |
| note &76, &9d, &eb | |
| note &76, &9d, &eb | |
| note &58, &63, &c7 | |
| note &58, &53, &c6 | |
| note &57, &41, &c5 | |
| note &57, &37, &c3 | |
| note &58, &63, &c7 | |
| note &58, &53, &c6 | |
| note &57, &41, &c5 | |
| note &57, &37, &c3 | |
| note &53, &63, &c7 | |
| note &53, &53, &c6 | |
| note &53, &41, &c5 | |
| note &53, &37, &c3 | |
| note &53, &63, &c7 | |
| note &53, &53, &c6 | |
| note &53, &41, &c5 | |
| note &53, &37, &c3 | |
| note &63, &63, &df | |
| note &63, &5e, &df | |
| note &63, &4a, &df | |
| note &63, &3e, &df | |
| note &63, &63, &df | |
| note &63, &5e, &df | |
| note &63, &4a, &df | |
| note &63, &3e, &df | |
| note &5d, &63, &df | |
| note &5d, &5e, &df | |
| note &5d, &4a, &df | |
| note &5d, &3e, &df | |
| note &5d, &63, &df | |
| note &5d, &5e, &df | |
| note &5d, &4a, &df | |
| note &5d, &3e, &df | |
| note &6f, &63, &c7 | |
| note &6f, &53, &c6 | |
| note &6f, &41, &c5 | |
| note &6f, &37, &c3 | |
| note &84, &63, &c7 | |
| note &84, &53, &c6 | |
| note &84, &41, &c5 | |
| note &84, &37, &c3 | |
| note &7d, &63, &df | |
| note &7d, &5e, &df | |
| note &7d, &4a, &df | |
| note &7d, &3e, &df | |
| note &94, &63, &df | |
| note &94, &5e, &df | |
| note &94, &4a, &df | |
| note &94, &3e, &df | |
| note &84, &63, &c7 | |
| note &84, &53, &c6 | |
| note &84, &41, &c5 | |
| note &84, &37, &c3 | |
| note &6f, &63, &c7 | |
| note &6f, &53, &c6 | |
| note &6f, &41, &c5 | |
| note &6f, &37, &c3 | |
| note &63, &63, &c7 | |
| note &63, &53, &c6 | |
| note &63, &41, &c5 | |
| note &63, &37, &c3 | |
| note &63, &63, &c7 | |
| note &63, &53, &c6 | |
| note &63, &41, &c5 | |
| note &63, &37, &c3 | |
| note &63, &63, &c7 | |
| note &5e, &53, &c6 | |
| note &63, &41, &c5 | |
| note &5e, &37, &c3 | |
| note &63, &63, &c7 | |
| note &5e, &53, &c6 | |
| note &63, &41, &c5 | |
| note &5e, &37, &c3 | |
| note &5d, &5d, &d2 | |
| note &75, &58, &d2 | |
| note &5c, &45, &cf | |
| note &58, &3a, &d0 | |
| note &5d, &5d, &d2 | |
| note &75, &58, &d2 | |
| note &5c, &45, &cf | |
| note &58, &3a, &d0 | |
| note &5d, &5d, &d2 | |
| note &75, &58, &d2 | |
| note &5c, &45, &cf | |
| note &58, &3a, &d0 | |
| note &5c, &5c, &8b | |
| note &75, &58, &8b | |
| note &5c, &45, &8b | |
| note &58, &3a, &8b | |
| note &63, &63, &de | |
| note &63, &5e, &de | |
| note &63, &4a, &dd | |
| note &62, &3e, &dc | |
| note &63, &63, &de | |
| note &63, &5e, &de | |
| note &63, &4a, &6f | |
| note &62, &3e, &dc | |
| note &63, &63, &94 | |
| note &63, &5e, &f8 | |
| note &63, &4a, &94 | |
| note &62, &3e, &f8 | |
| note &63, &63, &f8 | |
| note &63, &5e, &f8 | |
| note &63, &4a, &f8 | |
| note &62, &3e, &f8 | |
| envelope 2400, 0, 0, 13 | |
| note &63, &63, &f8 | |
| note &63, &5e, &f8 | |
| note &63, &4a, &f8 | |
| note &62, &3e, &f8 | |
| note &63, &63, &f8 | |
| note &63, &5e, &f8 | |
| note &63, &4a, &f8 | |
| note &62, &3e, &f8 | |
| note &6f, &63, &f8 | |
| note &6f, &5e, &f8 | |
| note &6f, &4a, &f8 | |
| note &6f, &3e, &f8 | |
| note &6f, &63, &f8 | |
| note &6f, &5e, &f8 | |
| note &6f, &4a, &f8 | |
| note &6f, &3e, &f8 | |
| envelope 4800, 0, 0, 13 | |
| note &4a, &59, &de | |
| note &53, &63, &dc | |
| note &59, &6f, &de | |
| note &53, &63, &dc | |
| note &63, &7c, &f9 | |
| note &58, &6f, &f9 | |
| note &4a, &58, &f9 | |
| note &58, &6f, &f9 | |
| envelope 2400, 0, 0, 13 | |
| note &57, &68, &83 | |
| note &68, &68, &83 | |
| note &83, &68, &83 | |
| note &62, &68, &83 | |
| note &68, &68, &83 | |
| note &83, &68, &83 | |
| note &62, &6f, &94 | |
| note &6f, &6f, &94 | |
| note &94, &6f, &94 | |
| note &58, &6f, &94 | |
| note &6f, &6f, &94 | |
| note &94, &6f, &94 | |
| note &57, &68, &83 | |
| note &68, &68, &83 | |
| note &83, &68, &83 | |
| note &62, &68, &83 | |
| note &68, &68, &83 | |
| note &83, &68, &83 | |
| note &62, &6f, &94 | |
| note &6f, &6f, &94 | |
| note &94, &6f, &94 | |
| note &76, &6f, &94 | |
| note &6f, &6f, &94 | |
| note &94, &6f, &94 | |
| envelope 2400, 0, 29, 1 | |
| note &6f, &94, &de | |
| note &6f, &94, &de | |
| note &6f, &94, &de | |
| note &6f, &94, &de | |
| note &7d, &a6, &de | |
| note &6f, &94, &de | |
| note &7d, &a6, &de | |
| note &6f, &94, &de | |
| note &5d, &8c, &de | |
| note &6f, &8c, &de | |
| note &6f, &8c, &de | |
| note &6f, &8c, &de | |
| note &7d, &8c, &de | |
| note &6f, &8c, &de | |
| note &5d, &8c, &de | |
| note &6f, &8c, &de | |
| note &53, &7c, &de | |
| note &63, &7c, &de | |
| note &7c, &7c, &de | |
| note &95, &7c, &de | |
| note &7c, &7c, &de | |
| note &63, &7c, &de | |
| note &53, &7c, &de | |
| note &5d, &7c, &de | |
| note &63, &7c, &de | |
| note &7c, &7c, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| note &6f, &6f, &de | |
| envelope 4800, 0, -1, 0 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| envelope 2400, 0, -1, 40 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| envelope 9600, 0, -1, 30 | |
| note &62, &7c, &a5 | |
| envelope 2400, 0, -1, 2 | |
| note &3d, &7a, &b8 | |
| note &45, &6e, &b8 | |
| note &49, &7a, &b8 | |
| note &36, &6d, &a3 | |
| note &3d, &61, &a3 | |
| note &41, &6d, &a3 | |
| note &3d, &7a, &b8 | |
| note &45, &6e, &b8 | |
| note &49, &7a, &b8 | |
| note &36, &6d, &a3 | |
| note &3d, &61, &a3 | |
| note &41, &6d, &a3 | |
| envelope 4800, 0, -1, 40 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| envelope 2400, 0, -1, 30 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| note &e0, &e1, &e2 | |
| note &5d, &7c, &93 | |
| note &e0, &e1, &e2 | |
| envelope 9600, 0, -1, 30 | |
| note &52, &6d, &82 | |
| envelope 2400, 0, -1, 2 | |
| note &3d, &7a, &b8 | |
| note &45, &6e, &b8 | |
| note &49, &7a, &b8 | |
| note &36, &6d, &a3 | |
| note &3d, &61, &a3 | |
| note &41, &6d, &a3 | |
| note &45, &8a, &cf | |
| note &4e, &7c, &cf | |
| note &53, &8b, &d0 | |
| note &3d, &7a, &b8 | |
| note &45, &6e, &b8 | |
| note &49, &7a, &b8 | |
| note &4e, &9c, &ea | |
| note &58, &8c, &ea | |
| note &5e, &9d, &eb | |
| note &45, &8a, &cf | |
| note &4e, &7c, &cf | |
| note &53, &8b, &d0 | |
| note &3d, &7a, &b8 | |
| note &45, &6e, &b8 | |
| note &49, &7a, &b8 | |
| note &36, &6d, &a3 | |
| note &3d, &61, &a3 | |
| note &41, &6d, &a3 | |
| note &30, &60, &90 | |
| note &36, &56, &90 | |
| note &39, &60, &90 | |
| note &36, &56, &90 | |
| note &30, &60, &90 | |
| note &36, &56, &90 | |
| note &39, &60, &90 | |
| note &36, &56, &90 | |
| note &30, &60, &90 | |
| note &36, &56, &90 | |
| note &39, &60, &90 | |
| note &36, &56, &90 | |
| note &30, &60, &90 | |
| note &36, &56, &90 | |
| note &39, &60, &90 | |
| note &36, &56, &90 | |
| envelope 38400, -1, -129, 1 | |
| note &39, &60, &90 | |
| equb 0 | |
| ._end | |
| SAVE "p", &3ff, _end |
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