mirror of
https://github.com/emmanuel-marty/lzsa.git
synced 2025-01-03 04:33:15 +00:00
compact decompressors for x86
This commit is contained in:
odzhan
parent
693618f100
commit
5fddaca0f8
120
asm/x86/decompress_small_v1.asm
Normal file
120
asm/x86/decompress_small_v1.asm
Normal file
@ -0,0 +1,120 @@
|
||||
; decompress_small_v1.asm - space-efficient decompressor implementation for x86
|
||||
;
|
||||
; Copyright (C) 2019 Emmanuel Marty
|
||||
;
|
||||
; This software is provided 'as-is', without any express or implied
|
||||
; warranty. In no event will the authors be held liable for any damages
|
||||
; arising from the use of this software.
|
||||
;
|
||||
; Permission is granted to anyone to use this software for any purpose,
|
||||
; including commercial applications, and to alter it and redistribute it
|
||||
; freely, subject to the following restrictions:
|
||||
;
|
||||
; 1. The origin of this software must not be misrepresented; you must not
|
||||
; claim that you wrote the original software. If you use this software
|
||||
; in a product, an acknowledgment in the product documentation would be
|
||||
; appreciated but is not required.
|
||||
; 2. Altered source versions must be plainly marked as such, and must not be
|
||||
; misrepresented as being the original software.
|
||||
; 3. This notice may not be removed or altered from any source distribution.
|
||||
|
||||
segment .text
|
||||
bits 32
|
||||
|
||||
; ---------------------------------------------------------------------------
|
||||
; Decompress raw LZSA1 block
|
||||
; inputs:
|
||||
; * esi: raw LZSA1 block
|
||||
; * edi: output buffer
|
||||
; output:
|
||||
; * eax: decompressed size
|
||||
; ---------------------------------------------------------------------------
|
||||
|
||||
%ifndef BIN
|
||||
global lzsa1_decompress
|
||||
global _lzsa1_decompress
|
||||
%endif
|
||||
|
||||
lzsa1_decompress:
|
||||
_lzsa1_decompress:
|
||||
pushad
|
||||
|
||||
;mov edi, [esp+32+4] ; edi = outbuf
|
||||
;mov esi, [esp+32+8] ; esi = inbuf
|
||||
|
||||
xor ecx, ecx
|
||||
.decode_token:
|
||||
mul ecx
|
||||
lodsb ; read token byte: O|LLL|MMMM
|
||||
mov dl, al ; keep token in dl
|
||||
|
||||
and al, 070H ; isolate literals length in token (LLL)
|
||||
shr al, 4 ; shift literals length into place
|
||||
|
||||
cmp al, 07H ; LITERALS_RUN_LEN?
|
||||
jne .got_literals ; no, we have the full literals count from the token, go copy
|
||||
|
||||
lodsb ; grab extra length byte
|
||||
add al, 07H ; add LITERALS_RUN_LEN
|
||||
jnc .got_literals ; if no overflow, we have the full literals count, go copy
|
||||
jne .mid_literals
|
||||
|
||||
lodsw ; grab 16-bit extra length
|
||||
jmp .got_literals
|
||||
|
||||
.mid_literals:
|
||||
lodsb ; grab single extra length byte
|
||||
inc ah ; add 256
|
||||
|
||||
.got_literals:
|
||||
xchg ecx, eax
|
||||
rep movsb ; copy cx literals from ds:si to es:di
|
||||
|
||||
test dl, dl ; check match offset size in token (O bit)
|
||||
js .get_long_offset
|
||||
|
||||
dec ecx
|
||||
xchg eax, ecx ; clear ah - cx is zero from the rep movsb above
|
||||
lodsb
|
||||
jmp .get_match_length
|
||||
|
||||
.get_long_offset:
|
||||
lodsw ; Get 2-byte match offset
|
||||
|
||||
.get_match_length:
|
||||
xchg eax, edx ; edx: match offset eax: original token
|
||||
and al, 0FH ; isolate match length in token (MMMM)
|
||||
add al, 3 ; add MIN_MATCH_SIZE
|
||||
|
||||
cmp al, 012H ; MATCH_RUN_LEN?
|
||||
jne .got_matchlen ; no, we have the full match length from the token, go copy
|
||||
|
||||
lodsb ; grab extra length byte
|
||||
add al,012H ; add MIN_MATCH_SIZE + MATCH_RUN_LEN
|
||||
jnc .got_matchlen ; if no overflow, we have the entire length
|
||||
jne .mid_matchlen
|
||||
|
||||
lodsw ; grab 16-bit length
|
||||
test eax, eax ; bail if we hit EOD
|
||||
je .done_decompressing
|
||||
jmp .got_matchlen
|
||||
|
||||
.mid_matchlen:
|
||||
lodsb ; grab single extra length byte
|
||||
inc ah ; add 256
|
||||
|
||||
.got_matchlen:
|
||||
xchg ecx, eax ; copy match length into ecx
|
||||
xchg esi, eax
|
||||
mov esi, edi ; esi now points at back reference in output data
|
||||
movsx edx, dx ; sign-extend dx to 32-bits.
|
||||
add esi, edx
|
||||
rep movsb ; copy match
|
||||
xchg esi, eax ; restore esi
|
||||
jmp .decode_token ; go decode another token
|
||||
|
||||
.done_decompressing:
|
||||
sub edi, [esp+32+4]
|
||||
mov [esp+28], edi ; eax = decompressed size
|
||||
popad
|
||||
ret ; done
|
||||
181
asm/x86/decompress_small_v2.asm
Normal file
181
asm/x86/decompress_small_v2.asm
Normal file
@ -0,0 +1,181 @@
|
||||
; decompress_small_v2.asm - space-efficient decompressor implementation for x86
|
||||
;
|
||||
; Copyright (C) 2019 Emmanuel Marty
|
||||
;
|
||||
; This software is provided 'as-is', without any express or implied
|
||||
; warranty. In no event will the authors be held liable for any damages
|
||||
; arising from the use of this software.
|
||||
;
|
||||
; Permission is granted to anyone to use this software for any purpose,
|
||||
; including commercial applications, and to alter it and redistribute it
|
||||
; freely, subject to the following restrictions:
|
||||
;
|
||||
; 1. The origin of this software must not be misrepresented; you must not
|
||||
; claim that you wrote the original software. If you use this software
|
||||
; in a product, an acknowledgment in the product documentation would be
|
||||
; appreciated but is not required.
|
||||
; 2. Altered source versions must be plainly marked as such, and must not be
|
||||
; misrepresented as being the original software.
|
||||
; 3. This notice may not be removed or altered from any source distribution.
|
||||
|
||||
segment .text
|
||||
bits 32
|
||||
|
||||
; ---------------------------------------------------------------------------
|
||||
; Decompress raw LZSA2 block
|
||||
; inputs:
|
||||
; * esi: raw LZSA2 block
|
||||
; * edi: output buffer
|
||||
; output:
|
||||
; * eax: decompressed size
|
||||
; ---------------------------------------------------------------------------
|
||||
|
||||
%ifndef BIN
|
||||
global lzsa2_decompress
|
||||
global _lzsa2_decompress
|
||||
%endif
|
||||
|
||||
lzsa2_decompress:
|
||||
_lzsa2_decompress:
|
||||
pushad
|
||||
|
||||
;mov edi, [esp+32+4] ; edi = outbuf
|
||||
;mov esi, [esp+32+8] ; esi = inbuf
|
||||
|
||||
xor ecx, ecx
|
||||
xor ebx, ebx ; ebx = 0100H
|
||||
inc bh
|
||||
xor ebp, ebp
|
||||
|
||||
.decode_token:
|
||||
mul ecx
|
||||
lodsb ; read token byte: XYZ|LL|MMMM
|
||||
mov dl, al ; keep token in dl
|
||||
|
||||
and al, 018H ; isolate literals length in token (LL)
|
||||
shr al, 3 ; shift literals length into place
|
||||
|
||||
cmp al, 03H ; LITERALS_RUN_LEN_V2?
|
||||
jne .got_literals ; no, we have the full literals count from the token, go copy
|
||||
|
||||
call .get_nibble ; get extra literals length nibble
|
||||
add al, cl ; add len from token to nibble
|
||||
cmp al, 012H ; LITERALS_RUN_LEN_V2 + 15 ?
|
||||
jne .got_literals ; if not, we have the full literals count, go copy
|
||||
|
||||
lodsb ; grab extra length byte
|
||||
add al,012H ; overflow?
|
||||
jnc .got_literals ; if not, we have the full literals count, go copy
|
||||
|
||||
lodsw ; grab 16-bit extra length
|
||||
|
||||
.got_literals:
|
||||
xchg ecx, eax
|
||||
rep movsb ; copy ecx literals from esi to edi
|
||||
|
||||
test dl, 0C0h ; check match offset mode in token (X bit)
|
||||
js .rep_match_or_large_offset
|
||||
|
||||
;;cmp dl,040H ; check if this is a 5 or 9-bit offset (Y bit)
|
||||
; discovered via the test with bit 6 set
|
||||
xchg ecx, eax ; clear ah - cx is zero from the rep movsb above
|
||||
jne .offset_9_bit
|
||||
|
||||
; 5 bit offset
|
||||
cmp dl, 020H ; test bit 5
|
||||
call .get_nibble_x
|
||||
jmp .dec_offset_top
|
||||
|
||||
.offset_9_bit: ; 9 bit offset
|
||||
lodsb ; get 8 bit offset from stream in A
|
||||
dec ah ; set offset bits 15-8 to 1
|
||||
test dl, 020H ; test bit Z (offset bit 8)
|
||||
je .get_match_length
|
||||
.dec_offset_top:
|
||||
dec ah ; clear bit 8 if Z bit is clear
|
||||
; or set offset bits 15-8 to 1
|
||||
jmp .get_match_length
|
||||
|
||||
.rep_match_or_large_offset:
|
||||
;;cmp dl,0c0H ; check if this is a 13-bit offset or a 16-bit offset/rep match (Y bit)
|
||||
jpe .rep_match_or_16_bit
|
||||
|
||||
; 13 bit offset
|
||||
|
||||
cmp dl, 0A0H ; test bit 5 (knowing that bit 7 is also set)
|
||||
xchg ah, al
|
||||
call .get_nibble_x
|
||||
sub al, 2 ; substract 512
|
||||
jmp .get_match_length_1
|
||||
|
||||
.rep_match_or_16_bit:
|
||||
test dl, 020H ; test bit Z (offset bit 8)
|
||||
jne .repeat_match ; rep-match
|
||||
|
||||
; 16 bit offset
|
||||
lodsb ; Get 2-byte match offset
|
||||
|
||||
.get_match_length_1:
|
||||
xchg ah, al
|
||||
lodsb ; load match offset bits 0-7
|
||||
|
||||
.get_match_length:
|
||||
xchg ebp, eax ; ebp: offset
|
||||
.repeat_match:
|
||||
xchg eax, edx ; ax: original token
|
||||
and al, 07H ; isolate match length in token (MMM)
|
||||
add al, 2 ; add MIN_MATCH_SIZE_V2
|
||||
|
||||
cmp al, 09H ; MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2?
|
||||
jne .got_matchlen ; no, we have the full match length from the token, go copy
|
||||
|
||||
call .get_nibble ; get extra literals length nibble
|
||||
add al, cl ; add len from token to nibble
|
||||
cmp al, 018H ; MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2 + 15?
|
||||
jne .got_matchlen ; no, we have the full match length from the token, go copy
|
||||
|
||||
lodsb ; grab extra length byte
|
||||
add al,018H ; overflow?
|
||||
jnc .got_matchlen ; if not, we have the entire length
|
||||
je .done_decompressing ; detect EOD code
|
||||
|
||||
lodsw ; grab 16-bit length
|
||||
|
||||
.got_matchlen:
|
||||
xchg ecx, eax ; copy match length into ecx
|
||||
xchg esi, eax
|
||||
movsx ebp, bp ; sign-extend bp to 32-bits
|
||||
lea esi,[ebp+edi] ; esi now points at back reference in output data
|
||||
rep movsb ; copy match
|
||||
xchg esi, eax ; restore esi
|
||||
jmp .decode_token ; go decode another token
|
||||
|
||||
.done_decompressing:
|
||||
sub edi, [esp+32+4]
|
||||
mov [esp+28], edi
|
||||
popad
|
||||
ret ; done
|
||||
|
||||
.get_nibble_x:
|
||||
cmc ; carry set if bit 4 was set
|
||||
rcr al, 1
|
||||
call .get_nibble ; get nibble for offset bits 0-3
|
||||
or al, cl ; merge nibble
|
||||
rol al, 1
|
||||
xor al, 0E1H ; set offset bits 7-5 to 1
|
||||
ret
|
||||
|
||||
.get_nibble:
|
||||
neg bh ; nibble ready?
|
||||
jns .has_nibble
|
||||
|
||||
xchg ebx, eax
|
||||
lodsb ; load two nibbles
|
||||
xchg ebx, eax
|
||||
|
||||
.has_nibble:
|
||||
mov cl, 4 ; swap 4 high and low bits of nibble
|
||||
ror bl, cl
|
||||
mov cl, 0FH
|
||||
and cl, bl
|
||||
ret
|
||||
Loading…
Reference in New Issue
Block a user