mirror of
https://github.com/emmanuel-marty/lzsa.git
synced 2025-04-06 20:37:12 +00:00
Emmanuel Marty
GitHub
parent
47e54ac110
commit
668204d953
@ -1,4 +1,4 @@
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; lzsa1fta.asm time-efficient decompressor implementation for 808x CPUs.
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; lzsa2fta.asm time-efficient decompressor implementation for 808x CPUs.
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; Turbo Assembler IDEAL mode dialect.
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; (Is supposed to also assemble with NASM's IDEAL mode support, but YMMV.)
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;
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@ -15,6 +15,7 @@
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; - Trashes all data and segment registers
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;
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; Copyright (C) 2019 Jim Leonard, Emmanuel Marty
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; Additional speed optimizations by Pavel Zagrebin
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;
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; This software is provided 'as-is', without any express or implied
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; warranty. In no event will the authors be held liable for any damages
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@ -107,7 +108,8 @@
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; the 'M' bits in the token form the value 15, and an extra byte follows here,
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; with three possible types of value.
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;
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; 0-237: the value is added to the 15 stored in the token. The final value is 3 + 15 + this byte.
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; 0-237: the value is added to the 15 stored in the token.
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; The final value is 3 + 15 + this byte.
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; 239: a second byte follows. The final match length is 256 + the second byte.
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; 238: a second and third byte follow, forming a little-endian 16-bit value.
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; The final encoded match length is that 16-bit value.
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@ -121,6 +123,14 @@
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; have the most code, but these are uncommon paths so the
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; tiny speed loss in just these paths is not a concern.
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;Setting OPTIMIZE_LONG_RLE to 1 speeds up decompressing long runs of the
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;same 16-bit word value, but hurts decompression speed of other data
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;types slightly. Turn this on if you know your data has very long 16-bit
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;word-based runs (reported as RLE2 sequences in the LZSA compressor output
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;with an average length of at least 32 bytes), otherwise leave it off.
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OPTIMIZE_LONG_RLE EQU 0
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SEGMENT CODE para public
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ASSUME cs:CODE, ds:CODE
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@ -138,43 +148,35 @@ leml2 EQU OFFSET lit_ext_mat_len_2b
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leme2 EQU OFFSET lit_ext_mat_ext_2b
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;short-circuit special cases for 0 through 6 literal copies:
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l6ml1 EQU OFFSET lit_len_mat_len_1b
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l6ml1 EQU OFFSET lit_len_mat_len_1b_6
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l6me1 EQU OFFSET lit_len_mat_ext_1b
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l6ml2 EQU OFFSET lit_len_mat_len_2b
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l6ml2 EQU OFFSET lit_len_mat_len_2b_6
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l6me2 EQU OFFSET lit_len_mat_ext_2b
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l5ml1 EQU OFFSET lit_len_mat_len_1b + 1
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l5ml1 EQU OFFSET lit_len_mat_len_1b_45
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l5me1 EQU OFFSET lit_len_mat_ext_1b + 1
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l5ml2 EQU OFFSET lit_len_mat_len_2b + 1
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l5ml2 EQU OFFSET lit_len_mat_len_2b_45
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l5me2 EQU OFFSET lit_len_mat_ext_2b + 1
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l4ml1 EQU OFFSET lit_len_mat_len_1b + 2
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l4ml1 EQU OFFSET lit_len_mat_len_1b_45 + 1
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l4me1 EQU OFFSET lit_len_mat_ext_1b + 2
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l4ml2 EQU OFFSET lit_len_mat_len_2b + 2
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l4ml2 EQU OFFSET lit_len_mat_len_2b_45 + 1
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l4me2 EQU OFFSET lit_len_mat_ext_2b + 2
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l3ml1 EQU OFFSET lit_len_mat_len_1b + 3
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l3ml1 EQU OFFSET lit_len_mat_len_1b_23
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l3me1 EQU OFFSET lit_len_mat_ext_1b + 3
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l3ml2 EQU OFFSET lit_len_mat_len_2b + 3
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l3ml2 EQU OFFSET lit_len_mat_len_2b_23
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l3me2 EQU OFFSET lit_len_mat_ext_2b + 3
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l2ml1 EQU OFFSET lit_len_mat_len_1b + 4
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l2ml1 EQU OFFSET lit_len_mat_len_1b_23 + 1
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l2me1 EQU OFFSET lit_len_mat_ext_1b + 4
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l2ml2 EQU OFFSET lit_len_mat_len_2b + 4
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l2ml2 EQU OFFSET lit_len_mat_len_2b_23 + 1
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l2me2 EQU OFFSET lit_len_mat_ext_2b + 4
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l1ml1 EQU OFFSET lit_len_mat_len_1b + 5
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l1ml1 EQU OFFSET lit_len_mat_len_1b_01
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l1me1 EQU OFFSET lit_len_mat_ext_1b + 5
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l1ml2 EQU OFFSET lit_len_mat_len_2b + 5
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l1ml2 EQU OFFSET lit_len_mat_len_2b_01
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l1me2 EQU OFFSET lit_len_mat_ext_2b + 5
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l0ml1 EQU OFFSET lit_len_mat_len_1b + 6 ; MMMM handling comes after LLL code
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l0me1 EQU OFFSET lit_len_mat_ext_1b + 6 ; MMMM handling comes after LLL code
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l0ml2 EQU OFFSET lit_len_mat_len_2b + 6 ; MMMM handling comes after LLL code
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l0me2 EQU OFFSET lit_len_mat_ext_2b + 6 ; MMMM handling comes after LLL code
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l0ml1 EQU OFFSET lit_len_mat_len_1b_01 + 1 ; MMMM handling comes after LLL code
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l0me1 EQU OFFSET lit_len_mat_ext_1b + 6 ; MMMM handling comes after LLL code
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l0ml2 EQU OFFSET lit_len_mat_len_2b_01 + 1 ; MMMM handling comes after LLL code
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l0me2 EQU OFFSET lit_len_mat_ext_2b + 6 ; MMMM handling comes after LLL code
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; === Hand-written (!) jumptable actually begins here.
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; Located before the program code results in an extra JMP and 3 wasted bytes,
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; but it makes the code easier to follow in this location.
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; Relocate the jump table after the ENDP directive to save 3 bytes.
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;
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; 7 6 5 4 3 2 1 0
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; O L L L M M M M
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;
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; 0 1 2 3 4 5 6 7 8 9 a b c d e f
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jtbl DW l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0ml1,l0me1 ;0
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DW l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1ml1,l1me1 ;1
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@ -215,7 +217,7 @@ MACRO get_word_match_offset
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ENDM
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MACRO do_match_copy_long
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LOCAL do_run, do_run_w
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LOCAL even0,even1,even2,do_run,do_run_w
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; Copies a long match as optimally as possible.
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; requirements: cx=length, bp=negative offset, ds:si=compdata, es:di=output
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; trashes: ax, bx
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@ -226,45 +228,52 @@ LOCAL do_run, do_run_w
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xchg ax,si ;save si
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lea si,[bp+di] ;si = output buffer + negative match offset
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cmp bp,-2 ;do we have a byte/word run to optimize?
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jae do_run ;perform a run if so, otherwise fall through
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;You may be tempted to change "jae" to "jge" because DX is a signed number.
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;Don't! The total window is 64k, so if you treat this as a signed comparison,
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;you will get incorrect results for offsets over 32K.
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IF OPTIMIZE_LONG_RLE
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jae do_run ;catch offset = -2 or -1
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ELSE
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ja do_run ;catch offset = -1
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ENDIF
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;If we're here, we have a long copy and it isn't byte-overlapping (if it
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;overlapped, we'd be in @@do_run) So, let's copy faster with REP MOVSW.
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;This affects 8088 only slightly, but is a bigger win on 8086 and higher.
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shr cx,1
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jnc even0
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movsb
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even0:
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rep movsw
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adc cl,0
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rep movsb
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xchg si,ax ;restore si
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mov ds,bx ;restore ds
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jmp decode_token
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do_run:
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IF OPTIMIZE_LONG_RLE
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je do_run_w ;if applicable, handle word-sized value faster
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ENDIF
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xchg dx,ax ;save si into dx, as ax is getting trashed
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lodsb ;load first byte of run into al
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mov ah,al
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shr cx,1
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jnc even1
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stosb
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even1:
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rep stosw ;perform word run
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adc cl,0
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rep stosb ;finish word run
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mov si,dx ;restore si
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mov ds,bx ;restore ds
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jmp decode_token
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IF OPTIMIZE_LONG_RLE
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do_run_w:
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xchg dx,ax ;save si into dx, as ax is getting trashed
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lodsw ;load first word of run
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shr cx,1
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rep stosw ;perform word run
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adc cl,0 ;despite 2-byte offset, compressor might
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rep stosb ;output odd length. better safe than sorry.
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jnc even2
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stosb ;should be after rep stosw!
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even2:
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mov si,dx ;restore si
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mov ds,bx ;restore ds
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jmp decode_token
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ENDIF
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ENDM
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MACRO do_match_copy
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@ -277,6 +286,9 @@ MACRO do_match_copy
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mov ds,ax ;ds=es
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xchg ax,si ;save si
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lea si,[bp+di] ;si = output buffer + negative match offset
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movsb
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movsb
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movsb ;Handle MINMATCH (instead of add cx,MINMATCH)
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rep movsb
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xchg si,ax ;restore si
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mov ds,bx ;restore ds
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@ -284,34 +296,36 @@ MACRO do_match_copy
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ENDM
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MACRO do_literal_copy
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LOCAL even
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; Copies a literal sequence using words.
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; Meant for longer lengths; for 128 bytes or less, use REP MOVSB.
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; requirements: cx=length, ds:si=compdata, es:di=output
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; must leave cx=0 at exit
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shr cx,1
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jnc even
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movsb
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even:
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rep movsw
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adc cl,0
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rep movsb
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ENDM
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MACRO copy_small_match_len
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and al,0FH ;isolate length in token (MMMM)
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add al,minmatch ;ax=match length
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xchg cx,ax ;cx=match length
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do_match_copy ;copy match with cx=length, bp=offset
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ENDM
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MACRO copy_large_match_len
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LOCAL val239, val238, EOD
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LOCAL val239,val238,EOD
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; Handle MMMM=Fh
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; Assumptions: ah=0 from get_????_match_offset's xchg
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lodsb ;grab extra match length byte
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add al,0Fh+minmatch ;add MATCH_RUN_LEN + MIN_MATCH_SIZE
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jz val238 ;if zf & cf, 238: get 16-bit match length
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; jz val238 ;if zf & cf, 238: get 16-bit match length
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jc val239 ;if cf, 239: get extra match length byte
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xchg cx,ax ;otherwise, we have our match length
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do_match_copy_long ;copy match with cx=length, bp=offset
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val239:
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jz val238
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lodsb ;ah=0; grab single extra length byte
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inc ah ;ax=256+length byte
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xchg cx,ax
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@ -347,16 +361,27 @@ decode_token:
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; Path #1: LLL=0-6, MMMM=0-Eh, O=0 (1-byte match offset)
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; Handle LLL=0-6 by jumping directly into # of bytes to copy (6 down to 1)
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lit_len_mat_len_1b:
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movsb
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movsb
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movsb
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movsb
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movsb
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lit_len_mat_len_1b_01:
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movsb
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get_byte_match_offset
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copy_small_match_len
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lit_len_mat_len_1b_23:
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movsb
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movsw
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get_byte_match_offset
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copy_small_match_len
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lit_len_mat_len_1b_45:
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movsb
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movsw
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movsw
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get_byte_match_offset
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copy_small_match_len
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lit_len_mat_len_1b_6:
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movsw
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movsw
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movsw
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get_byte_match_offset
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copy_small_match_len
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; Path #2: LLL=0-6, MMMM=Fh, O=0 (1-byte match offset)
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lit_len_mat_ext_1b:
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@ -375,13 +400,14 @@ lit_ext_mat_len_1b:
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; on entry: ax=0 + token, bp=ax
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lodsb ;grab extra literal length byte
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add al,litrunlen ;add 7h literal run length
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jz @@val249_3 ;if zf & cf, 249: get 16-bit literal length
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; jz @@val249_3 ;if zf & cf, 249: get 16-bit literal length
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jc @@val250_3 ;if cf, 250: get extra literal length byte
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xchg cx,ax ;otherwise, we have our literal length
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do_literal_copy ;this might be better as rep movsw !!! benchmark
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get_byte_match_offset
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copy_small_match_len
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@@val250_3:
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jz @@val249_3
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lodsb ;ah=0; grab single extra length byte
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inc ah ;ax=256+length byte
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xchg cx,ax
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@ -401,13 +427,14 @@ lit_ext_mat_ext_1b:
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; on entry: ax=0 + token, bp=ax
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lodsb ;grab extra literal length byte
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add al,litrunlen ;add 7h literal run length
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jz @@val249_4 ;if zf & cf, 249: get 16-bit literal length
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; jz @@val249_4 ;if zf & cf, 249: get 16-bit literal length
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jc @@val250_4 ;if cf, 250: get extra literal length byte
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xchg cx,ax ;otherwise, we have our literal length
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do_literal_copy ;this might be better as rep movsw !!! benchmark
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get_byte_match_offset
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copy_large_match_len
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@@val250_4:
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jz @@val249_4
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lodsb ;ah=0; grab single extra length byte
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inc ah ;ax=256+length byte
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xchg cx,ax
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@ -424,17 +451,30 @@ lit_ext_mat_ext_1b:
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; Path #5: LLL=0-6, MMMM=0-Eh, O=1 (2-byte match offset)
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; Handle LLL=0-6 by jumping directly into # of bytes to copy (6 down to 1)
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lit_len_mat_len_2b:
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movsb
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movsb
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movsb
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lit_len_mat_len_2b_01:
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movsb
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get_word_match_offset
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copy_small_match_len
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lit_len_mat_len_2b_23:
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movsb
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movsw
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get_word_match_offset
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copy_small_match_len
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lit_len_mat_len_2b_45:
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movsb
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movsw
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movsw
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get_word_match_offset
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copy_small_match_len
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lit_len_mat_len_2b_6:
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movsw
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movsw
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movsw
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get_word_match_offset
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copy_small_match_len
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; Path #6: LLL=0-6, MMMM=Fh, O=1 (2-byte match offset)
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; Path #6: LLL=0-6, MMMM=Fh, O=1 (2-byte match offset)
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lit_len_mat_ext_2b:
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movsb
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@ -446,19 +486,19 @@ lit_len_mat_ext_2b:
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get_word_match_offset
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copy_large_match_len
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; Path #7: LLL=7, MMMM=0-Eh, O=1 (2-byte match offset)
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lit_ext_mat_len_2b:
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; on entry: ax=0 + token, bp=ax
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lodsb ;grab extra literal length byte
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add al,litrunlen ;add 7h literal run length
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jz @@val249_7 ;if zf & cf, 249: get 16-bit literal length
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; jz @@val249_7 ;if zf & cf, 249: get 16-bit literal length
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jc @@val250_7 ;if cf, 250: get extra literal length byte
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xchg cx,ax ;otherwise, we have our literal length
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do_literal_copy ;this might be better as rep movsw !!! benchmark
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get_word_match_offset
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copy_small_match_len
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@@val250_7:
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jz @@val249_7
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lodsb ;ah=0; grab single extra length byte
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inc ah ;ax=256+length byte
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xchg cx,ax
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@ -478,13 +518,14 @@ lit_ext_mat_ext_2b:
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; on entry: ax=0 + token, bp=ax
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lodsb ;grab extra literal length byte
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add al,litrunlen ;add 7h literal run length
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jz @@val249_8 ;if zf & cf, 249: get 16-bit literal length
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; jz @@val249_8 ;if zf & cf, 249: get 16-bit literal length
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jc @@val250_8 ;if cf, 250: get extra literal length byte
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xchg cx,ax ;otherwise, we have our literal length
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do_literal_copy ;this might be better as rep movsw !!! benchmark
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get_word_match_offset
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copy_large_match_len
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@@val250_8:
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jz @@val249_8
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lodsb ;ah=0; grab single extra length byte
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inc ah ;ax=256+length byte
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xchg cx,ax
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@ -512,6 +553,8 @@ ENDS CODE
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END
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;Speed optimization history (decompression times in microseconds @ 4.77 MHz):
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; defer add MIN_MATCH_SIZE shuttle 97207 alice 57200 robotron 362884 ++*
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; jumptable rewrite, no RLE shuttle 97744 alice 46905 robotron 309032 -++
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@ -521,3 +564,18 @@ END
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; long match copy #1 16-bit shuttle 92490 alice 46905 robotron 308722 +*+
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; long match copy #2 extraB shuttle 92464 alice 46905 robotron 308371 +.+
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; long match copy #3 0f->ed shuttle 86765 alice 46864 robotron 303895 +++!
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; baseline new test harness shuttle 83925 alice 37948 robotron 269002 ***
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; Pavel optimizations shuttle 82225 alice 36798 robotron 261226 +++
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; OPTIMIZE_LONG_RLE 1 shuttle 82242 alice 36787 robotron 261392 **-
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;
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;------
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;
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;Pavel's optimization history:
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; shuttle alice robotron time in 1.193 MHz timer clocks
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;baseline 19109 D9A6 570F6
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;adc cl,0->adc cl,cl 19035 D9A6 56FAB
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;rep movsb->shr cx,1;jnc 18FD4 D998 56F14
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;cmp bp,-2->inc bp;inc bp 18F07 D999 56EA3
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;jz;jc->jc 18D81 D973 56B2F
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;add al,3->movsb x3 18B1E D777 56197
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;more lit_len_mat tables 18A83 D341 54ACC
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