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pt3: more decoding

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This commit is contained in:
Vince Weaver 2019-05-11 00:11:53 -04:00
parent dedb2137b9
commit 2348e249d9
1 changed files with 39 additions and 14 deletions
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53
pt3_player/pt3_lib.s
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@ -342,25 +342,42 @@ no_accum:
; }
; }
;====================
; set amplitude
lda sample_b1 ; a->amplitude= (b1 & 0xf);
and #$f
sta note_a+NOTE_AMPLITUDE
; adjust amplitude sliding
; if ((b0 & 0x80)!=0) {
; if ((b0&0x40)!=0) {
; if (a->amplitude_sliding < 15) {
; a->amplitude_sliding++;
; }
; }
; else {
; if (a->amplitude_sliding > -15) {
; a->amplitude_sliding--;
; }
; }
; }
lda sample_b0 ; if ((b0 & 0x80)!=0) {
and #$80
beq done_amp_sliding
; a->amplitude+=a->amplitude_sliding;
lda sample_b0 ; if ((b0&0x40)!=0) {
and #$40
beq amp_slide_down
amp_slide_up:
lda note_a+NOTE_AMPLITUDE_SLIDING
cmp #15
bcs done_amp_sliding ; bge
; if (a->amplitude_sliding < 15) {
inc note_a+NOTE_AMPLITUDE_SLIDING ; a->amplitude_sliding++;
jmp done_amp_sliding
amp_slide_down:
lda note_a+NOTE_AMPLITUDE_SLIDING
cmp #$f2 ; -14 1111 0010
bcc done_amp_sliding ; if (a->amplitude_sliding > -15) {
dec note_a+NOTE_AMPLITUDE_SLIDING ; ; a->amplitude_sliding--;
done_amp_sliding:
; a->amplitude+=a->amplitude_sliding;
clc
lda note_a+NOTE_AMPLITUDE
adc note_a+NOTE_AMPLITUDE_SLIDING
sta note_a+NOTE_AMPLITUDE
; clamp amplitude to 0 - 15
@ -429,7 +446,15 @@ freq_slide:
; }
; }
; pt3->mixer_value = ((b1 >>1) & 0x48) | pt3->mixer_value;
;======================
; set mixer
lda sample_b1 ; pt3->mixer_value = ((b1 >>1) & 0x48) | pt3->mixer_value;
lsr
and #$48
ora pt3_mixer_value
sta pt3_mixer_value
; a->sample_position++;
; if (a->sample_position >= a->sample_length) {