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pt3: combine $d0/$e0 decode

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This commit is contained in:
Vince Weaver 2019-06-05 11:19:09 -04:00
parent 8691e095f4
commit f3fe83bfc4
1 changed files with 16 additions and 24 deletions
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40
pt3_player/pt3_lib.s
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@ -16,6 +16,7 @@
; + 2937 bytes -- qkumba first pass
; + 2879 bytes -- qkumba second pass
; + 2839 bytes -- mask note command in common code
; + 2832 bytes -- combine $D0 and $E0 decode
; TODO
; move some of these flags to be bits rather than bytes?
@ -1311,7 +1312,7 @@ decode_case_cX:
;==============================
; $CX -- set volume
;==============================
cmp #$c0 ; 2
cmp #$c0 ; check top nibble $C ; 2
bne decode_case_dX ; 3
; -1
lda note_command_bottom ; 4
@ -1334,42 +1335,33 @@ decode_case_dX:
;==============================
; $DX/$EX -- change sample
;==============================
; D0 = special case (end note)
; D1-EF = set sample to (value - $D0)
; if $D0
cmp #$d0 ; 2
bne decode_case_dX_eX ; 3
cmp #$f0 ; check top nibble $D/$E ; 2
beq decode_case_fX ; 3
; -1
; only gets here if $D0??
lda note_command ; 4
sec ; 2
sbc #$d0 ; 3
beq decode_case_d0
lda note_command_bottom ; 4
bne decode_case_dx_not_d0 ; 3
decode_case_not_d0:
jsr load_sample ; load sample in bottom nybble ; 6+??
bcc done_decode ; branch always ; 3
;========================
; d0 case means end note
decode_case_d0:
rol decode_done ; deep magic ; 6
; where is C set?
bne done_decode ; branch always ; 3
decode_case_dX_eX:
cmp #$e0 ; 2
bne decode_case_fX
lda note_command
sec
sbc #$d0
;fall through
decode_case_dx_not_d0:
jsr load_sample ; load sample in bottom nybble
bcc done_decode ; branch always
;==============================
; $FX - change ornament/sample
;==============================