Apple-2-SW/dos33fsprogs
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fire: update firmware version

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This commit is contained in:
Vince Weaver 2019-01-02 21:57:40 -05:00
parent 95c6dde2e7
commit 9d08201503
1 changed files with 33 additions and 63 deletions
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96
fire/fire_firmware.s
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@ -32,15 +32,22 @@
; 109 bytes -- replace BIT/OR in low calc with an ADC
; 107 bytes -- replace self-modifying load/store absolute with Y-indirect
; 106 bytes -- assume bit 8 is as random as bit 0
; 82 bytes -- use VTAB in firmware to setup addresses
; (Antoine Vignau on comp.sys.apple2 reminded me of this)
; Zero Page
SEEDL = $4E
TEMP = $00
TEMPY = $01
OUTL = $02
OUTH = $03
INL = $04
INH = $05
OUTL = $04
OUTH = $05
BASL = $28
BASH = $29
COLOR = $30
; CRAZY OPT: start with BASL for hline in 7d0 already in place
; 100 = $64
@ -52,6 +59,16 @@ LORES = $C056 ; Enable LORES graphics
; monitor routines
GR = $F390
; VTAB notes
; if Applesoft ROM, we can jump to ASOFT_VTAB which takes value in X
; this won't work on the original Apple II with Integer ROM
; we can jum to MON.TABV instead but then have to copy the value
; to Accumulator first
; This ovewrites CV (25)
; Result is in BASL:BASH (28/29)
ASOFT_VTAB = $F25A
MON_TABV = $FB5B
fire_demo:
; GR part
@ -63,6 +80,9 @@ fire_demo:
; Setup white line on bottom
; note: calling HLINE in firmware would take at least 13 bytes
; open coded is 10
lda #$ff ; 2
ldy #39 ; 2
white_loop:
@ -82,15 +102,16 @@ yloop:
; setup the load/store addresses
; using Y-indirect is smaller than self-modifying code
jsr get_row ; 3
sty OUTL ; 2
jsr ASOFT_VTAB ; 3
lda BASL ; 2
sta OUTL ; 2
lda BASH ; 2
sta OUTH ; 2
inx ; 1
inx
jsr get_row ; 3
sty INL ; 2
sta INH ; 2
jsr ASOFT_VTAB ; 3
ldy #39 ; 2
xloop:
@ -116,14 +137,14 @@ noEor: sta SEEDL ; 2
bmi no_change ; assume bit 8 is as random as bit 0 ; 2
lda (INL),Y ; load value at row+1 ; 2
lda (BASL),Y ; load value at row+1 ; 2
and #$7 ; mask off ; 2
tax ; 1
lda <(color_progression),X ; 2
.byte $2c ; BIT trick, nops out next instruction ; 1
no_change:
lda (INL),Y ; load value at row+1 ; 2
lda (BASL),Y ; load value at row+1 ; 2
smc_sta:
@ -150,54 +171,3 @@ color_progression:
.byte $dd ; 15->13 ; 1111 1101
; Take row X and convert to address A:Y
get_row:
; get low byte
; 000X X00O
; lsr
; 0000 XX00 O
; adc #1
; 0000 XXOx
; lsr
; 0000 0XXO
; lsr
; 0000 00XX O
; ror
txa ; 1
and #$19 ; 2
lsr ; 1
adc #1 ; 2
lsr ; 1
lsr ; 1
tay ; 1
lda <low_offsets,Y ; 2
ror ; 1
tay ; 1
;===========
; 13
; high byte of store address
txa ; 1
and #$7 ; 2
lsr ; 1
ora #$4 ; 2
;===========
; 6
rts ; 1
; 14+6 = 20, as opposed to full lookup table which would be
; at least 24
; down to 13+3 at the expense of readability
; these are shifted left by one due to the algorithm
low_offsets:
.byte $00,$50,$a0