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pt3: invariant get_freq

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This commit is contained in:
Vince Weaver 2019-09-07 23:59:40 -04:00
parent b5635577a2
commit f15bab8a6c
1 changed files with 28 additions and 11 deletions
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39
interlace_demo/pt3_lib_ci.s
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@ -1994,6 +1994,9 @@ done_do_frame:
; return in freq_l/freq_h
; FIXME: self modify code
; TOTAL = 14 + 14 + 13 = 41
GetNoteFreq:
sty TEMP ; 3
@ -2001,32 +2004,45 @@ GetNoteFreq:
tay ; 2
lda PT3_LOC+PT3_HEADER_FREQUENCY ; 4
cmp #1 ; 2
bne freq_table_2 ; 2/3
bne freq_table_2 ; 3
;====
; 14
lda PT3NoteTable_ST_high,Y ; 4+
; -1
lda PT3NoteTable_ST_high,Y ; 4
sta freq_h_smc+1 ; 4
lda PT3NoteTable_ST_low,Y ; 4+
sta freq_l_smc+1 ; 4
lda PT3NoteTable_ST_low,Y ; 4
jmp freq_table_end ; 3
ldy TEMP ; 3
rts ; 6
;===========
; 40
; 14
freq_table_2:
lda PT3NoteTable_ASM_34_35_high,Y ; 4+
lda PT3NoteTable_ASM_34_35_high,Y ; 4
sta freq_h_smc+1 ; 4
lda PT3NoteTable_ASM_34_35_low,Y ; 4+
sta freq_l_smc+1 ; 4
lda PT3NoteTable_ASM_34_35_low,Y ; 4
nop ; 2
;===========
; 14
freq_table_end:
sta freq_l_smc+1 ; 4
ldy TEMP ; 3
rts ; 6
;===========
; 41
; 13
;================================================
; these must be aligned for deterministic access
; can't let a load cross a page boundary
; Table #1 of Pro Tracker 3.3x - 3.5x
; 8x12x2 bytes = 192 bytes
.align $100
PT3NoteTable_ST_high:
; 2*E, 1*D, 1*C, 2*B, 1*A, 2*9, 2*8, 3*7, 2*6, 3*5, 4*4, 5*3, 7*2, 11*1, 49*0
.byte $0E,$0E,$0D,$0C,$0B,$0B,$0A,$09
@ -2056,6 +2072,7 @@ PT3NoteTable_ST_low:
.byte $25,$23,$21,$1F,$1D,$1C,$1A,$19
.byte $17,$16,$15,$13,$12,$11,$10,$0F
.align $100
; Table #2 of Pro Tracker 3.4x - 3.5x
PT3NoteTable_ASM_34_35_high: