6502/lzsa
1
0
Fork 0
mirror of https://github.com/emmanuel-marty/lzsa.git synced 2024-11-22 05:33:58 +00:00
Code Issues Projects Releases Wiki Activity

Merge pull request #16 from peterferrie/master - thanks!

Browse Source 
smaller
This commit is contained in:
Emmanuel Marty 2019-07-12 10:34:58 +02:00 committed by GitHub
commit 6445d9ff6f
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 34 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
asm/6502/decompress_v1.asm
View File

@ -42,7 +42,7 @@ DECODE_TOKEN
LSR A
LSR A
CMP #$07 ; LITERALS_RUN_LEN?
BNE PREPARE_COPY_LITERALS ; if not, count is directly embedded in token
BCC PREPARE_COPY_LITERALS ; if not, count is directly embedded in token
JSR GETSRC ; get extra byte of variable literals count
; the carry is always set by the CMP above
@ -62,7 +62,6 @@ LARGE_VARLEN_LITERALS ; handle 16 bits literals count
BYTE $A9 ; mask TAX (faster than BCS)
PREPARE_COPY_LITERALS
TAX
PREPARE_COPY_LITERALS_HIGH
INY
COPY_LITERALS
@ -95,7 +94,8 @@ PREPARE_COPY_MATCH_Y
COPY_MATCH_LOOP
LDA $AAAA ; get one byte of backreference
INC COPY_MATCH_LOOP+1
BEQ GETMATCH_INC_HI
BNE GETMATCH_DONE
INC COPY_MATCH_LOOP+2
GETMATCH_DONE
JSR PUTDST ; copy to destination
DEX
@ -104,10 +104,6 @@ GETMATCH_DONE
BNE COPY_MATCH_LOOP
BEQ DECODE_TOKEN ; (*like JMP DECODE_TOKEN but shorter)
GETMATCH_INC_HI
INC COPY_MATCH_LOOP+2
BNE GETMATCH_DONE ; (*like JMP GETMATCH_DONE but shorter)
GET_LONG_OFFSET ; handle 16 bit offset:
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
@ -128,7 +124,7 @@ OFFSHI = *+1
AND #$0F ; isolate match len (MMMM)
ADC #$02 ; plus carry which is always set by the high ADC
CMP #$12 ; MATCH_RUN_LEN?
BNE PREPARE_COPY_MATCH ; if not, count is directly embedded in token
BCC PREPARE_COPY_MATCH ; if not, count is directly embedded in token
JSR GETSRC ; get extra byte of variable match length
; the carry is always set by the CMP above
@ -142,7 +138,7 @@ OFFSHI = *+1
TAY ; put high 8 bits in Y
; large match length with zero high byte?
BNE PREPARE_COPY_MATCH_Y ; if not, continue
; (*like JMP PREPARE_COPY_MATCH_Y but shorter)
DECOMPRESSION_DONE
RTS
@ -153,11 +149,9 @@ LZSA_DST_LO = *+1
LZSA_DST_HI = *+2
STA $AAAA
INC PUTDST+1
BEQ PUTDST_INC_HI
PUTDST_DONE
RTS
PUTDST_INC_HI
BNE PUTDST_DONE
INC PUTDST+2
PUTDST_DONE
RTS
GETLARGESRC
@ -170,9 +164,7 @@ LZSA_SRC_LO = *+1
LZSA_SRC_HI = *+2
LDA $AAAA
INC GETSRC+1
BEQ GETSRC_INC_HI
BNE GETSRC_DONE
INC GETSRC+2
GETSRC_DONE
RTS
GETSRC_INC_HI
INC GETSRC+2
RTS

54
asm/6502/decompress_v2.asm
View File

@ -41,34 +41,32 @@ DECODE_TOKEN
AND #$18 ; isolate literals count (LL)
BEQ NO_LITERALS ; skip if no literals to copy
CMP #$18 ; LITERALS_RUN_LEN_V2 << 3?
BNE EMBEDDED_LITERALS ; if less, count is directly embedded in token
LSR A ; shift literals count into place
LSR A
LSR A
CMP #$03 ; LITERALS_RUN_LEN_V2?
BCC PREPARE_COPY_LITERALS ; if less, count is directly embedded in token
JSR GETNIBBLE ; get extra literals length nibble
; add nibble to len from token
ADC #$02 ; (LITERALS_RUN_LEN_V2) minus carry
CMP #$12 ; LITERALS_RUN_LEN_V2 + 15 ?
BNE PREPARE_COPY_LITERALS ; if less, literals count is complete
BCC PREPARE_COPY_LITERALS ; if less, literals count is complete
JSR GETSRC ; get extra byte of variable literals count
; the carry is always set by the CMP above
; GETSRC doesn't change it
SBC #$EE ; overflow?
BCC PREPARE_COPY_LITERALS ; if not, literals count is complete
PREPARE_COPY_LITERALS
TAX
BCC PREPARE_COPY_LITERALS_HIGH ; if not, literals count is complete
; handle 16 bits literals count
; literals count = directly these 16 bits
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
TAY ; put high 8 bits in Y
BCS PREPARE_COPY_LITERALS_HIGH ; (*like JMP PREPARE_COPY_LITERALS_HIGH but shorter)
EMBEDDED_LITERALS
LSR A ; shift literals count into place
LSR A
LSR A
PREPARE_COPY_LITERALS
TAX
PREPARE_COPY_LITERALS_HIGH
INY
@ -144,35 +142,36 @@ OFFSHI = *+1
AND #$07 ; isolate match len (MMM)
ADC #$01 ; add MIN_MATCH_SIZE_V2 and carry
CMP #$09 ; MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2?
BNE PREPARE_COPY_MATCH ; if less, length is directly embedded in token
BCC PREPARE_COPY_MATCH ; if less, length is directly embedded in token
JSR GETNIBBLE ; get extra match length nibble
; add nibble to len from token
ADC #$08 ; (MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2) minus carry
CMP #$18 ; MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2 + 15?
BNE PREPARE_COPY_MATCH ; if less, match length is complete
BCC PREPARE_COPY_MATCH ; if less, match length is complete
JSR GETSRC ; get extra byte of variable match length
; the carry is always set by the CMP above
; GETSRC doesn't change it
SBC #$E8 ; overflow?
BCC PREPARE_COPY_MATCH ; if not, the match length is complete
PREPARE_COPY_MATCH
TAX
BCC PREPARE_COPY_MATCH_Y ; if not, the match length is complete
BEQ DECOMPRESSION_DONE ; if EOD code, bail
; Handle 16 bits match length
JSR GETLARGESRC ; grab low 8 bits in X, high 8 bits in A
TAY ; put high 8 bits in Y
BYTE $A9 ; mask TAX, faster than TXA/TAX
PREPARE_COPY_MATCH
TAX
PREPARE_COPY_MATCH_Y
INY
COPY_MATCH_LOOP
LDA $AAAA ; get one byte of backreference
INC COPY_MATCH_LOOP+1
BEQ GETMATCH_INC_HI
BNE GETMATCH_DONE
INC COPY_MATCH_LOOP+2
GETMATCH_DONE
JSR PUTDST ; copy to destination
DEX
@ -180,9 +179,6 @@ GETMATCH_DONE
DEY
BNE COPY_MATCH_LOOP
JMP DECODE_TOKEN
GETMATCH_INC_HI
INC COPY_MATCH_LOOP+2
BNE GETMATCH_DONE ; (*like JMP GETMATCH_DONE but shorter)
GETCOMBINEDBITS
EOR #$80
@ -193,6 +189,7 @@ GETCOMBINEDBITS
PLP ; merge Z bit as the carry bit (for offset bit 0)
COMBINEDBITZ
ROL ; nibble -> bits 1-4; carry(!Z bit) -> bit 0 ; carry cleared
DECOMPRESSION_DONE
RTS
GETNIBBLE
@ -221,12 +218,9 @@ LZSA_DST_LO = *+1
LZSA_DST_HI = *+2
STA $AAAA
INC PUTDST+1
BEQ PUTDST_INC_HI
PUTDST_DONE
DECOMPRESSION_DONE
RTS
PUTDST_INC_HI
BNE PUTDST_DONE
INC PUTDST+2
PUTDST_DONE
RTS
GETLARGESRC
@ -239,9 +233,7 @@ LZSA_SRC_LO = *+1
LZSA_SRC_HI = *+2
LDA $AAAA
INC GETSRC+1
BEQ GETSRC_INC_HI
BNE GETSRC_DONE
INC GETSRC+2
GETSRC_DONE
RTS
GETSRC_INC_HI
INC GETSRC+2
RTS

4
asm/8088/decompress_small_v2.S
View File

@ -89,8 +89,8 @@ lzsa2_decompress:
jmp short .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)
jnb .rep_match_or_16_bit
;;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