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bztsrc--bootboot/x86_64-bios/tinf.inc
2018-06-05 20:34:03 +02:00

500 lines
16 KiB
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;*
;* x86_64-bios/tinf.inc
;*
;* Copyright (C) 2017 bzt (bztsrc@gitlab)
;*
;* Permission is hereby granted, free of charge, to any person
;* obtaining a copy of this software and associated documentation
;* files (the "Software"), to deal in the Software without
;* restriction, including without limitation the rights to use, copy,
;* modify, merge, publish, distribute, sublicense, and/or sell copies
;* of the Software, and to permit persons to whom the Software is
;* furnished to do so, subject to the following conditions:
;*
;* The above copyright notice and this permission notice shall be
;* included in all copies or substantial portions of the Software.
;*
;* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
;* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
;* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
;* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
;* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
;* DEALINGS IN THE SOFTWARE.
;*
;* This file is part of the BOOTBOOT Protocol package.
;* @brief Tiny inflate, ported after tinflate.c by bzt
;*
;IN:
; esi: gzipped initrd
; edi: output buffer (guaranteed to be big enough)
; ecx: output buffer size
tinf_uncompress:
push ecx
push edi
mov edi, tinf_bss_start
mov ecx, tinf_bss_end-tinf_bss_start
xor al, al
repnz stosb
pop edi
pop ecx
mov dword [d_end], ecx
add dword [d_end], edi
.again:
; start a new block
cmp byte [d_btype], 255
jne .notst
; read final block flag
.next_blk: call tinf_getbit
mov byte [d_bfinal], al
; read block type
xor ebx, ebx
mov cl, 2
call tinf_read_bits
mov byte [d_btype], al
; build fixed huffman trees
cmp al, 1
jne @f
call tinf_build_fixed_trees
xor al, al
; decode trees from stream
@@: cmp al, 2
jne @f
call tinf_decode_trees
@@:
.notst:
; process current block
cmp byte [d_btype], 0
jnz @f
; decompress uncompressed block
call tinf_inflate_uncompressed_block
JMP .procend
@@: cmp byte [d_btype], 1
je @f
cmp byte [d_btype], 2
jne tinf_err
; decompress block with fixed/dyanamic huffman trees
; trees were decoded previously, so it's the same routine for both
@@: call tinf_inflate_block_data
.procend: cmp al, 1
jne @f
cmp byte [d_bfinal], 0
; the block has ended (without producing more data), but we
; can't return without data, so start procesing next block
jz .next_blk
ret
@@: or al, al
jnz tinf_err
cmp edi, dword [d_end]
jbe .again
ret
; build the fixed huffman trees
tinf_build_fixed_trees:
push edi
xor ecx, ecx
xor eax, eax
; build fixed length tree
mov cl, 7
mov edi, d_ltree_table
repnz stosb
mov al, 24
stosb
mov al, 152
stosb
mov al, 112
stosb
mov edi, d_ltree_trans
mov cl, 24
mov ax, 256
@@: stosw
inc ax
dec cl
jnz @b
mov cl, 144
xor ax, ax
@@: stosw
inc ax
dec cl
jnz @b
mov cl, 8
mov ax, 280
@@: stosw
inc ax
dec cl
jnz @b
mov cl, 112
mov ax, 144
@@: stosw
inc ax
dec cl
jnz @b
; build fixed distance tree
mov cl, 5
mov edi, d_dtree_table
xor al, al
repnz stosb
mov al, 32
stosb
mov edi, d_dtree_trans
mov cl, 32
xor ax, ax
@@: stosw
inc ax
dec cl
jnz @b
pop edi
ret
;IN:
; ebp: TINF_TREE
; ebx: lengths
; ecx: num
tinf_build_tree:
push edi
xor eax, eax
; clear code length count table
mov edi, ebp
stosd ; for(i=0;i<16;i++) table[i]=0;
stosd
stosd
stosd
; scan symbol lengths, and sum code length counts
push ebx
push ecx
@@: mov al, byte [ebx] ;lengths[i]
inc ebx
inc byte [ebp+eax] ;table[lengths[i]]++
dec cx
jnz @b
mov byte [ebp], 0
; compute offset table for distribution sort
mov cl, 16
xor edx, edx ;i
xor ebx, ebx ;sum
xor eax, eax
@@: mov word [offs+2*edx], bx
mov al, byte [ebp+edx]
add ebx, eax
inc edx
dec cl
jnz @b
pop ecx
pop ebx ;lengths
; create code->symbol translation table (symbols sorted by code)
xor eax, eax ;i
@@: cmp byte [ebx], 0
jz .null
xor edx, edx
mov dl, byte [ebx] ;lengths[i]
inc word [offs+2*edx]
mov dx, word [offs+2*edx]
dec dx
mov word [ebp+2*edx+16], ax
.null: inc ebx
inc eax
dec cx
jnz @b
pop edi
ret
tinf_decode_trees:
mov word [num], 0
; get 5 bits HLIT (257-286)
xor ecx, ecx
mov cl, 5
mov ebx, 257
call tinf_read_bits
mov word [hlit], ax
mov word [num], ax
; get 5 bits HDIST (1-32)
mov cl, 5
xor ebx, ebx
inc ebx
call tinf_read_bits
mov word [hdist], ax
add word [num], ax
; get 4 bits HCLEN (4-19)
mov cl, 4
mov ebx, ecx
call tinf_read_bits
mov word [hclen], ax
push edi
mov cl, 19
mov edi, lengths
xor ax, ax
repnz stosw
pop edi
; read code lengths for code length alphabet
mov edx, clcidx
; get 3 bits code length (0-7)
@@: mov cx, 3
xor ebx, ebx
call tinf_read_bits
xor ebx, ebx
mov bl, byte [edx] ;clcidx[i]
mov byte[ebx+lengths], al
inc edx
dec word [hclen]
jnz @b
; build code length tree, temporarily use length tree
mov ebp, d_ltree
mov ebx, lengths
xor ecx, ecx
mov cl, 19
call tinf_build_tree
; decode code lengths for the dynamic trees
mov edx, lengths
.decode: mov ebp, d_ltree
call tinf_decode_symbol
xor ebx, ebx
cmp al, 16
jne .not16
; copy previous code length 3-6 times (read 2 bits)
mov cl, 2
mov bl, 3
call tinf_read_bits
mov cx, ax
mov al, byte [edx-1] ;lengths[num-1]
@@: mov byte [edx], al
inc edx
dec word [num]
dec cl
jnz @b
jmp .next
.not16: cmp al, 17
jne .not17
; repeat code length 0 for 3-10 times (read 3 bits)
mov cl, 3
mov bl, cl
call tinf_read_bits
mov cx, ax
@@: mov byte [edx], 0
inc edx
dec word [num]
dec cl
jnz @b
jmp .next
.not17: cmp al, 18
jne .not18
; repeat code length 0 for 11-138 times (read 7 bits)
mov cl, 7
mov bl, 11
call tinf_read_bits
mov cx, ax
@@: mov byte [edx], 0
inc edx
dec word [num]
dec cl
jnz @b
jmp .next
.not18: ; values 0-15 represent the actual code lengths
mov byte [edx], al
inc edx
dec word [num]
.next: cmp word [num], 0
jnz .decode
; build dynamic trees
mov ebp, d_ltree
mov ebx, lengths
xor ecx, ecx
mov cx, word [hlit]
call tinf_build_tree
mov ebp, d_dtree
mov ebx, lengths
xor ecx, ecx
mov cx, word [hlit]
add ebx, ecx
mov cx, word [hdist]
call tinf_build_tree
ret
;OUT:
; al: status
tinf_inflate_block_data:
cmp word [d_curlen], 0
jne .notnull
mov ebp, d_ltree
call tinf_decode_symbol
; literal byte
cmp ax, 256
jae @f
stosb
xor al, al
ret
@@: cmp ax, 256
jne @f
; end of block
mov al, 1
ret
@@: ; substring from sliding dictionary
sub eax, 257
; possibly get more bits from length code
xor ecx, ecx
mov cl, byte [length_bits+eax]
xor ebx, ebx
mov bx, word [length_base+2*eax]
call tinf_read_bits
mov word [d_curlen], ax
; possibly get more bits from distance code
mov ebp, d_dtree
call tinf_decode_symbol
xor ecx, ecx
mov cl, byte [dist_bits+eax]
xor ebx, ebx
mov bx, word [dists_base+2*eax]
call tinf_read_bits
cmp dword [d_dict_ring], 0
neg eax
mov dword [d_lzOff], eax
.notnull: mov eax, edi
add eax, dword [d_lzOff]
mov al, byte [eax]
stosb
@@: dec word [d_curlen]
xor al, al
ret
;OUT:
; al: status
tinf_inflate_uncompressed_block:
cmp word [d_curlen], 0
jne @f
; get length
lodsw
; get one's complement of length
add esi, 2
; increment length to properly return TINF_DONE below, without
; producing data at the same time
mov word [d_curlen], ax
inc word [d_curlen]
; make sure we start next block on a byte boundary
mov byte [d_bitcount], 0
@@: dec byte [d_curlen]
cmp byte [d_curlen], 0
jnz @f
mov al, 1
ret
@@: movsb
xor al, al
ret
;OUT:
; al,zeroflag bit
tinf_getbit:
mov al, byte [d_bitcount]
or al, al
jnz @f
lodsb
mov byte [d_tag], al
mov byte [d_bitcount], 8
@@: dec byte [d_bitcount]
xor ax, ax
shr byte [d_tag], 1
adc ax, 0
ret
;IN:
; ebx: base
; cl: num
;OUT:
; eax: bits
tinf_read_bits:
push edx
or cl, cl
jz .end
xor eax, eax
xor edx, edx
inc dl
.next: call tinf_getbit
jz @f
add ebx, edx
@@: shl edx, 1
dec cl
jnz .next
.end: pop edx
mov eax, ebx
ret
;IN:
; ebp: TINF_TREE
;OUT:
; eax: trans
tinf_decode_symbol:
push edx
xor eax, eax
xor ebx, ebx ;cur
xor ecx, ecx ;len
xor edx, edx ;sum
; get more bits while code value is above sum
@@: shl ebx, 1
call tinf_getbit
add ebx, eax
inc ecx
mov al, byte [ebp+ecx]
add edx, eax
sub ebx, eax
jns @b
add edx, ebx
mov ax, word [ebp+2*edx+16]
mov ebp, edx
pop edx
ret
tinf_err:
mov esi, nogzip
jmp prot_diefunc
length_bits:
db 0, 0, 0, 0, 0, 0, 0, 0
db 1, 1, 1, 1, 2, 2, 2, 2
db 3, 3, 3, 3, 4, 4, 4, 4
db 5, 5, 5, 5, 0, 0, 0, 0
length_base:
dw 3, 4, 5, 6, 7, 8, 9, 10
dw 11, 13, 15, 17, 19, 23, 27, 31
dw 35, 43, 51, 59, 67, 83, 99, 115
dw 131, 163, 195, 227, 258, 0, 0
dist_bits:
db 0, 0, 0, 0, 1, 1, 2, 2
db 3, 3, 4, 4, 5, 5, 6, 6
db 7, 7, 8, 8, 9, 9, 10, 10
db 11, 11, 12, 12, 13, 13, 0, 0
dists_base:
dw 1, 2, 3, 4, 5, 7, 9, 13
dw 17, 25, 33, 49, 65, 97, 129, 193
dw 257, 385, 513, 769, 1025, 1537, 2049, 3073
dw 4097, 6145, 8193, 12289, 16385, 24577, 0, 0
clcidx:
db 16, 17, 18, 0, 8, 7, 9, 6
db 10, 5, 11, 4, 12, 3, 13, 2
db 14, 1, 15
d_btype: db 255