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638 lines
13 KiB
ArmAsm
638 lines
13 KiB
ArmAsm
;
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; Piotr Fusik, 11.11.2001
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;
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; void* inflatemem (void* dest, void* src);
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;
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.export _inflatemem
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.import popax
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.importzp sreg, ptr1, ptr2, ptr3, ptr4, tmp1, tmp2, tmp3, tmp4
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; --------------------------------------------------------------------------
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;
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; Constants
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;
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; Maximum length of a Huffman code
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MAX_BITS = 15
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; Index in bitsCount, bitsPointer_l and bitsPointer_h for literal tree
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LITERAL_TREE = 0
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; Index in bitsCount, bitsPointer_l and bitsPointer_h for distance tree
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DISTANCE_TREE = MAX_BITS
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; Size of each of bitsCount, bitsPointer_l and bitsPointer_h
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TREES_SIZE = 2*MAX_BITS+1
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; --------------------------------------------------------------------------
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;
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; Page zero
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;
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; Pointer to compressed data
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inputPointer = ptr1 ; 2 bytes
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; Pointer to uncompressed data
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outputPointer = ptr2 ; 2 bytes
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; Buffer for getBit
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getBitHold = tmp1 ; 1 byte
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; Local variables. Variables from different routines use same memory.
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cnt = tmp2 ; 1 byte
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tmp = sreg ; 1 byte
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ptr = sreg ; 2 bytes
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len = ptr3 ; 2 bytes
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nl = tmp3 ; 1 byte
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nd = tmp4 ; 1 byte
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src = ptr4 ; 2 bytes
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dest = ptr4 ; 2 bytes
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; --------------------------------------------------------------------------
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;
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; Code
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;
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_inflatemem:
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; Get inputPointer and outputPointer from stack
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jsr popax
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sta inputPointer
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stx inputPointer+1
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jsr popax
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sta outputPointer
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stx outputPointer+1
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ldy #1
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sty getBitHold
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; Get a bit of EOF and two bits of block type
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inflatemem_1:
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ldx #3
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lda #0
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jsr getBits
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lsr a
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tax
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; X contains block type, C contains EOF flag
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; Save EOF flag
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php
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; Go to the routine decompressing this block
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jsr callExtr
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plp
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bcc inflatemem_1
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lda outputPointer
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ldx outputPointer+1
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rts
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; --------------------------------------------------------------------------
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; Go to the routine decompressing block type X
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callExtr:
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lda extr_h,x
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pha
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lda extr_l,x
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pha
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rts
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; --------------------------------------------------------------------------
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; Decompress 'stored' data block
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inflateCopyBlock:
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; Ignore bits until byte boundary
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ldy #1
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sty getBitHold
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; Get 16-bit length
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ldx #inputPointer
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lda (0,x)
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sta len
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lda (inputPointer),y
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sta len+1
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; Skip length and one's compliment length
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lda #4
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clc
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adc inputPointer
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sta inputPointer
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bcc moveBlock
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inc inputPointer+1
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; fall into moveBlock
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; --------------------------------------------------------------------------
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; Copy block of length len from (0,x) to output
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moveBlock:
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ldy len
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beq moveBlock_1
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ldy #0
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inc len+1
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moveBlock_1:
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lda (0,x)
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sta (outputPointer),y
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inc 0,x
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bne moveBlock_2
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inc 1,x
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moveBlock_2:
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inc outputPointer
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bne moveBlock_3
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inc outputPointer+1
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moveBlock_3:
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dec len
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bne moveBlock_1
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dec len+1
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bne moveBlock_1
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rts
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; --------------------------------------------------------------------------
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; Decompress Huffman-coded data block with default Huffman trees:
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; literalCodeLength: 144 times 8, 112 times 9
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; endCodeLength: 24 times 7, 6 times 8
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; distanceCodeLength: 30 times 5, 2 times 8
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; (2 last codes from literal tree are not used)
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inflateFixedBlock:
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ldx #159
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stx distanceCodeLength+32
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lda #8
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inflateFixedBlock_1:
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sta literalCodeLength-1,x
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sta literalCodeLength+159-1,x
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dex
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bne inflateFixedBlock_1
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ldx #112
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lda #9
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inflateFixedBlock_2:
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sta literalCodeLength+144-1,x
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dex
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bne inflateFixedBlock_2
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ldx #24
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lda #7
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inflateFixedBlock_3:
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sta endCodeLength-1,x
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dex
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bne inflateFixedBlock_3
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ldx #30
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lda #5+DISTANCE_TREE
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inflateFixedBlock_4:
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sta distanceCodeLength-1,x
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dex
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bne inflateFixedBlock_4
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jmp inflateCodes
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; --------------------------------------------------------------------------
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; Decompress Huffman-coded data block, reading Huffman trees first
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inflateDynamicBlock:
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; numberOfLiteralCodes = getBits(5) + 257;
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ldx #5
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lda #<(lengthCodeLength-1)
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jsr getBits
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sta nl
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; numberOfDistanceCodes = getBits(5) + 1;
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ldx #5
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lda #1
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jsr getBits
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sta nd
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clc
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adc nl
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sta nl
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; numberOfTemporaryCodes = getBits(4) + 4;
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lda #4
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tax
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jsr getBits
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sta cnt
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; Clear lengths of temporary codes (there're 19 temp codes max),
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; clear literalCodeLength-1 (it may be used by temporary code 16)
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; and leave #0 in Y
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ldy #20
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lda #0
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inflateDynamicBlock_1:
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sta literalCodeLength-2,y
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dey
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bne inflateDynamicBlock_1
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; Get lengths of temporary codes in order stored in bll
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inflateDynamicBlock_2:
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ldx #3
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lda #0
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jsr getBits ; does not change Y
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ldx bll,y
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sta literalCodeLength,x
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iny
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cpy cnt
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bcc inflateDynamicBlock_2
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ror literalCodeLength+19 ; C flag is set, so it will set b7
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; Build tree for temporary codes
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jsr buildHuffmanTree
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; Use temporary codes to get lengths for literal and distance codes
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; dest is target-1, so we can access last written byte by (dest,0)
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lda #<(literalCodeLength-1)
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sta dest
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lda #>(literalCodeLength-1)
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sta dest+1
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inflateDynamicBlock_3:
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jsr fetchLiteralCode
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; Temporary code 0..15: put this length
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ldy #1
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cmp #16
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bcc inflateDynamicBlock_6
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bne inflateDynamicBlock_4
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; Temporary code 16: repeat last length 3..6 times
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ldx #2
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lda #3
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jsr getBits
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tay
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lda (dest,x) ; X == 0
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bpl inflateDynamicBlock_6 ; branch always
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inflateDynamicBlock_4:
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lsr a
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; Temporary code 17: put zero length 3..10 times
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lda #3
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tax
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bcs inflateDynamicBlock_5
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; Temporary code 18: put zero length 11..138 times
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ldx #7
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lda #11
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inflateDynamicBlock_5:
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jsr getBits
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tay
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lda #0
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; Write A length Y times
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inflateDynamicBlock_6:
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sty cnt
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inflateDynamicBlock_7:
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sta (dest),y
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dey
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bne inflateDynamicBlock_7
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lda cnt
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clc
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adc dest
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sta dest
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bcc inflateDynamicBlock_8
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inc dest+1
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inflateDynamicBlock_8:
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cmp nl
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bne inflateDynamicBlock_3
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ldy dest+1
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sbc #<endCodeLength ; C flag is set
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bcs inflateDynamicBlock_11
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dey
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inflateDynamicBlock_11:
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cpy #>endCodeLength
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bcc inflateDynamicBlock_3
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; Mark end of distance lengths
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ldx nd
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tay
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ror distanceCodeLength,x ; C flag is set, so it will set b7
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; Move distance lengths to distanceCodeLength table
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inflateDynamicBlock_9:
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dex
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lda endCodeLength,y
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; Mark existing codes (of non-zero length) as distance tree codes
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beq inflateDynamicBlock_10
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pha
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lda #0
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sta endCodeLength,y
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pla
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clc
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adc #DISTANCE_TREE
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sta distanceCodeLength,x
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inflateDynamicBlock_10:
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dey
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txa
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bne inflateDynamicBlock_9
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; fall into inflateCodes
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; --------------------------------------------------------------------------
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; Decompress data block basing on given Huffman trees
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inflateCodes:
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jsr buildHuffmanTree
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inflateCodes_1:
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jsr fetchLiteralCode
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bcc inflateCodes_2
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; Literal code
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ldy #0
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sta (outputPointer),y
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inc outputPointer
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bne inflateCodes_1
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inc outputPointer+1
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bcs inflateCodes_1 ; branch always
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; End of block
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inflateCodes_ret:
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rts
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inflateCodes_2:
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beq inflateCodes_ret
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; Repeat block
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jsr getValue
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sta len
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tya
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jsr getBits
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sta len+1
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ldx #DISTANCE_TREE
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jsr fetchCode
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jsr getValue
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sta src
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tya
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jsr getBits
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sta src+1
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lda outputPointer
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sec
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sbc src
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sta src
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lda outputPointer+1
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sbc src+1
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sta src+1
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ldx #src
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jsr moveBlock
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beq inflateCodes_1 ; branch always
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; --------------------------------------------------------------------------
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; Build Huffman trees basing on code lengths.
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; Lengths (in bits) are stored in literalCodeLength.
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; A byte with highest bit set marks end of length table.
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buildHuffmanTree:
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lda #<literalCodeLength
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sta buildHuffmanTree_3+1
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sta buildHuffmanTree_9+1
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lda #>literalCodeLength
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sta buildHuffmanTree_3+2
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sta buildHuffmanTree_9+2
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; Clear counts
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ldx #TREES_SIZE-1
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lda #0
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buildHuffmanTree_1:
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sta bitsCount,x
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dex
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bpl buildHuffmanTree_1
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bmi buildHuffmanTree_3 ; branch always
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; Count number of codes of each length
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buildHuffmanTree_2:
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inc bitsCount,x
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inc buildHuffmanTree_3+1
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bne buildHuffmanTree_3
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inc buildHuffmanTree_3+2
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buildHuffmanTree_3:
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ldx $ffff ; patched at runtime
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bpl buildHuffmanTree_2
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; Calculate pointer for each length
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tax ; ldx #0
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stx bitsCount
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lda #<sortedCodes
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ldy #>sortedCodes
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buildHuffmanTree_4:
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sta bitsPointer_l,x
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tya
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sta bitsPointer_h,x
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lda bitsCount,x
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asl a
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bcc buildHuffmanTree_5
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iny
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clc
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buildHuffmanTree_5:
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adc bitsPointer_l,x
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bcc buildHuffmanTree_6
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iny
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buildHuffmanTree_6:
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inx
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cpx #TREES_SIZE
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bcc buildHuffmanTree_4
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bcs buildHuffmanTree_9 ; branch always
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; Put codes into their place in sorted table
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buildHuffmanTree_7:
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beq buildHuffmanTree_8
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lda bitsPointer_l,x
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sta ptr
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clc
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adc #2
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sta bitsPointer_l,x
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lda bitsPointer_h,x
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sta ptr+1
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adc #0
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sta bitsPointer_h,x
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lda buildHuffmanTree_9+1
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sbc #<(endCodeLength-1) ; C flag is zero
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ldy #1
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sta (ptr),y
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lda buildHuffmanTree_9+2
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sbc #>(endCodeLength-1)
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.ifpc02
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sta (ptr)
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.else
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dey
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sta (ptr),y
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.endif
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buildHuffmanTree_8:
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inc buildHuffmanTree_9+1
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bne buildHuffmanTree_9
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inc buildHuffmanTree_9+2
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buildHuffmanTree_9:
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ldx $ffff ; patched at runtime
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bpl buildHuffmanTree_7
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rts
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; --------------------------------------------------------------------------
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; Read code basing on literal tree
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fetchLiteralCode:
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ldx #LITERAL_TREE
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; fall into fetchCode
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; --------------------------------------------------------------------------
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; Read code from input stream basing on tree given in X.
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; Return code in A, C is set if non-literal code.
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fetchCode:
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lda #0
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fetchCode_1:
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jsr getBit
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rol a
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cmp bitsCount+1,x
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bcc fetchCode_2
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sbc bitsCount+1,x
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inx
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bcs fetchCode_1 ; branch always
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fetchCode_2:
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ldy bitsPointer_l,x
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sty ptr
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ldy bitsPointer_h,x
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asl a
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bcc fetchCode_3
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iny
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fetchCode_3:
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sty ptr+1
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tay
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lda (ptr),y
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asl a
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iny
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lda (ptr),y
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rts
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; --------------------------------------------------------------------------
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; Read low byte of value (length or distance), basing on code A
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getValue:
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tay
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ldx lengthExtraBits-1,y
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lda lengthCode_l-1,y
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pha
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lda lengthCode_h-1,y
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tay
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pla
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; fall into getBits
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; --------------------------------------------------------------------------
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; Read X-bit number from input stream and adds it to A.
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; In case of carry, Y is incremented.
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; If X > 8, only 8 bits are read.
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; On return X holds number of unread bits: X = (X > 8 ? X - 8 : 0);
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getBits:
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cpx #0
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beq getBits_ret
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pha
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lda #1
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sta tmp
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pla
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getBits_1:
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jsr getBit
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bcc getBits_2
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clc
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adc tmp
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bcc getBits_2
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iny
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getBits_2:
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dex
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beq getBits_ret
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asl tmp
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bcc getBits_1
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getBits_ret:
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rts
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; --------------------------------------------------------------------------
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; Read single bit from input stream, return it in C flag
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getBit:
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lsr getBitHold
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bne getBit_ret
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pha
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.ifpc02
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lda (inputPointer)
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.else
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tya
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pha
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ldy #0
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lda (inputPointer),y
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.endif
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inc inputPointer
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bne getBit_1
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inc inputPointer+1
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getBit_1:
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ror a ; C flag set
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sta getBitHold
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.ifpc02
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.else
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pla
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tay
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.endif
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pla
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getBit_ret:
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rts
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; --------------------------------------------------------------------------
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; Addresses of functions extracting different blocks
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extr_l:
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.byte <(inflateCopyBlock-1)
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.byte <(inflateFixedBlock-1)
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.byte <(inflateDynamicBlock-1)
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extr_h:
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.byte >(inflateCopyBlock-1)
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.byte >(inflateFixedBlock-1)
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.byte >(inflateDynamicBlock-1)
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; --------------------------------------------------------------------------
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; Order, in which lengths of temporary codes are stored
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bll:
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.byte 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15
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; --------------------------------------------------------------------------
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; Tables for length and distance codes
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; Value is Code + getBits(ExtraBits)
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; Base values
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lengthCode_l:
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.byte <3,<4,<5,<6,<7,<8,<9,<10
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.byte <11,<13,<15,<17,<19,<23,<27,<31
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.byte <35,<43,<51,<59,<67,<83,<99,<115
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.byte <131,<163,<195,<227,<258
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distanceCode_l:
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.byte <1,<2,<3,<4,<5,<7,<9,<13
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.byte <17,<25,<33,<49,<65,<97,<129,<193
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.byte <257,<385,<513,<769,<1025,<1537,<2049,<3073
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.byte <4097,<6145,<8193,<12289,<16385,<24577
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lengthCode_h:
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.byte >3,>4,>5,>6,>7,>8,>9,>10
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.byte >11,>13,>15,>17,>19,>23,>27,>31
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.byte >35,>43,>51,>59,>67,>83,>99,>115
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.byte >131,>163,>195,>227,>258
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distanceCode_h:
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.byte >1,>2,>3,>4,>5,>7,>9,>13
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.byte >17,>25,>33,>49,>65,>97,>129,>193
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.byte >257,>385,>513,>769,>1025,>1537,>2049,>3073
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.byte >4097,>6145,>8193,>12289,>16385,>24577
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; Number of extra bits to read
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lengthExtraBits:
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.byte 0,0,0,0,0,0,0,0
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|
.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
|
|
|
|
; --------------------------------------------------------------------------
|
|
; Data for building literal tree
|
|
|
|
.res 1
|
|
; Length of literal codes
|
|
literalCodeLength:
|
|
.res 256
|
|
; Length of 'end' code
|
|
endCodeLength:
|
|
.res 1
|
|
; Length of 'length' codes
|
|
lengthCodeLength:
|
|
.res 29
|
|
|
|
; --------------------------------------------------------------------------
|
|
; Data for building distance tree
|
|
|
|
distanceCodeLength:
|
|
.res 30
|
|
; For two unused codes in fixed trees and an end 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
|
|
bitsPointer_h:
|
|
.res TREES_SIZE
|
|
|
|
; Sorted codes
|
|
sortedCodes:
|
|
.res 2*(256+1+29+30+2)
|
|
|
|
|
|
|