1
0
mirror of https://github.com/sehugg/8bitworkshop.git synced 2024-11-18 18:07:35 +00:00
8bitworkshop/presets/apple2/lz4fh.a

417 lines
12 KiB
Plaintext
Raw Normal View History

2018-08-07 20:15:45 +00:00
;
; LZ4FH uncompression for 6502
; By Andy McFadden
; Version 1.0.1, August 2015
;
; Refactored for size & speed
; by Peter Ferrie.
;
; Developed with Merlin-16
; Ported to DASM by Steven Hugg
; Apache 2.0 license
; http://www.apache.org/licenses/LICENSE-2.0
;
processor 6502
org $0803
;
; Constants
;
lz4fh_magic equ $66 ;ascii 'f'
tok_empty equ 253
tok_eod equ 254
;
; Variable storage
;
srcptr equ $3c ;2b a1l
dstptr equ $3e ;2b a1h
copyptr equ $00 ;2b
savmix equ $02 ;1b
savlen equ $03 ;1b
;
; ROM routines
;
bell equ $ff3a
monitor equ $ff69
entry
sta $c050
sta $c052
sta $c057
jsr ClrScr
jsr UnpackLZ4FH
.endless
jmp .endless
UnpackLZ4FH:
lda #<LZDATA ;copy source address to zero page
sta srcptr
lda #>LZDATA
sta srcptr+1
lda #0 ;copy destination address to zero page
sta dstptr
lda #$20
sta dstptr+1
sta _desthi+1
ldy #$00
lda (srcptr),y
cmp #lz4fh_magic ;does magic match?
beq goodmagic
fail
jsr bell
jmp monitor
; These stubs increment the high byte and then jump
; back. This saves a cycle because branch-not-taken
; becomes the common case. We assume that we're not
; unpacking data at $FFxx, so BNE is branch-always.
hi2
inc srcptr+1
bne nohi2
hi3
inc srcptr+1
clc
bcc nohi3
hi4
inc dstptr+1
bne nohi4
notempty
cmp #tok_eod
bne fail
rts ;success!
; handle "special" match values (value in A)
specialmatch
cmp #tok_empty
bne notempty
tya ;empty match, advance srcptr
adc srcptr ; past and jump to main loop
sta srcptr
bcc mainloop
inc srcptr+1
bne mainloop
hi5
inc srcptr+1
clc
bcc nohi5
goodmagic
inc srcptr
bne mainloop
inc srcptr+1
mainloop
; Get the mixed-length byte and handle the literal.
ldy #$00
lda (srcptr),y ;get mixed-length byte
sta savmix
lsr ;get the literal length
lsr
lsr
lsr
beq noliteral
cmp #$0f ;sets carry for >= 15
bne shortlit
inc srcptr
beq hi2
nohi2
lda (srcptr),y ;get length extension
adc #14 ;(carry set) add 15 - will not exceed 255
; at this point, srcptr holds the address of the "mix"
; word or the length extension, and dstptr holds the
; address of the next output location. So we want to
; read from (srcptr),y+1 and write to (dstptr),y.
; we can do this by sticking the DEY between the LDa
; and STa.
;
; We could save a couple of cycles by substituting
; addr,y in place of (dp),y, but the added setup cost
; would only benefit longer literal strings.
shortlit tax
tay
.litloop
lda (srcptr),y ;5
dey ;2 if len is 255, copy 0-254
sta (dstptr),y ;6
bne .litloop ;3 -> 16 cycles/byte
; advance srcptr by savlen+1, and dstptr by savlen
txa
sec ;this gets us the +1
adc srcptr
sta srcptr
bcs hi3
nohi3 ;carry cleared by hi3
txa
adc dstptr
sta dstptr
bcs hi4
nohi4
dey ;Y=0; DEY so next INY goes to 0
; Handle match. Y holds an offset into srcptr such
; that we need to increment it once to get the next
; interesting byte.
noliteral
lda savmix
and #$0f
cmp #$0f
bcc .shortmatch ;BCC
iny
lda (srcptr),y ;get length extension
cmp #237 ;"normal" values are 0-236
bcs specialmatch ;BCS
adc #15 ;will not exceed 255
; Put the destination address into copyptr.
.shortmatch
adc #4 ;min match; won't exceed 255
sta savlen ;save match len for later
tax ;and keep it in X
iny
lda (srcptr),y ;match offset, lo
sta copyptr
iny
lda (srcptr),y ;match offset, hi
_desthi ora #$00 ;OR in hi-res page
sta copyptr+1
; advance srcptr past the encoded match while we still
; remember how many bytes it took to encode. Y is
; indexing the last value used, so we want to go
; advance srcptr by Y+1.
tya
sec
adc srcptr
sta srcptr
bcs hi5
nohi5 ;hi5 clears carry
; Copy the match. The length is in X. Note this
; must be a forward copy so overlapped data works.
;
; We know the match is at least 4 bytes long, so
; we could save a few cycles by not doing the
; aDC #4 earlier, and unrolling the first 4
; load/store operations here.
ldy #$00
.copyloop
lda (copyptr),y ;5
sta (dstptr),y ;6
iny ;2
dex ;2
bne .copyloop ;3 -> 18 cycles/byte
; advance dstptr past copied data
lda dstptr
adc savlen ;carry is clear
sta dstptr
bcc mainloop
inc dstptr+1
bne mainloop ;always (not unpacking at $FFxx)
ClrScr:
lda #$20
sta .clrloop+2
ldy #0
lda #0
.clrloop sta $2000,y
iny
bne .clrloop
inc .clrloop+2
ldx .clrloop+2
cpx #$40
bne .clrloop
rts
LZDATA:
2018-08-07 20:15:45 +00:00
; WORLDMAP file
hex 661f7f1400002001002900b040014019
hex 0000007c000008290041030600032a00
hex 43065433002900980000403f00002603
hex 0059005102000000202a000668000249
hex 002f0100128100134080001536770011
hex 042900213c6429001a0f9f006760004b
hex 0000025900536000000008e2002f3066
hex 27740025043c5900170ca30083106040
hex 1370472102a5005a1000000018810014
hex 0357014f0600071c2674005844780300
hex 007800140ce0004510000004a3005a20
hex 781f0030810014017f003f0818000e73
hex 00430c003010350137700106a2000958
hex 00576003044003f201420a607c0fa600
hex 121e290017059d000a2c020875001030
hex 6e0134000e075900617c7f01007c0157
hex 011306590010222c005a0e0c20030c9a
hex 002270063d021220400192030c000440
hex 01000660d90008ad021b30d8010f0176
hex 00f2031e18400100400700067f1f6a38
hex 0c4001000f630150387e00002c0c034a
hex 39005000810022700f3f0014014a005f
hex 604001000c017e004f330000600ceb02
hex 2400042c026230005c1b00422802162c
hex 49002d1f0380001403bc0113082a021f
hex 401580000f2178005001006000403800
hex 133e5601223e029b02477805541fa100
hex 6f7e03007e0702425a002a3200b10021
hex 204428001a079f007a30004e00000208
hex 6d0204ea002f1c22267400260e06ad02
hex 04ea000141016830003f647c204c013a
hex 1000005a00190885030f1077002d7001
hex 9c0029047cdc0104c404762038007031
hex 0006cb012c0e30570523016080002f78
hex 0f0ef20153381800781fb50037304003
hex a20019092e024702040001f201750e40
hex 1738004001c3002770079d002f400105
hex 6902581f0000637109027702407b7f07
hex 0010c304aa3360034001023860000e9a
hex 00130f210212234001210206cd021a02
hex d8000440050a9b000f01770012707f00
hex a37c71004f2008400040014803401e00
hex 00070c031d332c034630060006c20412
hex 404c001f08017e001f3e0ee802340660
hex 07a700621800761e004e7b0016244900
hex 5c0703011800d90124003cc2032f4001
hex 4ccc0311402c04210c03c40012303606
hex 22000cec052a7400a10038380f0a5900
hex 110691030348030f2973001c13b00424
hex 7c01b500431e704301a6007a10004c01
hex 0000049d00130c6b001f0627f3043a0a
hex 030c300513303f057f10006e07002006
hex 094d05140cb3001f021373004d401f7f
hex 019d051a0cb303250001330535730f03
hex a3006a6003600018009b001f3017e903
hex 537830037801350136607101a2002a40
hex 0d59001706df006200001c0033604e00
hex 0288022850015c060f06e80267010060
hex 3f5f038103857f466a7d0d001000d800
hex ba4013205e4101037840010e81002518
hex 3c9e0200e3022f420307cd061f1810e8
hex 0634400107df00523078410070d10060
hex 40471f0000034f001d132c0346600700
hex 0cd60212604c004f180040011fd60373
hex 40073000400118c20343460300789a07
hex 151e4a005a0e420108039b0045030000
hex 68c2071f004fcc074240134004750002
hex 72080367054a481b0700a10038000e08
hex 590014045501000c030f2973002a1100
hex b100246001b40044701b1066cd083a18
hex 0000d80805d70c4f4000000227f30436
hex 3b010cb30a02d10804e10a5766050020
hex 044d011c3059051f04186a097f607f7f
hex 417f00400b9c09044c0902e700451e78
hex 0160cc095a00400008006b021f1007e9
hex 021c1c2e0b4460030e0f350d205b0310
hex 0603ce090aad06560606600300c00242
hex 140020204e0002580018589c091f6009
hex 680a45010f037c58006966434f3a6d39
hex 970a8c19307e4001014000ac0a227020
hex 49001223e100226300cd020f01d3061f
hex 0c11e80324410fdf0280103c41001c00
hex 7e016900137f4b004c200f6071810012
hex 04980b2418783a096f40010010004020
hex d50382600c1f0000077c1f900723043a
hex c30235016c1f4a00241e42ef0508b503
hex 234007d10c1f604dcb0b00e805101653
hex 0a1570240a0367013a685101a0002c38
hex 3006020336001340640e0f2477003a40
hex 1104b1002238033401644003100c1027
hex cd084d0f000003b0071f062feb0c1725
hex ac0a17303a0d5a300840630f4a0d1c20
hex 5905140633010f107205933f00784118
hex 007041038e071403a6051a005b10255e
hex 013301560c40006001a5105f070c0040
hex 0114dc0d2a76012e0200390a14073501
hex 01ad06102e2d004a03003c0e310f3704
hex 700f3f0e303c0020a50605bd0c186cdb
hex 001f2006e8021107290d2506065f0786
hex 0f583f0f60007000d800321f103ea70e
hex 2a1c009a0018273e0a40003f00001703
hex 1f0400d3062f300410e8032438479c02
hex 901c1c644101060003011e06133a4b00
hex 4e300b30012e0f01a70033704f0f5101
hex 0027132f006020d50382266c0100002f
hex 3c70d10823042e590026314821065d3c
hex 5e007818b00723000c3a091f204dcb0b
hex 1178470e560320000400c80311100f06
hex 2a7300a0002a6e388100150867104f01
hex 0040702774003a601807b100237c0145
hex 066306101c506101ce0900e7100acf03
hex 23010071091f0129f1083567010b5900
hex 17203a0d8f607f1f0378066006094d11
hex 1302ea012f40010e7300406001004e22
hex 0f137f58002f4c0701a6115638007833
hex 01b3004640072001a5002a0404fe0a2f
hex 001c06e902393803073103775e61637e
hex 037f01d702aa403b0040016002600700
hex 0702370c071f3f0e31680020d7143260
hex 677daa000759001f2007e70201210270
hex 6a037c07001c003d1292180e106c0c40
hex 036001520e70601f00007c300ea70e4a
hex 030138008100192c71024f7301000804
hex cf123f600c0e0fe903246c44db04e37e
hex 040c000102004101001860033e4b003d
hex 700a1880004506000003340d13184803
hex 2f38301fd503307c3f361006023c0242
hex 10000c66290036033f0c210a5e287000
hex 7870b0131338c0020f4eca1300571430
hex 3440011b0f069902121c9f120a9f003a
hex 404f28a911181867141f582774003a20
hex 7801b1001236380364037e0c187070cc
hex 1116306d1106780023600362012f0432
hex 2674003946410ddd00240018b5066710
hex 0040074003cd180f0758150f0ff20121
hex 7c0332182340738b02147da515190631
hex 0323000ce805022b1636072003a50058
hex 3c0700000f5c021f0605690220406f2e
hex 0d163d3403517347637f01c504160836
hex 0379400130062003007800471848055c
hex bf0231580130cd0231387c4728001812
hex 5b161f100b6816f3040e00000c703f00
hex 1c780770030630587c030660cd08613c
hex 700300602fa6124a4701280081003728
hex 7003a300511e01000841d0121d039700
hex 1f0810e803244747c600606f7c180001
hex 03210f440e70011c4703131fa0170a5b
hex 002406003a0d130c6c0c2f6f1f1fd503
hex 1106591a232006650804701948062c64
hex 0122142a60438000140167001f6050c8
hex 1313002c1808b3002f783f0241182a40
hex 69d602173067102f604c2774003a3c28
hex 00b1001203400177406319184021034d
hex 013a080002db011530610d1f1627f418
hex 2a61069e001708e00d07ca010e551114
hex 032c022f08700ff201430403601fd10c
hex 64707f03007818a5001a02ae19053c02
hex 1103c20023201ea5005906000078012b
hex 0a3f4000020569022060063801263f03
hex 5e0146076307011b1200510410018b0b
hex 490420070c7800577058044006c00221
hex 0118cd02410c70010306030f135b1a14
hex 040c0ad0130e0007007c1c7e7f215e3b
hex 0e3c0612786c01500e407f793ca70e3d
hex 6d00780406277e017c0032010078cf1a
hex 0d80000030001f300d6b031406ac0662
hex 6039403c0003a81d157849003f401706
hex 012d1b1504340d1f0628cc0331030013
hex c21821000cbc0c130c711536047c6621
hex 0a005a062c0343b1031a006a000f1500
hex 000ffe