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dos33fsprogs
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fire_tiny: load in zero page

This commit is contained in:
Vince Weaver 2018-12-30 02:26:08 -05:00
parent cfb81b0ec6
commit c8e0be4dab
3 changed files with 63 additions and 94 deletions
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4
fire/Makefile
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@ -9,7 +9,7 @@ all: fire.dsk
fire.dsk: FIRE FIRE_TINY HELLO fire.dsk: FIRE FIRE_TINY HELLO
$(DOS33) -y fire.dsk SAVE A HELLO $(DOS33) -y fire.dsk SAVE A HELLO
$(DOS33) -y fire.dsk BSAVE -a 0x1000 FIRE $(DOS33) -y fire.dsk BSAVE -a 0x1000 FIRE
$(DOS33) -y fire.dsk BSAVE -a 0x1000 FIRE_TINY $(DOS33) -y fire.dsk BSAVE -a 0x70 FIRE_TINY
#### ####
@ -23,7 +23,7 @@ fire.o: fire.s gr_fast_clear.s vapor_lock.s \
#### ####
FIRE_TINY: fire_tiny.o FIRE_TINY: fire_tiny.o
ld65 -o FIRE_TINY fire_tiny.o -C ../linker_scripts/apple2_1000.inc ld65 -o FIRE_TINY fire_tiny.o -C ../linker_scripts/apple2_70.inc
fire_tiny.o: fire_tiny.s fire_tiny.o: fire_tiny.s
ca65 -o fire_tiny.o fire_tiny.s -l fire_tiny.lst ca65 -o fire_tiny.o fire_tiny.s -l fire_tiny.lst

141
fire/fire_tiny.s
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@ -5,43 +5,51 @@
; based on code described here http://fabiensanglard.net/doom_fire_psx/ ; based on code described here http://fabiensanglard.net/doom_fire_psx/
; 611 bytes at first ; 611 bytes at first
; 601 bytes -- strip out some unused code6 ; 601 bytes -- strip out some unused code
; 592 bytes -- don't init screen ; 592 bytes -- don't init screen
; 443 bytes -- remove more dead code ; 443 bytes -- remove more dead code
; 206 bytes -- no need to clear screen ; 206 bytes -- no need to clear screen
; 193 bytes -- un-cycle exact the random16 code ; 193 bytes -- un-cycle exact the random16 code
; 189 bytes -- more optimization of random16 code
; 161 bytes -- move to 8-bit RNG
; 152 bytes -- reduce lookup to top half colors (had to remove brown)
; also changed maroon to pink
; 149 bytes -- use monitor GR
; Zero Page ; Zero Page
SEEDL = $4E SEEDL = $4E
SEEDH = $4F TEMP = $00
TEMP = $FA TEMPY = $01
TEMPY = $FB
XOR_MAGIC = $7657 ; "vW" ; 100 = $64
; Soft Switches ; Soft Switches
SET_GR = $C050 ; Enable graphics SET_GR = $C050 ; Enable graphics
FULLGR = $C052 ; Full screen, no text FULLGR = $C052 ; Full screen, no text
LORES = $C056 ; Enable LORES graphics LORES = $C056 ; Enable LORES graphics
; monitor routines
GR = $F390
fire_demo: fire_demo:
; GR part ; GR part
bit LORES ; 4 jsr GR ; 3
bit SET_GR ; 4 bit FULLGR ; 3
bit FULLGR ; 4 ;==========
; 6
; Setup white line on bottom ; Setup white line on bottom
lda #$ff lda #$ff ; 2
ldx #39 ldx #39 ; 2
white_loop: white_loop:
sta $7d0,X ; hline 24 (46+47) sta $7d0,X ; hline 24 (46+47) ; 3
dex dex ; 1
bpl white_loop bpl white_loop ; 2
;============
; 10
fire_loop: fire_loop:
@ -65,11 +73,27 @@ xloop:
smc1: smc1:
lda $7d0,X lda $7d0,X
sta TEMP sta TEMP
and #$f ; mask off and #$7 ; mask off
tay tay
jsr random16 ;=============================
; random8
;=============================
; 8-bit 6502 Random Number Generator
; Linear feedback shift register PRNG by White Flame
; http://codebase64.org/doku.php?id=base:small_fast_8-bit_prng
random8:
lda SEEDL lda SEEDL
beq doEor
asl
beq noEor ; if the input was $80, skip the EOR
bcc noEor
doEor: eor #$1d
noEor: sta SEEDL
; end inlined RNG
and #$1 and #$1
beq no_change beq no_change
@ -91,88 +115,21 @@ smc2:
dey dey
bpl yloop bpl yloop
bmi fire_loop
jmp fire_loop
color_progression: color_progression:
.byte 0 ; 0->0 .byte $00 ; 8->0 ; 1000 0101
.byte $88 ; 1->8 .byte $bb ; 9->11 ; 1001 0001
.byte 0 ; 2->0 .byte 0 ; 10->0 ; 1010 0000
.byte 0 ; 3->0 .byte $aa ; 11->10 ; 1011 0000
.byte 0 ; 4->0 .byte 0 ; 12->0 ; 1100 0000
.byte 0 ; 5->0 .byte $99 ; 13->9 ; 1101 1001
.byte 0 ; 6->0 .byte $00 ; 14->0 ; 1110 0000
.byte 0 ; 7->0 .byte $dd ; 15->13 ; 1111 1101
.byte $55 ; 8->5
.byte $11 ; 9->1
.byte 0 ; 10->0
.byte 0 ; 11->0
.byte 0 ; 12->0
.byte $99 ; 13->9
.byte 0 ; 14->0
.byte $dd ; 15->13
; 16-bit 6502 Random Number Generator
; Linear feedback shift register PRNG by White Flame
; http://codebase64.org/doku.php?id=base:small_fast_16-bit_prng
;=============================
; random16
;=============================
random16:
lda SEEDL ; 3
beq low_zero ; $0000 and $8000 are special values ; 3
;==========
; 6
lownz:
; -1
asl SEEDL ; Do a normal shift ; 5
lda SEEDH ; 3
rol ; 2
bcs do_eor ; 3
bcc no_eor ; 3
do_eor:
; high byte is in A
eor #>XOR_MAGIC ; 2
sta SEEDH ; 3
lda SEEDL ; 3
eor #<XOR_MAGIC ; 2
sta SEEDL ; 3
eor_rts:
rts ; 6
no_eor:
sta SEEDH ; 3
jmp eor_rts ; 3+6
;===========
; 20
low_zero:
lda SEEDH ; 3
beq do_eor ; High byte is also zero ; 3
; so apply the EOR
ceo: ; -1
; wasn't zero, check for $8000
asl ; 2
beq no_eor ; if $00 is left after the shift; 3
; then it was $80
; else, do the EOR based on the carry
cep:
bcc no_eor
bcs do_eor
gr_offsets: gr_offsets:
.word $400,$480,$500,$580,$600,$680,$700,$780 .word $400,$480,$500,$580,$600,$680,$700,$780
.word $428,$4a8,$528,$5a8,$628,$6a8,$728,$7a8 .word $428,$4a8,$528,$5a8,$628,$6a8,$728,$7a8
.word $450,$4d0,$550,$5d0,$650,$6d0,$750,$7d0 .word $450,$4d0,$550,$5d0,$650,$6d0,$750,$7d0

12
linker_scripts/apple2_70.inc Normal file
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@ -0,0 +1,12 @@
MEMORY {
ZP: start = $00, size = $1A, type = rw;
RAM: start = $70, size = $8E00, file = %O;
}
SEGMENTS {
CODE: load = RAM, type = ro;
RODATA: load = RAM, type = ro;
DATA: load = RAM, type = rw;
BSS: load = RAM, type = bss, define = yes;
ZEROPAGE: load = ZP, type = zp;
}