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cc65/libsrc/zlib/inflatemem.s

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;
; Piotr Fusik, 23.11.2001
;
; unsigned __fastcall__ inflatemem (char* dest, const char* source);
;
.export _inflatemem
.import incsp2
.importzp sp, sreg, ptr1, ptr2, ptr3, ptr4, tmp1
; --------------------------------------------------------------------------
;
; Constants
;
; Maximum length of a Huffman code
MAX_BITS = 15
; Index in bitsCount, bitsPointer_l and bitsPointer_h
; for temporary tree or literal/length tree
PRIMARY_TREE = 0
; Index in bitsCount, bitsPointer_l and bitsPointer_h for distance tree
DISTANCE_TREE = MAX_BITS
; Size of each of bitsCount, bitsPointer_l and bitsPointer_h
TREES_SIZE = 2*MAX_BITS
; --------------------------------------------------------------------------
;
; Page zero
;
; Pointer to compressed data
inputPointer = ptr1 ; 2 bytes
; Pointer to uncompressed data
outputPointer = ptr2 ; 2 bytes
; Local variables
getBit_hold = tmp1 ; 1 byte
inflateDynamicBlock_cnt = ptr3 ; 1 byte
inflateCodes_src = ptr3 ; 2 bytes
buildHuffmanTree_src = ptr3 ; 2 bytes
getNextLength_last = ptr3 ; 1 byte
getNextLength_index = ptr3+1 ; 1 byte
buildHuffmanTree_ptr = ptr4 ; 2 bytes
fetchCode_ptr = ptr4 ; 2 bytes
getBits_tmp = ptr4 ; 1 byte
moveBlock_len = sreg ; 2 bytes
inflateDynamicBlock_np = sreg ; 1 byte
inflateDynamicBlock_nd = sreg+1 ; 1 byte
; --------------------------------------------------------------------------
;
; Code
;
_inflatemem:
; inputPointer = source
sta inputPointer
stx inputPointer+1
; outputPointer = dest
.ifpc02
lda (sp)
ldy #1
.else
ldy #0
lda (sp),y
iny
.endif
sta outputPointer
lda (sp),y
sta outputPointer+1
; ldy #1
sty getBit_hold
inflatemem_1:
; Get a bit of EOF and two bits of block type
ldx #3
lda #0
jsr getBits
lsr a
tax
; X contains block type, C contains EOF flag
; Save EOF flag
php
; Go to the routine decompressing this block
jsr callExtr
plp
bcc inflatemem_1
; C flag is set!
; return outputPointer - dest;
lda outputPointer
.ifpc02
sbc (sp) ; C flag is set
ldy #1
.else
ldy #0
sbc (sp),y ; C flag is set
iny
.endif
pha
lda outputPointer+1
sbc (sp),y
tax
pla
; pop dest
jmp incsp2
; --------------------------------------------------------------------------
; Go to the routine decompressing block type X
callExtr:
lda extr_h,x
pha
lda extr_l,x
pha
rts
; --------------------------------------------------------------------------
; Decompress 'stored' data block
inflateCopyBlock:
; Ignore bits until byte boundary
ldy #1
sty getBit_hold
; Get 16-bit length
ldx #inputPointer
lda (0,x)
sta moveBlock_len
lda (inputPointer),y
sta moveBlock_len+1
; Skip length and one's complement of it
lda #4
clc
adc inputPointer
sta inputPointer
bcc moveBlock
inc inputPointer+1
; jmp moveBlock
; --------------------------------------------------------------------------
; Copy block of length moveBlock_len from (0,x) to output
moveBlock:
ldy moveBlock_len
beq moveBlock_1
.ifpc02
.else
ldy #0
.endif
inc moveBlock_len+1
moveBlock_1:
lda (0,x)
.ifpc02
sta (outputPointer)
.else
sta (outputPointer),y
.endif
inc 0,x
bne moveBlock_2
inc 1,x
moveBlock_2:
inc outputPointer
bne moveBlock_3
inc outputPointer+1
moveBlock_3:
.ifpc02
dey
.else
dec moveBlock_len
.endif
bne moveBlock_1
dec moveBlock_len+1
bne moveBlock_1
rts
; --------------------------------------------------------------------------
; Decompress Huffman-coded data block with default Huffman trees:
; literalCodeLength: 144 times 8, 112 times 9
; endCodeLength: 24 times 7, 6 times 8
; distanceCodeLength: 30 times 5+DISTANCE_TREE, 2 times 8
; (two 8-bit codes from primary tree are not used)
inflateFixedBlock:
ldx #159
stx distanceCodeLength+32
lda #8
inflateFixedBlock_1:
sta literalCodeLength-1,x
sta literalCodeLength+159-1,x
dex
bne inflateFixedBlock_1
ldx #112
; lda #9
inflateFixedBlock_2:
inc literalCodeLength+144-1,x ; sta
dex
bne inflateFixedBlock_2
ldx #24
; lda #7
inflateFixedBlock_3:
dec endCodeLength-1,x ; sta
dex
bne inflateFixedBlock_3
ldx #30
lda #5+DISTANCE_TREE
inflateFixedBlock_4:
sta distanceCodeLength-1,x
dex
bne inflateFixedBlock_4
jmp inflateCodes
; --------------------------------------------------------------------------
; Decompress Huffman-coded data block, reading Huffman trees first
inflateDynamicBlock:
; numberOfPrimaryCodes = 257 + getBits(5)
ldx #5
lda #1
jsr getBits
sta inflateDynamicBlock_np
; numberOfDistanceCodes = 1 + getBits(5)
ldx #5
lda #1+29+1
jsr getBits
sta inflateDynamicBlock_nd
; numberOfTemporaryCodes = 4 + getBits(4)
lda #4
tax
jsr getBits
sta inflateDynamicBlock_cnt
; Get lengths of temporary codes in order stored in tempCodeLengthOrder
ldy #0
inflateDynamicBlock_1:
ldx #3
lda #0
jsr getBits ; does not change Y
inflateDynamicBlock_2:
ldx tempCodeLengthOrder,y
sta literalCodeLength,x
iny
cpy inflateDynamicBlock_cnt
bcc inflateDynamicBlock_1
lda #0
cpy #19
bcc inflateDynamicBlock_2
ror literalCodeLength+19 ; C flag is set, so it will set b7
; Build tree for temporary codes
jsr buildHuffmanTree
; Use temporary codes to get lengths for literal/length and distance codes
ldx #0
ldy #1
stx getNextLength_last
inflateDynamicBlock_3:
jsr getNextLength
sta literalCodeLength,x
inx
bne inflateDynamicBlock_3
inflateDynamicBlock_4:
jsr getNextLength
sta endCodeLength,x
inx
cpx inflateDynamicBlock_np
bcc inflateDynamicBlock_4
.ifpc02
bcs inflateDynamicBlock_6 ; branch always
inflateDynamicBlock_5:
stz endCodeLength,x
.else
lda #0
bcs inflateDynamicBlock_6 ; branch always
inflateDynamicBlock_5:
sta endCodeLength,x
.endif
inx
inflateDynamicBlock_6:
cpx #1+29
bcc inflateDynamicBlock_5
inflateDynamicBlock_7:
jsr getNextLength
cmp #0
beq inflateDynamicBlock_8
adc #DISTANCE_TREE-1 ; C flag is set
inflateDynamicBlock_8:
sta endCodeLength,x
inx
cpx inflateDynamicBlock_nd
bcc inflateDynamicBlock_7
ror endCodeLength,x ; C flag is set, so it will set b7
; jmp inflateCodes
; --------------------------------------------------------------------------
; Decompress data block basing on given Huffman trees
inflateCodes:
jsr buildHuffmanTree
inflateCodes_1:
jsr fetchPrimaryCode
bcs inflateCodes_2
; Literal code
.ifpc02
sta (outputPointer)
.else
ldy #0
sta (outputPointer),y
.endif
inc outputPointer
bne inflateCodes_1
inc outputPointer+1
bcc inflateCodes_1 ; branch always
; End of block
inflateCodes_ret:
rts
inflateCodes_2:
beq inflateCodes_ret
; Repeat block
jsr getValue
sta moveBlock_len
tya
jsr getBits
sta moveBlock_len+1
ldx #DISTANCE_TREE
jsr fetchCode
jsr getValue
sec
eor #$ff
adc outputPointer
sta inflateCodes_src
php
tya
jsr getBits
plp
eor #$ff
adc outputPointer+1
sta inflateCodes_src+1
ldx #inflateCodes_src
jsr moveBlock
beq inflateCodes_1 ; branch always
; --------------------------------------------------------------------------
; Build Huffman trees basing on code lengths.
; Lengths (in bits) are stored in *CodeLength tables.
; A byte with highest bit set marks end of length table.
buildHuffmanTree:
lda #<literalCodeLength
sta buildHuffmanTree_src
lda #>literalCodeLength
sta buildHuffmanTree_src+1
; Clear bitsCount and bitsPointer_l
ldy #2*TREES_SIZE+1
lda #0
buildHuffmanTree_1:
sta bitsCount-1,y
dey
bne buildHuffmanTree_1
beq buildHuffmanTree_3 ; branch always
; Count number of codes of each length
buildHuffmanTree_2:
tax
inc bitsPointer_l,x
iny
bne buildHuffmanTree_3
inc buildHuffmanTree_src+1
buildHuffmanTree_3:
lda (buildHuffmanTree_src),y
bpl buildHuffmanTree_2
; Calculate pointer for each length
ldx #0
lda #<sortedCodes
ldy #>sortedCodes
clc
buildHuffmanTree_4:
sta bitsPointer_l,x
tya
sta bitsPointer_h,x
lda bitsPointer_l+1,x
adc bitsPointer_l,x ; C flag is zero
bcc buildHuffmanTree_5
iny
buildHuffmanTree_5:
inx
cpx #TREES_SIZE
bcc buildHuffmanTree_4
lda #>literalCodeLength
sta buildHuffmanTree_src+1
ldy #0
bcs buildHuffmanTree_9 ; branch always
; Put codes into their place in sorted table
buildHuffmanTree_6:
beq buildHuffmanTree_7
tax
lda bitsPointer_l-1,x
sta buildHuffmanTree_ptr
lda bitsPointer_h-1,x
sta buildHuffmanTree_ptr+1
tya
ldy bitsCount-1,x
inc bitsCount-1,x
sta (buildHuffmanTree_ptr),y
tay
buildHuffmanTree_7:
iny
bne buildHuffmanTree_9
inc buildHuffmanTree_src+1
ldx #MAX_BITS-1
buildHuffmanTree_8:
lda bitsCount,x
sta literalCount,x
dex
bpl buildHuffmanTree_8
buildHuffmanTree_9:
lda (buildHuffmanTree_src),y
bpl buildHuffmanTree_6
rts
; --------------------------------------------------------------------------
; Get next code length basing on temporary codes
getNextLength:
stx getNextLength_index
dey
bne getNextLength_1
; Fetch a temporary code
jsr fetchPrimaryCode
; Temporary code 0..15: put this length
ldy #1
cmp #16
bcc getNextLength_2
; Temporary code 16: repeat last length 3 + getBits(2) times
; Temporary code 17: put zero length 3 + getBits(3) times
; Temporary code 18: put zero length 11 + getBits(7) times
tay
ldx tempExtraBits-16,y
lda tempBaseValue-16,y
jsr getBits
cpy #17
tay
lda #0
bcs getNextLength_2
getNextLength_1:
lda getNextLength_last
getNextLength_2:
sta getNextLength_last
ldx getNextLength_index
rts
; --------------------------------------------------------------------------
; Read code basing on primary tree
fetchPrimaryCode:
ldx #PRIMARY_TREE
; jmp fetchCode
; --------------------------------------------------------------------------
; Read code from input stream basing on tree given in X.
; Return low byte of code in A.
; For literal/length tree, C is: 0 if literal code, 1 if end or length code.
fetchCode:
lda #0
fetchCode_1:
jsr getBit
rol a
cmp bitsCount,x
bcc fetchCode_2
sbc bitsCount,x ; C flag is set
inx
bcs fetchCode_1 ; branch always
fetchCode_2:
cmp literalCount,x
sta fetchCode_ptr
ldy bitsPointer_l,x
lda bitsPointer_h,x
sta fetchCode_ptr+1
lda (fetchCode_ptr),y
rts
; --------------------------------------------------------------------------
; Read low byte of value (length or distance), basing on code A
getValue:
tay
ldx lengthExtraBits-1,y
lda lengthBaseValue_l-1,y
pha
lda lengthBaseValue_h-1,y
tay
pla
; jmp getBits
; --------------------------------------------------------------------------
; Read X-bit number from input stream and add it to A.
; In case of carry, Y is incremented.
; If X > 8, only 8 bits are read.
; On return X holds number of unread bits: X = (X > 8 ? X - 8 : 0);
getBits:
cpx #0
beq getBits_ret
pha
lda #1
sta getBits_tmp
pla
getBits_1:
jsr getBit
bcc getBits_2
clc
adc getBits_tmp
bcc getBits_2
iny
getBits_2:
dex
beq getBits_ret
asl getBits_tmp
bcc getBits_1
getBits_ret:
rts
; --------------------------------------------------------------------------
; Read single bit from input stream, return it in C flag
getBit:
lsr getBit_hold
bne getBit_ret
pha
.ifpc02
lda (inputPointer)
.else
tya
pha
ldy #0
lda (inputPointer),y
.endif
inc inputPointer
bne getBit_1
inc inputPointer+1
getBit_1:
ror a ; C flag is set
sta getBit_hold
.ifpc02
.else
pla
tay
.endif
pla
getBit_ret:
rts
; --------------------------------------------------------------------------
;
; Constant data
;
.rodata
; --------------------------------------------------------------------------
; Addresses of functions extracting different blocks
extr_l:
.byte <(inflateCopyBlock-1)
.byte <(inflateFixedBlock-1)
.byte <(inflateDynamicBlock-1)
extr_h:
.byte >(inflateCopyBlock-1)
.byte >(inflateFixedBlock-1)
.byte >(inflateDynamicBlock-1)
; --------------------------------------------------------------------------
; Tables for temporary codes
; Value is BaseValue + getBits(ExtraBits)
; Order, in which lengths of temporary codes are stored
tempCodeLengthOrder:
.byte 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15
; Base values
tempBaseValue:
.byte 3,3,11
; Number of extra bits to read
tempExtraBits:
.byte 2,3,7
; --------------------------------------------------------------------------
; Tables for length and distance codes
; Value is BaseValue + getBits(ExtraBits)
; Base values
lengthBaseValue_l:
.byte <3,<4,<5,<6,<7,<8,<9,<10
.byte <11,<13,<15,<17,<19,<23,<27,<31
.byte <35,<43,<51,<59,<67,<83,<99,<115
.byte <131,<163,<195,<227,<258
distanceBaseValue_l:
.byte <1,<2,<3,<4,<5,<7,<9,<13
.byte <17,<25,<33,<49,<65,<97,<129,<193
.byte <257,<385,<513,<769,<1025,<1537,<2049,<3073
.byte <4097,<6145,<8193,<12289,<16385,<24577
lengthBaseValue_h:
.byte >3,>4,>5,>6,>7,>8,>9,>10
.byte >11,>13,>15,>17,>19,>23,>27,>31
.byte >35,>43,>51,>59,>67,>83,>99,>115
.byte >131,>163,>195,>227,>258
distanceBaseValue_h:
.byte >1,>2,>3,>4,>5,>7,>9,>13
.byte >17,>25,>33,>49,>65,>97,>129,>193
.byte >257,>385,>513,>769,>1025,>1537,>2049,>3073
.byte >4097,>6145,>8193,>12289,>16385,>24577
; Number of extra bits to read
lengthExtraBits:
.byte 0,0,0,0,0,0,0,0
.byte 1,1,1,1,2,2,2,2
.byte 3,3,3,3,4,4,4,4
.byte 5,5,5,5,0
distanceExtraBits:
.byte 0,0,0,0,1,1,2,2
.byte 3,3,4,4,5,5,6,6
.byte 7,7,8,8,9,9,10,10
.byte 11,11,12,12,13,13
; --------------------------------------------------------------------------
;
; Uninitialised data
;
.bss
; Number of literal codes of each length in primary tree
; (MAX_BITS bytes, overlap with literalCodeLength)
literalCount:
; --------------------------------------------------------------------------
; Data for building primary tree
; Lengths of literal codes
literalCodeLength:
.res 256
; Length of end code
endCodeLength:
.res 1
; Lengths of length codes
lengthCodeLength:
.res 29
; --------------------------------------------------------------------------
; Data for building distance tree
; Lengths of distance codes
distanceCodeLength:
.res 30
; For two unused codes in fixed trees and end-of-table flag
.res 3
; --------------------------------------------------------------------------
; Huffman tree structure
; Number of codes of each length
bitsCount:
.res TREES_SIZE
; Pointer to sorted codes of each length
bitsPointer_l:
.res TREES_SIZE+1
bitsPointer_h:
.res TREES_SIZE
; Sorted codes
sortedCodes:
.res 256+1+29+30+2