Apple-2-SW/dos33fsprogs
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hgr: sier_hgr fix branch-always and add some more comments

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also accidentally fixes colors
This commit is contained in:
Vince Weaver 2021-04-14 10:46:14 -04:00
parent 6c3ed631fb
commit b4b5bedbf9
1 changed files with 17 additions and 19 deletions
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36
graphics/hgr/tiny_triangles/sier_hgr.s
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@ -52,7 +52,6 @@ SAVED = $FF
FULLGR = $C052
PAGE1 = $C054
PAGE2 = $C055
LORES = $C056 ; Enable LORES graphics
; ROM routines
HGR = $F3E2
@ -90,10 +89,9 @@ sier_outer:
ldx #0 ; get X 0 for later
stx YY ; YY starts at 0
; create XX_T lookup table
; note, same as YY_T lookup table?
; create XX_T and YY_T lookup tables
stx XX_TL ; start at 0
stx XX_TL ; always start at 0
stx XX_TH
; calc XX*T
@ -101,14 +99,15 @@ sier_outer:
xt_table_loop:
clc ; 2
lda XX_TL ; 3
tl_smc:
adc T_L ; 2
sta XX_TL ; 3
lda XX_TH ; 3
th_smc:
adc T_H ; 3
sta XX_TH ; 3
sta YT_LOOKUP_TABLE,X ; 5
eor #$ff ; negate, as we subtract ; 2
sta XT_LOOKUP_TABLE,X ; 5
inx ; 2
@ -128,8 +127,9 @@ no_carry:
; speed up the zoom as it goes
inc speed_smc+1
; set initial position on screen at line 32
lda #$1 ; center
lda #$0 ;
sta GBASL
lda #$42 ; start on page2 line 32 ($4200)
@ -147,7 +147,8 @@ sier_yloop:
adc #$1
sta gb_smc+1
; YY*T only needs to be updated once per line
; so do it here and then self-modify into place
ldx YY ; 3
stx add_yy_smc+1 ; 4
@ -159,7 +160,7 @@ sier_yloop:
ldx #0 ; XX
seven_loop:
ldy #7
ldy #7 ; apple ii 7 pixels per byte
sier_xloop:
@ -167,7 +168,7 @@ sier_xloop:
; SAVED = XX+(Y*T)
clc ; needed for colors ; 2
clc ; needed for proper colors ; 2
txa ; XX ; 2
yy_th_smc:
adc #$dd ; 2
@ -209,7 +210,7 @@ black:
ror ; 2
gb_smc:
sta $4000 ; 4
sta $4000 ; write to hi-res display ; 4
inc gb_smc+1 ; increase GBASL ; 6
cpx #248 ; 2
@ -218,14 +219,16 @@ gb_smc:
;=================
; total roughly ???
; 49152 per inside *80 = 3,145,728
; full screen each inner cycle is done 256*192 = 49152
; apple II cyles/frame = 17,030
; 1FPS = 1,021,800
;==================================
jsr MOVE_DOWN ; X/Y left alone
jsr MOVE_DOWN ; ROM routine to skip the next line
; as this is non-trivial on Apple II
; X/Y left alone
; returns with GBASH in A
inc YY ; repeat until YY=128
@ -234,10 +237,5 @@ gb_smc:
;flip_pages:
; TODO if frame rate ever gets fast enough
jmp sier_outer ; branch always
bmi sier_outer ; branch always
; $386, want to be at $3F5
; load at $36F???
; jmp sier