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674 lines
14 KiB
ArmAsm
674 lines
14 KiB
ArmAsm
;
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; Piotr Fusik, 21.09.2003
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;
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; unsigned __fastcall__ inflatemem (char* dest, const char* source);
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;
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.export _inflatemem
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.import incsp2
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.importzp sp, sreg, ptr1, ptr2, ptr3, ptr4, tmp1
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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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; All Huffman trees are stored in the bitsCount, bitsPointer_l
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; and bitsPointer_h arrays. There may be two trees: the literal/length tree
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; and the distance tree, or just one - the temporary tree.
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; Index in the mentioned arrays for the beginning of the literal/length tree
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; or the temporary tree.
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PRIMARY_TREE = 0
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; Index in the mentioned arrays for the beginning of the distance tree.
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DISTANCE_TREE = MAX_BITS
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; Size of each array.
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TREES_SIZE = 2*MAX_BITS
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; --------------------------------------------------------------------------
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;
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; Page zero
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;
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; Pointer to the compressed data.
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inputPointer = ptr1 ; 2 bytes
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; Pointer to the uncompressed data.
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outputPointer = ptr2 ; 2 bytes
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; Local variables.
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; As far as there is no conflict, same memory locations are used
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; for different variables.
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inflateDynamicBlock_cnt = ptr3 ; 1 byte
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inflateCodes_src = ptr3 ; 2 bytes
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buildHuffmanTree_src = ptr3 ; 2 bytes
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getNextLength_last = ptr3 ; 1 byte
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getNextLength_index = ptr3+1 ; 1 byte
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buildHuffmanTree_ptr = ptr4 ; 2 bytes
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fetchCode_ptr = ptr4 ; 2 bytes
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getBits_tmp = ptr4 ; 1 byte
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moveBlock_len = sreg ; 2 bytes
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inflateDynamicBlock_np = sreg ; 1 byte
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inflateDynamicBlock_nd = sreg+1 ; 1 byte
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getBit_hold = tmp1 ; 1 byte
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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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; inputPointer = source
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sta inputPointer
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stx inputPointer+1
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; outputPointer = dest
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.ifpc02
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lda (sp)
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ldy #1
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.else
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ldy #0
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lda (sp),y
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iny
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.endif
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sta outputPointer
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lda (sp),y
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sta outputPointer+1
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; ldy #1
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sty getBit_hold
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inflatemem_1:
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; Get a bit of EOF and two bits of block type
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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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; A and Z contain 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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; C flag is set!
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; return outputPointer - dest;
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lda outputPointer
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.ifpc02
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sbc (sp) ; C flag is set
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ldy #1
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.else
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ldy #0
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sbc (sp),y ; C flag is set
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iny
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.endif
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pha
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lda outputPointer+1
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sbc (sp),y
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tax
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pla
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; pop dest
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jmp incsp2
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; --------------------------------------------------------------------------
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; Go to proper block decoding routine.
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callExtr:
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bne inflateCompressedBlock
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; --------------------------------------------------------------------------
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; Decompress a '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 getBit_hold
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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 moveBlock_len
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lda (inputPointer),y
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sta moveBlock_len+1
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; Skip the length and one's complement of it
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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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; jmp moveBlock
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; --------------------------------------------------------------------------
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; Copy block of length moveBlock_len from (0,x) to the output.
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moveBlock:
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ldy moveBlock_len
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beq moveBlock_1
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.ifpc02
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.else
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ldy #0
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.endif
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inc moveBlock_len+1
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moveBlock_1:
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lda (0,x)
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.ifpc02
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sta (outputPointer)
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.else
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sta (outputPointer),y
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.endif
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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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.ifpc02
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dey
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.else
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dec moveBlock_len
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.endif
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bne moveBlock_1
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dec moveBlock_len+1
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bne moveBlock_1
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rts
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; --------------------------------------------------------------------------
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; Decompress a Huffman-coded data block
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; (A = 1: fixed, A = 2: dynamic).
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inflateCompressedBlock:
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lsr a
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bne inflateDynamicBlock
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; Note: inflateDynamicBlock may assume that A = 1
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; --------------------------------------------------------------------------
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; Decompress a Huffman-coded data block with default Huffman trees
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; (defined by the DEFLATE format):
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; literalCodeLength: 144 times 8, 112 times 9
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; endCodeLength: 7
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; lengthCodeLength: 23 times 7, 6 times 8
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; distanceCodeLength: 30 times 5+DISTANCE_TREE, 2 times 8
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; (two 8-bit codes from the primary 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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inc literalCodeLength+144-1,x ; sta
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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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dec endCodeLength-1,x ; sta
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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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beq inflateCodes ; branch always
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; --------------------------------------------------------------------------
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; Decompress a Huffman-coded data block, reading Huffman trees first.
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inflateDynamicBlock:
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; numberOfPrimaryCodes = 257 + getBits(5)
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ldx #5
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; lda #1
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jsr getBits
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sta inflateDynamicBlock_np
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; numberOfDistanceCodes = 1 + getBits(5)
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ldx #5
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lda #1+29+1
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jsr getBits
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sta inflateDynamicBlock_nd
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; numberOfTemporaryCodes = 4 + getBits(4)
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lda #4
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tax
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jsr getBits
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sta inflateDynamicBlock_cnt
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; Get lengths of temporary codes in the order stored in tempCodeLengthOrder
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txa ; lda #0
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tay
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inflateDynamicBlock_1:
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ldx #3 ; A = 0
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jsr getBits ; does not change Y
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inflateDynamicBlock_2:
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ldx tempCodeLengthOrder,y
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sta literalCodeLength,x
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lda #0
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iny
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cpy inflateDynamicBlock_cnt
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bcc inflateDynamicBlock_1
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cpy #19
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bcc inflateDynamicBlock_2
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ror literalCodeLength+19 ; C flag is set, so this will set b7
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; Build the tree for temporary codes
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jsr buildHuffmanTree
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; Use temporary codes to get lengths of literal/length and distance codes
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ldx #0
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ldy #1
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stx getNextLength_last
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inflateDynamicBlock_3:
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jsr getNextLength
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sta literalCodeLength,x
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inx
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bne inflateDynamicBlock_3
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inflateDynamicBlock_4:
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jsr getNextLength
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inflateDynamicBlock_5:
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sta endCodeLength,x
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inx
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cpx inflateDynamicBlock_np
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bcc inflateDynamicBlock_4
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lda #0
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cpx #1+29
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bcc inflateDynamicBlock_5
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inflateDynamicBlock_6:
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jsr getNextLength
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cmp #0
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beq inflateDynamicBlock_7
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adc #DISTANCE_TREE-1 ; C flag is set
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inflateDynamicBlock_7:
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sta endCodeLength,x
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inx
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cpx inflateDynamicBlock_nd
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bcc inflateDynamicBlock_6
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ror endCodeLength,x ; C flag is set, so this will set b7
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; jmp inflateCodes
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; --------------------------------------------------------------------------
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; Decompress a 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 fetchPrimaryCode
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bcs inflateCodes_2
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; Literal code
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.ifpc02
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sta (outputPointer)
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.else
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ldy #0
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sta (outputPointer),y
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.endif
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inc outputPointer
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bne inflateCodes_1
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inc outputPointer+1
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bcc 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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; Restore a block from the look-behind buffer
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jsr getValue
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sta moveBlock_len
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tya
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jsr getBits
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sta moveBlock_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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sec
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eor #$ff
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adc outputPointer
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sta inflateCodes_src
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php
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tya
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jsr getBits
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plp
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eor #$ff
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adc outputPointer+1
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sta inflateCodes_src+1
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ldx #inflateCodes_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 (in bits).
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; stored in the *CodeLength arrays.
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; A byte with its highest bit set marks the end.
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buildHuffmanTree:
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lda #<literalCodeLength
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sta buildHuffmanTree_src
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lda #>literalCodeLength
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sta buildHuffmanTree_src+1
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; Clear bitsCount and bitsPointer_l
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ldy #2*TREES_SIZE+1
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lda #0
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buildHuffmanTree_1:
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sta bitsCount-1,y
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dey
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bne buildHuffmanTree_1
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beq 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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tax
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inc bitsPointer_l,x
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iny
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bne buildHuffmanTree_3
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inc buildHuffmanTree_src+1
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buildHuffmanTree_3:
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lda (buildHuffmanTree_src),y
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bpl buildHuffmanTree_2
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; Calculate a pointer for each length
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ldx #0
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lda #<sortedCodes
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ldy #>sortedCodes
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clc
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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 bitsPointer_l+1,x
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adc bitsPointer_l,x ; C flag is zero
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bcc buildHuffmanTree_5
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iny
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buildHuffmanTree_5:
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inx
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cpx #TREES_SIZE
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bcc buildHuffmanTree_4
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lda #>literalCodeLength
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sta buildHuffmanTree_src+1
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ldy #0
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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_6:
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beq buildHuffmanTree_7
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tax
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lda bitsPointer_l-1,x
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sta buildHuffmanTree_ptr
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lda bitsPointer_h-1,x
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sta buildHuffmanTree_ptr+1
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tya
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ldy bitsCount-1,x
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inc bitsCount-1,x
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sta (buildHuffmanTree_ptr),y
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tay
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buildHuffmanTree_7:
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iny
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bne buildHuffmanTree_9
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inc buildHuffmanTree_src+1
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ldx #MAX_BITS-1
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buildHuffmanTree_8:
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lda bitsCount,x
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sta literalCount,x
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dex
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bpl buildHuffmanTree_8
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buildHuffmanTree_9:
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lda (buildHuffmanTree_src),y
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bpl buildHuffmanTree_6
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rts
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; --------------------------------------------------------------------------
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; Decode next code length using temporary codes.
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getNextLength:
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stx getNextLength_index
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dey
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bne getNextLength_1
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; Fetch a temporary code
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jsr fetchPrimaryCode
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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 getNextLength_2
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; Temporary code 16: repeat last length 3 + getBits(2) times
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; Temporary code 17: put zero length 3 + getBits(3) times
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; Temporary code 18: put zero length 11 + getBits(7) times
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tay
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ldx tempExtraBits-16,y
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lda tempBaseValue-16,y
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jsr getBits
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cpy #17
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tay
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txa ; lda #0
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bcs getNextLength_2
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getNextLength_1:
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lda getNextLength_last
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getNextLength_2:
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sta getNextLength_last
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ldx getNextLength_index
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rts
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; --------------------------------------------------------------------------
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; Read a code basing on the primary tree.
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fetchPrimaryCode:
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ldx #PRIMARY_TREE
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; jmp fetchCode
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; --------------------------------------------------------------------------
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; Read a code from input basing on the tree specified in X.
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; Return low byte of this code in A.
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; For the literal/length tree, the C flag is set if the code is non-literal.
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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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inx
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sec
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sbc bitsCount-1,x
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bcs fetchCode_1
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adc bitsCount-1,x ; C flag is zero
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cmp literalCount-1,x
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sta fetchCode_ptr
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ldy bitsPointer_l-1,x
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lda bitsPointer_h-1,x
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sta fetchCode_ptr+1
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lda (fetchCode_ptr),y
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rts
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; --------------------------------------------------------------------------
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; Decode low byte of a value (length or distance), basing on the code in A.
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; The result is the base value for this code plus some bits read from input.
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getValue:
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tay
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ldx lengthExtraBits-1,y
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lda lengthBaseValue_l-1,y
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pha
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lda lengthBaseValue_h-1,y
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tay
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pla
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; jmp getBits
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; --------------------------------------------------------------------------
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; Read X-bit number from the input and add it to A.
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; Increment Y if overflow.
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; If X > 8, read only 8 bits.
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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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.ifpc02
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stz getBits_tmp
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dec getBits_tmp
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.else
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pha
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lda #$ff
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sta getBits_tmp
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pla
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.endif
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getBits_1:
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jsr getBit
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bcc getBits_2
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sbc getBits_tmp ; C flag is set
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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 getBits_tmp
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bmi getBits_1
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getBits_ret:
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rts
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; --------------------------------------------------------------------------
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; Read a single bit from input, return it in the C flag.
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getBit:
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lsr getBit_hold
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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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sty getBit_hold
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ldy #0
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lda (inputPointer),y
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ldy getBit_hold
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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 is set
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sta getBit_hold
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pla
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getBit_ret:
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rts
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; --------------------------------------------------------------------------
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;
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; Constant data
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;
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.rodata
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; --------------------------------------------------------------------------
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; Arrays for the temporary codes.
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; Order, in which lengths of the temporary codes are stored.
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tempCodeLengthOrder:
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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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; Base values.
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tempBaseValue:
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.byte 3,3,11
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; Number of extra bits to read.
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tempExtraBits:
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.byte 2,3,7
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; --------------------------------------------------------------------------
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; Arrays for the length and distance codes.
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; Base values.
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lengthBaseValue_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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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 the primary tree
|
|
; (MAX_BITS bytes, overlap with literalCodeLength).
|
|
literalCount:
|
|
|
|
; --------------------------------------------------------------------------
|
|
; Data for building the primary tree.
|
|
|
|
; Lengths of literal codes.
|
|
literalCodeLength:
|
|
.res 256
|
|
; Length of the end code.
|
|
endCodeLength:
|
|
.res 1
|
|
; Lengths of length codes.
|
|
lengthCodeLength:
|
|
.res 29
|
|
|
|
; --------------------------------------------------------------------------
|
|
; Data for building the distance tree.
|
|
|
|
; Lengths of distance codes.
|
|
distanceCodeLength:
|
|
.res 30
|
|
; For two unused codes in the fixed trees and an 'end' mark.
|
|
.res 3
|
|
|
|
; --------------------------------------------------------------------------
|
|
; The Huffman trees.
|
|
|
|
; Number of codes of each length.
|
|
bitsCount:
|
|
.res TREES_SIZE
|
|
; Pointers 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
|
|
|
|
|
|
|