mirror of
https://github.com/cc65/cc65.git
synced 2024-12-25 17:29:50 +00:00
551 lines
15 KiB
ArmAsm
551 lines
15 KiB
ArmAsm
;
|
|
; 2017-11-07, Piotr Fusik
|
|
;
|
|
; unsigned __fastcall__ inflatemem (unsigned char* dest,
|
|
; const unsigned char* source);
|
|
;
|
|
; NOTE: Be extremely careful with modifications, because this code is heavily
|
|
; optimized for size (for example assumes certain register and flag values
|
|
; when its internal routines return). Test with the gunzip65 sample.
|
|
;
|
|
|
|
.export _inflatemem
|
|
|
|
.import incsp2
|
|
.importzp sp, sreg, ptr1, ptr2, ptr3, ptr4
|
|
|
|
; --------------------------------------------------------------------------
|
|
;
|
|
; Constants
|
|
;
|
|
|
|
; Argument values for getBits.
|
|
GET_1_BIT = $81
|
|
GET_2_BITS = $82
|
|
GET_3_BITS = $84
|
|
GET_4_BITS = $88
|
|
GET_5_BITS = $90
|
|
GET_6_BITS = $a0
|
|
GET_7_BITS = $c0
|
|
|
|
; Huffman trees.
|
|
TREE_SIZE = 16
|
|
PRIMARY_TREE = 0
|
|
DISTANCE_TREE = TREE_SIZE
|
|
|
|
; Alphabet.
|
|
LENGTH_SYMBOLS = 1+29+2 ; EOF, 29 length symbols, two unused symbols
|
|
DISTANCE_SYMBOLS = 30
|
|
CONTROL_SYMBOLS = LENGTH_SYMBOLS+DISTANCE_SYMBOLS
|
|
|
|
|
|
; --------------------------------------------------------------------------
|
|
;
|
|
; Page zero
|
|
;
|
|
|
|
; Pointer to the compressed data.
|
|
inputPointer := ptr1 ; 2 bytes
|
|
|
|
; Pointer to the uncompressed data.
|
|
outputPointer := ptr2 ; 2 bytes
|
|
|
|
; Local variables.
|
|
; As far as there is no conflict, same memory locations are used
|
|
; for different variables.
|
|
|
|
inflateStored_pageCounter := ptr3 ; 1 byte
|
|
inflateDynamic_symbol := ptr3 ; 1 byte
|
|
inflateDynamic_lastLength := ptr3+1 ; 1 byte
|
|
.assert ptr4 = ptr3 + 2, error, "Need three bytes for inflateDynamic_tempCodes"
|
|
inflateDynamic_tempCodes := ptr3+1 ; 3 bytes
|
|
inflateDynamic_allCodes := inflateDynamic_tempCodes+1 ; 1 byte
|
|
inflateDynamic_primaryCodes := inflateDynamic_tempCodes+2 ; 1 byte
|
|
inflateCodes_sourcePointer := ptr3 ; 2 bytes
|
|
inflateCodes_lengthMinus2 := ptr4 ; 1 byte
|
|
getBits_base := sreg ; 1 byte
|
|
getBit_buffer := sreg+1 ; 1 byte
|
|
|
|
|
|
; --------------------------------------------------------------------------
|
|
;
|
|
; Code
|
|
;
|
|
|
|
_inflatemem:
|
|
|
|
; inputPointer = source
|
|
sta inputPointer
|
|
stx inputPointer+1
|
|
; outputPointer = dest
|
|
ldy #1
|
|
lda (sp),y
|
|
sta outputPointer+1
|
|
dey
|
|
lda (sp),y
|
|
sta outputPointer
|
|
|
|
; ldy #0
|
|
sty getBit_buffer
|
|
|
|
inflate_blockLoop:
|
|
; Get a bit of EOF and two bits of block type
|
|
; ldy #0
|
|
sty getBits_base
|
|
lda #GET_3_BITS
|
|
jsr getBits
|
|
lsr a
|
|
; A and Z contain block type, C contains EOF flag
|
|
; Save EOF flag
|
|
php
|
|
bne inflateCompressed
|
|
|
|
; Decompress a 'stored' data block.
|
|
; ldy #0
|
|
sty getBit_buffer ; ignore bits until byte boundary
|
|
jsr getWord ; skip the length we don't need
|
|
jsr getWord ; get the one's complement length
|
|
sta inflateStored_pageCounter
|
|
bcs inflateStored_firstByte ; jmp
|
|
inflateStored_copyByte:
|
|
jsr getByte
|
|
; sec
|
|
inflateStoreByte:
|
|
jsr storeByte
|
|
bcc inflateCodes_loop
|
|
inflateStored_firstByte:
|
|
inx
|
|
bne inflateStored_copyByte
|
|
inc inflateStored_pageCounter
|
|
bne inflateStored_copyByte
|
|
|
|
; Block decompressed.
|
|
inflate_nextBlock:
|
|
plp
|
|
bcc inflate_blockLoop
|
|
|
|
; Decompression complete.
|
|
; return outputPointer - dest
|
|
lda outputPointer
|
|
; ldy #0
|
|
; sec
|
|
sbc (sp),y
|
|
iny
|
|
pha
|
|
lda outputPointer+1
|
|
sbc (sp),y
|
|
tax
|
|
pla
|
|
; pop dest
|
|
jmp incsp2
|
|
|
|
inflateCompressed:
|
|
; Decompress a Huffman-coded data block
|
|
; A=1: fixed block, initialize with fixed codes
|
|
; A=2: dynamic block, start by clearing all code lengths
|
|
; A=3: invalid compressed data, not handled in this routine
|
|
eor #2
|
|
|
|
; ldy #0
|
|
inflateCompressed_setCodeLengths:
|
|
tax
|
|
beq inflateCompressed_setLiteralCodeLength
|
|
; fixed Huffman literal codes:
|
|
; 144 8-bit codes
|
|
; 112 9-bit codes
|
|
lda #4
|
|
cpy #144
|
|
rol a
|
|
inflateCompressed_setLiteralCodeLength:
|
|
sta literalSymbolCodeLength,y
|
|
beq inflateCompressed_setControlCodeLength
|
|
; fixed Huffman control codes:
|
|
; 24 7-bit codes
|
|
; 6 8-bit codes
|
|
; 2 meaningless 8-bit codes
|
|
; 30 5-bit distance codes
|
|
lda #5+DISTANCE_TREE
|
|
cpy #LENGTH_SYMBOLS
|
|
bcs inflateCompressed_setControlCodeLength
|
|
cpy #24
|
|
adc #$100+2-DISTANCE_TREE
|
|
inflateCompressed_setControlCodeLength:
|
|
cpy #CONTROL_SYMBOLS
|
|
bcs inflateCompressed_noControlSymbol
|
|
sta controlSymbolCodeLength,y
|
|
inflateCompressed_noControlSymbol:
|
|
iny
|
|
bne inflateCompressed_setCodeLengths
|
|
|
|
tax
|
|
beq inflateDynamic
|
|
|
|
; Decompress a block
|
|
inflateCodes:
|
|
jsr buildHuffmanTree
|
|
inflateCodes_loop:
|
|
jsr fetchPrimaryCode
|
|
bcc inflateStoreByte
|
|
beq inflate_nextBlock
|
|
; Copy sequence from look-behind buffer
|
|
; ldy #0
|
|
sty getBits_base
|
|
cmp #9
|
|
bcc inflateCodes_setSequenceLength
|
|
tya
|
|
; lda #0
|
|
cpx #1+28
|
|
bcs inflateCodes_setSequenceLength
|
|
dex
|
|
txa
|
|
lsr a
|
|
ror getBits_base
|
|
inc getBits_base
|
|
lsr a
|
|
rol getBits_base
|
|
jsr getAMinus1BitsMax8
|
|
; sec
|
|
adc #0
|
|
inflateCodes_setSequenceLength:
|
|
sta inflateCodes_lengthMinus2
|
|
ldx #DISTANCE_TREE
|
|
jsr fetchCode
|
|
cmp #4
|
|
bcc inflateCodes_setOffsetLowByte
|
|
inc getBits_base
|
|
lsr a
|
|
jsr getAMinus1BitsMax8
|
|
inflateCodes_setOffsetLowByte:
|
|
eor #$ff
|
|
sta inflateCodes_sourcePointer
|
|
lda getBits_base
|
|
cpx #10
|
|
bcc inflateCodes_setOffsetHighByte
|
|
lda getNPlus1Bits_mask-10,x
|
|
jsr getBits
|
|
clc
|
|
inflateCodes_setOffsetHighByte:
|
|
eor #$ff
|
|
; clc
|
|
adc outputPointer+1
|
|
sta inflateCodes_sourcePointer+1
|
|
jsr copyByte
|
|
jsr copyByte
|
|
inflateCodes_copyByte:
|
|
jsr copyByte
|
|
dec inflateCodes_lengthMinus2
|
|
bne inflateCodes_copyByte
|
|
beq inflateCodes_loop ; jmp
|
|
|
|
inflateDynamic:
|
|
; Decompress a block reading Huffman trees first
|
|
; ldy #0
|
|
; numberOfPrimaryCodes = 257 + getBits(5)
|
|
; numberOfDistanceCodes = 1 + getBits(5)
|
|
; numberOfTemporaryCodes = 4 + getBits(4)
|
|
ldx #3
|
|
inflateDynamic_getHeader:
|
|
lda inflateDynamic_headerBits-1,x
|
|
jsr getBits
|
|
; sec
|
|
adc inflateDynamic_headerBase-1,x
|
|
sta inflateDynamic_tempCodes-1,x
|
|
dex
|
|
bne inflateDynamic_getHeader
|
|
|
|
; Get lengths of temporary codes in the order stored in inflateDynamic_tempSymbols
|
|
; ldx #0
|
|
inflateDynamic_getTempCodeLengths:
|
|
lda #GET_3_BITS
|
|
jsr getBits
|
|
ldy inflateDynamic_tempSymbols,x
|
|
sta literalSymbolCodeLength,y
|
|
ldy #0
|
|
inx
|
|
cpx inflateDynamic_tempCodes
|
|
bcc inflateDynamic_getTempCodeLengths
|
|
|
|
; Build the tree for temporary codes
|
|
jsr buildHuffmanTree
|
|
|
|
; Use temporary codes to get lengths of literal/length and distance codes
|
|
; ldx #0
|
|
; sec
|
|
inflateDynamic_decodeLength:
|
|
; C=1: literal codes
|
|
; C=0: control codes
|
|
stx inflateDynamic_symbol
|
|
php
|
|
; Fetch a temporary code
|
|
jsr fetchPrimaryCode
|
|
; Temporary code 0..15: put this length
|
|
bpl inflateDynamic_storeLengths
|
|
; 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
|
|
tax
|
|
jsr getBits
|
|
cpx #GET_3_BITS
|
|
bcc inflateDynamic_code16
|
|
beq inflateDynamic_code17
|
|
; sec
|
|
adc #7
|
|
inflateDynamic_code17:
|
|
; ldy #0
|
|
sty inflateDynamic_lastLength
|
|
inflateDynamic_code16:
|
|
tay
|
|
lda inflateDynamic_lastLength
|
|
iny
|
|
iny
|
|
inflateDynamic_storeLengths:
|
|
iny
|
|
plp
|
|
ldx inflateDynamic_symbol
|
|
inflateDynamic_storeLength:
|
|
bcc inflateDynamic_controlSymbolCodeLength
|
|
sta literalSymbolCodeLength,x
|
|
inx
|
|
cpx #1
|
|
inflateDynamic_storeNext:
|
|
dey
|
|
bne inflateDynamic_storeLength
|
|
sta inflateDynamic_lastLength
|
|
beq inflateDynamic_decodeLength ; jmp
|
|
inflateDynamic_controlSymbolCodeLength:
|
|
cpx inflateDynamic_primaryCodes
|
|
bcc inflateDynamic_storeControl
|
|
; the code lengths we skip here were zero-initialized
|
|
; in inflateCompressed_setControlCodeLength
|
|
bne inflateDynamic_noStartDistanceTree
|
|
ldx #LENGTH_SYMBOLS
|
|
inflateDynamic_noStartDistanceTree:
|
|
ora #DISTANCE_TREE
|
|
inflateDynamic_storeControl:
|
|
sta controlSymbolCodeLength,x
|
|
inx
|
|
cpx inflateDynamic_allCodes
|
|
bcc inflateDynamic_storeNext
|
|
dey
|
|
; ldy #0
|
|
jmp inflateCodes
|
|
|
|
; Build Huffman trees basing on code lengths (in bits)
|
|
; stored in the *SymbolCodeLength arrays
|
|
buildHuffmanTree:
|
|
; Clear nBitCode_literalCount, nBitCode_controlCount
|
|
tya
|
|
; lda #0
|
|
buildHuffmanTree_clear:
|
|
sta nBitCode_clearFrom,y
|
|
iny
|
|
bne buildHuffmanTree_clear
|
|
; Count number of codes of each length
|
|
; ldy #0
|
|
buildHuffmanTree_countCodeLengths:
|
|
ldx literalSymbolCodeLength,y
|
|
inc nBitCode_literalCount,x
|
|
bne buildHuffmanTree_notAllLiterals
|
|
stx allLiteralsCodeLength
|
|
buildHuffmanTree_notAllLiterals:
|
|
cpy #CONTROL_SYMBOLS
|
|
bcs buildHuffmanTree_noControlSymbol
|
|
ldx controlSymbolCodeLength,y
|
|
inc nBitCode_controlCount,x
|
|
buildHuffmanTree_noControlSymbol:
|
|
iny
|
|
bne buildHuffmanTree_countCodeLengths
|
|
; Calculate offsets of symbols sorted by code length
|
|
; lda #0
|
|
ldx #$100-4*TREE_SIZE
|
|
buildHuffmanTree_calculateOffsets:
|
|
sta nBitCode_literalOffset+4*TREE_SIZE-$100,x
|
|
clc
|
|
adc nBitCode_literalCount+4*TREE_SIZE-$100,x
|
|
inx
|
|
bne buildHuffmanTree_calculateOffsets
|
|
; Put symbols in their place in the sorted array
|
|
; ldy #0
|
|
buildHuffmanTree_assignCode:
|
|
tya
|
|
ldx literalSymbolCodeLength,y
|
|
ldy nBitCode_literalOffset,x
|
|
inc nBitCode_literalOffset,x
|
|
sta codeToLiteralSymbol,y
|
|
tay
|
|
cpy #CONTROL_SYMBOLS
|
|
bcs buildHuffmanTree_noControlSymbol2
|
|
ldx controlSymbolCodeLength,y
|
|
ldy nBitCode_controlOffset,x
|
|
inc nBitCode_controlOffset,x
|
|
sta codeToControlSymbol,y
|
|
tay
|
|
buildHuffmanTree_noControlSymbol2:
|
|
iny
|
|
bne buildHuffmanTree_assignCode
|
|
rts
|
|
|
|
; Read Huffman code using the primary tree
|
|
fetchPrimaryCode:
|
|
ldx #PRIMARY_TREE
|
|
; Read a code from input using the tree specified in X.
|
|
; Return low byte of this code in A.
|
|
; Return C flag reset for literal code, set for length code.
|
|
fetchCode:
|
|
; ldy #0
|
|
tya
|
|
fetchCode_nextBit:
|
|
jsr getBit
|
|
rol a
|
|
inx
|
|
bcs fetchCode_ge256
|
|
; are all 256 literal codes of this length?
|
|
cpx allLiteralsCodeLength
|
|
beq fetchCode_allLiterals
|
|
; is it literal code of length X?
|
|
sec
|
|
sbc nBitCode_literalCount,x
|
|
bcs fetchCode_notLiteral
|
|
; literal code
|
|
; clc
|
|
adc nBitCode_literalOffset,x
|
|
tax
|
|
lda codeToLiteralSymbol,x
|
|
fetchCode_allLiterals:
|
|
clc
|
|
rts
|
|
; code >= 256, must be control
|
|
fetchCode_ge256:
|
|
; sec
|
|
sbc nBitCode_literalCount,x
|
|
sec
|
|
; is it control code of length X?
|
|
fetchCode_notLiteral:
|
|
; sec
|
|
sbc nBitCode_controlCount,x
|
|
bcs fetchCode_nextBit
|
|
; control code
|
|
; clc
|
|
adc nBitCode_controlOffset,x
|
|
tax
|
|
lda codeToControlSymbol,x
|
|
and #$1f ; make distance symbols zero-based
|
|
tax
|
|
; sec
|
|
rts
|
|
|
|
; Read A minus 1 bits, but no more than 8
|
|
getAMinus1BitsMax8:
|
|
rol getBits_base
|
|
tax
|
|
cmp #9
|
|
bcs getByte
|
|
lda getNPlus1Bits_mask-2,x
|
|
getBits:
|
|
jsr getBits_loop
|
|
getBits_normalizeLoop:
|
|
lsr getBits_base
|
|
ror a
|
|
bcc getBits_normalizeLoop
|
|
rts
|
|
|
|
; Read 16 bits
|
|
getWord:
|
|
jsr getByte
|
|
tax
|
|
; Read 8 bits
|
|
getByte:
|
|
lda #$80
|
|
getBits_loop:
|
|
jsr getBit
|
|
ror a
|
|
bcc getBits_loop
|
|
rts
|
|
|
|
; Read one bit, return in the C flag
|
|
getBit:
|
|
lsr getBit_buffer
|
|
bne getBit_return
|
|
pha
|
|
; ldy #0
|
|
lda (inputPointer),y
|
|
inc inputPointer
|
|
bne getBit_samePage
|
|
inc inputPointer+1
|
|
getBit_samePage:
|
|
sec
|
|
ror a
|
|
sta getBit_buffer
|
|
pla
|
|
getBit_return:
|
|
rts
|
|
|
|
; Copy a previously written byte
|
|
copyByte:
|
|
ldy outputPointer
|
|
lda (inflateCodes_sourcePointer),y
|
|
ldy #0
|
|
; Write a byte
|
|
storeByte:
|
|
; ldy #0
|
|
sta (outputPointer),y
|
|
inc outputPointer
|
|
bne storeByte_return
|
|
inc outputPointer+1
|
|
inc inflateCodes_sourcePointer+1
|
|
storeByte_return:
|
|
rts
|
|
|
|
|
|
; --------------------------------------------------------------------------
|
|
;
|
|
; Constant data
|
|
;
|
|
|
|
.rodata
|
|
|
|
getNPlus1Bits_mask:
|
|
.byte GET_1_BIT,GET_2_BITS,GET_3_BITS,GET_4_BITS,GET_5_BITS,GET_6_BITS,GET_7_BITS
|
|
|
|
inflateDynamic_tempSymbols:
|
|
.byte GET_2_BITS,GET_3_BITS,GET_7_BITS,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15
|
|
|
|
inflateDynamic_headerBits:
|
|
.byte GET_4_BITS,GET_5_BITS,GET_5_BITS
|
|
inflateDynamic_headerBase:
|
|
.byte 3,LENGTH_SYMBOLS,0
|
|
|
|
|
|
; --------------------------------------------------------------------------
|
|
;
|
|
; Uninitialised data
|
|
;
|
|
|
|
.bss
|
|
|
|
; Data for building trees.
|
|
|
|
literalSymbolCodeLength:
|
|
.res 256
|
|
controlSymbolCodeLength:
|
|
.res CONTROL_SYMBOLS
|
|
|
|
; Huffman trees.
|
|
|
|
nBitCode_clearFrom:
|
|
nBitCode_literalCount:
|
|
.res 2*TREE_SIZE
|
|
nBitCode_controlCount:
|
|
.res 2*TREE_SIZE
|
|
nBitCode_literalOffset:
|
|
.res 2*TREE_SIZE
|
|
nBitCode_controlOffset:
|
|
.res 2*TREE_SIZE
|
|
allLiteralsCodeLength:
|
|
.res 1
|
|
|
|
codeToLiteralSymbol:
|
|
.res 256
|
|
codeToControlSymbol:
|
|
.res CONTROL_SYMBOLS
|