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Merge pull request #7 from emmanuel-marty/master
Synchronize with the head repository
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introspec
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4eae728e56
@ -7,12 +7,9 @@
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;
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; This code is written for the ACME assembler.
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;
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; Optional code is presented for one minor 6502 optimization that breaks
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; compatibility with the current LZSA1 format standard.
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; The code is 167 bytes for the small version, and 192 bytes for the normal.
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;
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; The code is 168 bytes for the small version, and 205 bytes for the normal.
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;
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; Copyright John Brandwood 2019.
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; Copyright John Brandwood 2021.
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;
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; Distributed under the Boost Software License, Version 1.0.
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; (See accompanying file LICENSE_1_0.txt or copy at
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@ -30,80 +27,11 @@
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;
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;
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; Choose size over space (within sane limits)?
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; Choose size over decompression speed (within sane limits)?
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;
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LZSA_SMALL_SIZE = 0
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;
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; Remove code inlining to save space?
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;
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; This saves 15 bytes of code at the cost of 7% speed.
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;
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!if LZSA_SMALL_SIZE {
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LZSA_NO_INLINE = 1
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} else {
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LZSA_NO_INLINE = 0
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}
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;
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; Use smaller code for copying literals?
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;
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; This saves 11 bytes of code at the cost of 15% speed.
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;
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!if LZSA_SMALL_SIZE {
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LZSA_SHORT_CP = 1
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} else {
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LZSA_SHORT_CP = 0
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}
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;
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; Use smaller code for copying literals?
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;
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; This saves 11 bytes of code at the cost of 30% speed.
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;
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!if LZSA_SMALL_SIZE {
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LZSA_SHORT_LZ = 1
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} else {
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LZSA_SHORT_LZ = 0
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}
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;
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; Macro to increment the source pointer to the next page.
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;
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; This should call a subroutine to determine if a bank
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; has been crossed, and a new bank should be paged in.
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;
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!macro LZSA_INC_PAGE {
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inc <lzsa_srcptr + 1
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}
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;
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; Macro to read a byte from the compressed source data.
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;
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!if LZSA_NO_INLINE {
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!macro LZSA_GET_SRC {
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jsr lzsa1_get_byte
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}
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} else {
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!macro LZSA_GET_SRC {
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lda (lzsa_srcptr),y
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inc <lzsa_srcptr + 0
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bne .skip
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+LZSA_INC_PAGE
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.skip:
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}
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}
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; ***************************************************************************
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@ -112,10 +40,7 @@ LZSA_SHORT_LZ = 0
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; Data usage is last 8 bytes of zero-page.
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;
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!if (LZSA_SHORT_CP | LZSA_SHORT_LZ) {
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lzsa_length = $F8 ; 1 byte.
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}
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lzsa_cmdbuf = $F9 ; 1 byte.
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lzsa_winptr = $FA ; 1 word.
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lzsa_srcptr = $FC ; 1 word.
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@ -127,6 +52,7 @@ LZSA_DST_LO = $FE
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LZSA_DST_HI = $FF
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; ***************************************************************************
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; ***************************************************************************
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;
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@ -147,118 +73,114 @@ lzsa1_unpack: ldy #0 ; Initialize source index.
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; N.B. X=0 is expected and guaranteed when we get here.
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;
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.cp_length: +LZSA_GET_SRC
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sta <lzsa_cmdbuf ; Preserve this for later.
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.cp_length: !if LZSA_SMALL_SIZE {
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jsr .get_byte
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} else {
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lda (lzsa_srcptr),y
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inc <lzsa_srcptr + 0
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bne .cp_skip0
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inc <lzsa_srcptr + 1
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}
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.cp_skip0: sta <lzsa_cmdbuf ; Preserve this for later.
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and #$70 ; Extract literal length.
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lsr ; Set CC before ...
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beq .lz_offset ; Skip directly to match?
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lsr ; Get 3-bit literal length.
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lsr
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lsr
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lsr
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cmp #$07 ; Extended length?
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bne .got_cp_len
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bcc .inc_cp_len
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jsr .get_length ; CS from CMP, X=0.
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!if LZSA_SHORT_CP {
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ora #0 ; Check the lo-byte of length
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beq .put_cp_len ; without effecting CC.
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.got_cp_len: cmp #0 ; Check the lo-byte of length.
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beq .put_cp_len
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inx ; Increment # of pages to copy.
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.inc_cp_len: inx ; Increment # of pages to copy.
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.put_cp_len: stx <lzsa_length
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tax
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.cp_page: lda (lzsa_srcptr),y
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sta (lzsa_dstptr),y
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.cp_page: lda (lzsa_srcptr),y ; CC throughout the execution of
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sta (lzsa_dstptr),y ; of this .cp_page loop.
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inc <lzsa_srcptr + 0
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bne .skip1
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bne .cp_skip1
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inc <lzsa_srcptr + 1
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.skip1: inc <lzsa_dstptr + 0
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bne .skip2
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.cp_skip1: inc <lzsa_dstptr + 0
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bne .cp_skip2
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inc <lzsa_dstptr + 1
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.skip2: dex
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.cp_skip2: dex
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bne .cp_page
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dec <lzsa_length ; Any full pages left to copy?
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bne .cp_page
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} else {
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.got_cp_len: tay ; Check the lo-byte of length.
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beq .cp_page
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inx ; Increment # of pages to copy.
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.get_cp_src: clc ; Calc address of partial page.
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adc <lzsa_srcptr + 0
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sta <lzsa_srcptr + 0
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bcs .get_cp_dst
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dec <lzsa_srcptr + 1
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.get_cp_dst: tya
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clc ; Calc address of partial page.
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adc <lzsa_dstptr + 0
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sta <lzsa_dstptr + 0
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bcs .get_cp_idx
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dec <lzsa_dstptr + 1
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.get_cp_idx: tya ; Negate the lo-byte of length.
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eor #$FF
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tay
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iny
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.cp_page: lda (lzsa_srcptr),y
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sta (lzsa_dstptr),y
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iny
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bne .cp_page
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inc <lzsa_srcptr + 1
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inc <lzsa_dstptr + 1
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dex ; Any full pages left to copy?
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bne .cp_page
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}
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;
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; Copy bytes from decompressed window.
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;
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; N.B. X=0 is expected and guaranteed when we get here.
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;
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.lz_offset: +LZSA_GET_SRC
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clc
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adc <lzsa_dstptr + 0
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.lz_offset: !if LZSA_SMALL_SIZE {
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jsr .get_byte
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} else {
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lda (lzsa_srcptr),y
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inc <lzsa_srcptr + 0
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bne .offset_lo
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inc <lzsa_srcptr + 1
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}
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.offset_lo: adc <lzsa_dstptr + 0 ; Always CC from .cp_page loop.
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sta <lzsa_winptr + 0
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lda #$FF
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bit <lzsa_cmdbuf
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bpl .hi_offset
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+LZSA_GET_SRC
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bpl .offset_hi
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.hi_offset: adc <lzsa_dstptr + 1
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sta <lzsa_winptr + 1
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!if LZSA_SMALL_SIZE {
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jsr .get_byte
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} else {
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lda (lzsa_srcptr),y
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inc <lzsa_srcptr + 0
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bne .offset_hi
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inc <lzsa_srcptr + 1
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}
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.offset_hi: adc <lzsa_dstptr + 1 ; lzsa_winptr < lzsa_dstptr, so
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sta <lzsa_winptr + 1 ; always leaves CS.
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!if LZSA_SMALL_SIZE {
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.lz_length: lda <lzsa_cmdbuf ; X=0 from previous loop.
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and #$0F
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adc #$03 - 1 ; CS from previous ADC.
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cmp #$12 ; Extended length?
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bne .got_lz_len
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bcc .inc_lz_len
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jsr .get_length ; CS from CMP, X=0.
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jsr .get_length ; CS from CMP, X=0, returns CC.
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!if LZSA_SHORT_LZ {
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ora #0 ; Check the lo-byte of length
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beq .put_lz_len ; without effecting CC.
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.got_lz_len: cmp #0 ; Check the lo-byte of length.
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beq .put_lz_len
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inx ; Increment # of pages to copy.
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.inc_lz_len: inx ; Increment # of pages to copy.
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.put_lz_len: stx <lzsa_length
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tax
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.lz_page: lda (lzsa_winptr),y
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sta (lzsa_dstptr),y
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.lz_page: lda (lzsa_winptr),y ; CC throughout the execution of
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sta (lzsa_dstptr),y ; of this .lz_page loop.
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inc <lzsa_winptr + 0
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bne .skip3
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inc <lzsa_winptr + 1
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@ -274,19 +196,26 @@ lzsa1_unpack: ldy #0 ; Initialize source index.
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} else {
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.lz_length: lda <lzsa_cmdbuf ; X=0 from previous loop.
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and #$0F
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adc #$03 - 1 ; CS from previous ADC.
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cmp #$12 ; Extended length?
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bcc .got_lz_len
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jsr .get_length ; CS from CMP, X=0, returns CC.
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.got_lz_len: tay ; Check the lo-byte of length.
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beq .lz_page
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inx ; Increment # of pages to copy.
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.get_lz_win: clc ; Calc address of partial page.
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adc <lzsa_winptr + 0
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sta <lzsa_winptr + 0
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.get_lz_win: adc <lzsa_winptr + 0 ; Calc address of partial page.
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sta <lzsa_winptr + 0 ; Always CC from previous CMP.
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bcs .get_lz_dst
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dec <lzsa_winptr + 1
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.get_lz_dst: tya
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clc ; Calc address of partial page.
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.get_lz_dst: tya ; Calc address of partial page.
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clc
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adc <lzsa_dstptr + 0
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sta <lzsa_dstptr + 0
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bcs .get_lz_idx
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@ -311,7 +240,7 @@ lzsa1_unpack: ldy #0 ; Initialize source index.
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}
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;
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; Get 16-bit length in X:A register pair.
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; Get 16-bit length in X:A register pair, return with CC.
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;
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; N.B. X=0 is expected and guaranteed when we get here.
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;
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@ -320,31 +249,30 @@ lzsa1_unpack: ldy #0 ; Initialize source index.
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adc (lzsa_srcptr),y ; the length.
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inc <lzsa_srcptr + 0
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bne .skip_inc
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+LZSA_INC_PAGE
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inc <lzsa_srcptr + 1
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.skip_inc: bcc .got_length ; No overflow means done.
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cmp #$00 ; Overflow to 256 or 257?
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beq .extra_word
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cmp #$01 ; Overflow to 256 or 257?
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bcc .extra_word
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.extra_byte: inx
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jmp lzsa1_get_byte ; So rare, this can be slow!
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.extra_byte: clc ; MUST return CC!
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inx
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bne .get_byte ; Always NZ from previous INX.
|
||||
|
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.extra_word: jsr lzsa1_get_byte ; So rare, this can be slow!
|
||||
.extra_word: jsr .get_byte ; So rare, this can be slow!
|
||||
pha
|
||||
jsr lzsa1_get_byte ; So rare, this can be slow!
|
||||
jsr .get_byte ; So rare, this can be slow!
|
||||
tax
|
||||
beq .finished ; Length-hi == 0 at EOF.
|
||||
pla ; Length-lo.
|
||||
rts
|
||||
|
||||
lzsa1_get_byte:
|
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lda (lzsa_srcptr),y ; Subroutine version for when
|
||||
.get_byte: lda (lzsa_srcptr),y ; Subroutine version for when
|
||||
inc <lzsa_srcptr + 0 ; inlining isn't advantageous.
|
||||
beq lzsa1_next_page
|
||||
beq .next_page
|
||||
.got_length: rts
|
||||
|
||||
lzsa1_next_page:
|
||||
inc <lzsa_srcptr + 1 ; Inc & test for bank overflow.
|
||||
.next_page: inc <lzsa_srcptr + 1 ; Inc & test for bank overflow.
|
||||
rts
|
||||
|
||||
.finished: pla ; Length-lo.
|
||||
|
||||
@ -7,12 +7,9 @@
|
||||
;
|
||||
; This code is written for the ACME assembler.
|
||||
;
|
||||
; Optional code is presented for two minor 6502 optimizations that break
|
||||
; compatibility with the current LZSA2 format standard.
|
||||
; The code is 240 bytes for the small version, and 255 bytes for the normal.
|
||||
;
|
||||
; The code is 241 bytes for the small version, and 267 bytes for the normal.
|
||||
;
|
||||
; Copyright John Brandwood 2019.
|
||||
; Copyright John Brandwood 2021.
|
||||
;
|
||||
; Distributed under the Boost Software License, Version 1.0.
|
||||
; (See accompanying file LICENSE_1_0.txt or copy at
|
||||
@ -30,99 +27,11 @@
|
||||
;
|
||||
|
||||
;
|
||||
; Choose size over space (within sane limits)?
|
||||
; Choose size over decompression speed (within sane limits)?
|
||||
;
|
||||
|
||||
LZSA_SMALL_SIZE = 0
|
||||
|
||||
;
|
||||
; Remove code inlining to save space?
|
||||
;
|
||||
; This saves 15 bytes of code at the cost of 7% speed.
|
||||
;
|
||||
|
||||
!if LZSA_SMALL_SIZE {
|
||||
LZSA_NO_INLINE = 1
|
||||
} else {
|
||||
LZSA_NO_INLINE = 0
|
||||
}
|
||||
|
||||
;
|
||||
; Use smaller code for copying literals?
|
||||
;
|
||||
; This saves 11 bytes of code at the cost of 5% speed.
|
||||
;
|
||||
|
||||
!if LZSA_SMALL_SIZE {
|
||||
LZSA_SHORT_CP = 1
|
||||
} else {
|
||||
LZSA_SHORT_CP = 0
|
||||
}
|
||||
|
||||
;
|
||||
; We will read from or write to $FFFF. This prevents the
|
||||
; use of the "INC ptrhi / BNE" trick and reduces speed.
|
||||
;
|
||||
|
||||
LZSA_USE_FFFF = 0
|
||||
|
||||
;
|
||||
; Macro to increment the source pointer to the next page.
|
||||
;
|
||||
|
||||
!macro LZSA_INC_PAGE {
|
||||
inc <lzsa_srcptr + 1
|
||||
}
|
||||
|
||||
;
|
||||
; Macro to read a byte from the compressed source data.
|
||||
;
|
||||
|
||||
!if LZSA_NO_INLINE {
|
||||
|
||||
!macro LZSA_GET_SRC {
|
||||
jsr lzsa2_get_byte
|
||||
}
|
||||
|
||||
} else {
|
||||
|
||||
!macro LZSA_GET_SRC {
|
||||
lda (lzsa_srcptr),y
|
||||
inc <lzsa_srcptr + 0
|
||||
bne .skip
|
||||
+LZSA_INC_PAGE
|
||||
.skip:
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
;
|
||||
; Macro to speed up reading 50% of nibbles.
|
||||
;
|
||||
; This seems to save very few cycles compared to the
|
||||
; increase in code size, and it isn't recommended.
|
||||
;
|
||||
|
||||
LZSA_SLOW_NIBL = 1
|
||||
|
||||
!if (LZSA_SLOW_NIBL + LZSA_SMALL_SIZE) {
|
||||
|
||||
!macro LZSA_GET_NIBL {
|
||||
jsr lzsa2_get_nibble ; Always call a function.
|
||||
}
|
||||
|
||||
} else {
|
||||
|
||||
!macro LZSA_GET_NIBL {
|
||||
lsr <lzsa_nibflg ; Is there a nibble waiting?
|
||||
lda <lzsa_nibble ; Extract the lo-nibble.
|
||||
bcs .skip
|
||||
jsr lzsa2_new_nibble ; Extract the hi-nibble.
|
||||
.skip: ora #$F0
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
|
||||
|
||||
; ***************************************************************************
|
||||
@ -131,6 +40,8 @@ LZSA_SLOW_NIBL = 1
|
||||
; Data usage is last 11 bytes of zero-page.
|
||||
;
|
||||
|
||||
lzsa_length = lzsa_winptr ; 1 word.
|
||||
|
||||
lzsa_cmdbuf = $F5 ; 1 byte.
|
||||
lzsa_nibflg = $F6 ; 1 byte.
|
||||
lzsa_nibble = $F7 ; 1 byte.
|
||||
@ -159,49 +70,30 @@ LZSA_DST_HI = $FF
|
||||
;
|
||||
|
||||
DECOMPRESS_LZSA2_FAST:
|
||||
lzsa2_unpack: ldy #0 ; Initialize source index.
|
||||
lzsa2_unpack: ldx #$00 ; Hi-byte of length or offset.
|
||||
ldy #$00 ; Initialize source index.
|
||||
sty <lzsa_nibflg ; Initialize nibble buffer.
|
||||
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) = 0 {
|
||||
|
||||
beq .cp_length ; always taken
|
||||
.incsrc1:
|
||||
inc <lzsa_srcptr + 1
|
||||
bne .resume_src1 ; always taken
|
||||
|
||||
!if LZSA_SHORT_CP {
|
||||
.incsrc2:
|
||||
inc <lzsa_srcptr + 1
|
||||
bne .resume_src2 ; always taken
|
||||
|
||||
.incdst:
|
||||
inc <lzsa_dstptr + 1
|
||||
bne .resume_dst ; always taken
|
||||
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
;
|
||||
; Copy bytes from compressed source data.
|
||||
;
|
||||
; N.B. X=0 is expected and guaranteed when we get here.
|
||||
;
|
||||
|
||||
.cp_length: ldx #$00 ; Hi-byte of length or offset.
|
||||
.cp_length: !if LZSA_SMALL_SIZE {
|
||||
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) {
|
||||
|
||||
+LZSA_GET_SRC
|
||||
jsr .get_byte
|
||||
|
||||
} else {
|
||||
|
||||
lda (lzsa_srcptr),y
|
||||
inc <lzsa_srcptr + 0
|
||||
beq .incsrc1
|
||||
bne .cp_skip0
|
||||
inc <lzsa_srcptr + 1
|
||||
|
||||
}
|
||||
|
||||
.resume_src1:
|
||||
sta <lzsa_cmdbuf ; Preserve this for later.
|
||||
.cp_skip0: sta <lzsa_cmdbuf ; Preserve this for later.
|
||||
and #$18 ; Extract literal length.
|
||||
beq .lz_offset ; Skip directly to match?
|
||||
|
||||
@ -209,91 +101,48 @@ lzsa2_unpack: ldy #0 ; Initialize source index.
|
||||
lsr
|
||||
lsr
|
||||
cmp #$03 ; Extended length?
|
||||
bne .got_cp_len
|
||||
bcc .inc_cp_len
|
||||
|
||||
jsr .get_length ; X=0 table index for literals.
|
||||
inx
|
||||
jsr .get_length ; X=1 for literals, returns CC.
|
||||
|
||||
!if LZSA_SHORT_CP {
|
||||
ora #0 ; Check the lo-byte of length
|
||||
beq .put_cp_len ; without effecting CC.
|
||||
|
||||
.got_cp_len: cmp #0 ; Check the lo-byte of length.
|
||||
beq .put_cp_len
|
||||
|
||||
inx ; Increment # of pages to copy.
|
||||
.inc_cp_len: inx ; Increment # of pages to copy.
|
||||
|
||||
.put_cp_len: stx <lzsa_length
|
||||
tax
|
||||
|
||||
.cp_page: lda (lzsa_srcptr),y
|
||||
sta (lzsa_dstptr),y
|
||||
.cp_page: lda (lzsa_srcptr),y ; CC throughout the execution of
|
||||
sta (lzsa_dstptr),y ; of this .cp_page loop.
|
||||
|
||||
inc <lzsa_srcptr + 0
|
||||
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) {
|
||||
|
||||
bne .skip1
|
||||
bne .cp_skip1
|
||||
inc <lzsa_srcptr + 1
|
||||
.skip1: inc <lzsa_dstptr + 0
|
||||
bne .skip2
|
||||
|
||||
.cp_skip1: inc <lzsa_dstptr + 0
|
||||
bne .cp_skip2
|
||||
inc <lzsa_dstptr + 1
|
||||
.skip2:
|
||||
|
||||
} else {
|
||||
|
||||
beq .incsrc2
|
||||
.resume_src2:
|
||||
inc <lzsa_dstptr + 0
|
||||
beq .incdst
|
||||
.resume_dst:
|
||||
|
||||
}
|
||||
|
||||
dex
|
||||
.cp_skip2: dex
|
||||
bne .cp_page
|
||||
dec <lzsa_length ; Any full pages left to copy?
|
||||
bne .cp_page
|
||||
|
||||
} else {
|
||||
|
||||
.got_cp_len: tay ; Check the lo-byte of length.
|
||||
beq .cp_page
|
||||
|
||||
inx ; Increment # of pages to copy.
|
||||
|
||||
.get_cp_src: clc ; Calc address of partial page.
|
||||
adc <lzsa_srcptr + 0
|
||||
sta <lzsa_srcptr + 0
|
||||
bcs .get_cp_dst
|
||||
dec <lzsa_srcptr + 1
|
||||
|
||||
.get_cp_dst: tya
|
||||
clc ; Calc address of partial page.
|
||||
adc <lzsa_dstptr + 0
|
||||
sta <lzsa_dstptr + 0
|
||||
bcs .get_cp_idx
|
||||
dec <lzsa_dstptr + 1
|
||||
|
||||
.get_cp_idx: tya ; Negate the lo-byte of length.
|
||||
eor #$FF
|
||||
tay
|
||||
iny
|
||||
|
||||
.cp_page: lda (lzsa_srcptr),y
|
||||
sta (lzsa_dstptr),y
|
||||
iny
|
||||
bne .cp_page
|
||||
inc <lzsa_srcptr + 1
|
||||
inc <lzsa_dstptr + 1
|
||||
dex ; Any full pages left to copy?
|
||||
bne .cp_page
|
||||
|
||||
}
|
||||
|
||||
; ================================
|
||||
; xyz
|
||||
;
|
||||
; Copy bytes from decompressed window.
|
||||
;
|
||||
; N.B. X=0 is expected and guaranteed when we get here.
|
||||
;
|
||||
; xyz
|
||||
; ===========================
|
||||
; 00z 5-bit offset
|
||||
; 01z 9-bit offset
|
||||
; 10z 13-bit offset
|
||||
; 110 16-bit offset
|
||||
; 111 repeat offset
|
||||
;
|
||||
|
||||
.lz_offset: lda <lzsa_cmdbuf
|
||||
asl
|
||||
@ -304,48 +153,40 @@ lzsa2_unpack: ldy #0 ; Initialize source index.
|
||||
.get_5_bits: dex ; X=$FF
|
||||
.get_13_bits: asl
|
||||
php
|
||||
+LZSA_GET_NIBL ; Always returns with CS.
|
||||
jsr .get_nibble
|
||||
plp
|
||||
rol ; Shift into position, set C.
|
||||
eor #$01
|
||||
rol ; Shift into position, clr C.
|
||||
eor #$E1
|
||||
cpx #$00 ; X=$FF for a 5-bit offset.
|
||||
bne .set_offset
|
||||
sbc #2 ; Subtract 512 because 13-bit
|
||||
; offset starts at $FE00.
|
||||
bne .get_low8x ; Always NZ from previous SBC.
|
||||
sbc #2 ; 13-bit offset from $FE00.
|
||||
bne .set_hi_8 ; Always NZ from previous SBC.
|
||||
|
||||
.get_9_bits: dex ; X=$FF if CS, X=$FE if CC.
|
||||
asl
|
||||
bcc .get_low8
|
||||
bcc .get_lo_8
|
||||
dex
|
||||
bcs .get_low8 ; Always VS from previous BIT.
|
||||
bcs .get_lo_8 ; Always VS from previous BIT.
|
||||
|
||||
.get_13_16_rep: asl
|
||||
bcc .get_13_bits ; Shares code with 5-bit path.
|
||||
|
||||
.get_16_rep: bmi .lz_length ; Repeat previous offset.
|
||||
|
||||
;
|
||||
; Copy bytes from decompressed window.
|
||||
;
|
||||
; N.B. X=0 is expected and guaranteed when we get here.
|
||||
;
|
||||
.get_16_bits: jsr .get_byte ; Get hi-byte of offset.
|
||||
|
||||
.get_16_bits: jsr lzsa2_get_byte ; Get hi-byte of offset.
|
||||
.set_hi_8: tax
|
||||
|
||||
.get_low8x: tax
|
||||
.get_lo_8: !if LZSA_SMALL_SIZE {
|
||||
|
||||
.get_low8:
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) {
|
||||
|
||||
+LZSA_GET_SRC ; Get lo-byte of offset.
|
||||
jsr .get_byte ; Get lo-byte of offset.
|
||||
|
||||
} else {
|
||||
|
||||
lda (lzsa_srcptr),y
|
||||
lda (lzsa_srcptr),y ; Get lo-byte of offset.
|
||||
inc <lzsa_srcptr + 0
|
||||
beq .incsrc3
|
||||
.resume_src3:
|
||||
bne .set_offset
|
||||
inc <lzsa_srcptr + 1
|
||||
|
||||
}
|
||||
|
||||
@ -359,26 +200,24 @@ lzsa2_unpack: ldy #0 ; Initialize source index.
|
||||
clc
|
||||
adc #$02
|
||||
cmp #$09 ; Extended length?
|
||||
bne .got_lz_len
|
||||
bcc .got_lz_len
|
||||
|
||||
inx
|
||||
jsr .get_length ; X=1 table index for match.
|
||||
jsr .get_length ; X=0 for match, returns CC.
|
||||
|
||||
.got_lz_len: eor #$FF ; Negate the lo-byte of length
|
||||
tay ; and check for zero.
|
||||
iny
|
||||
beq .calc_lz_addr
|
||||
beq .get_lz_win
|
||||
eor #$FF
|
||||
|
||||
inx ; Increment # of pages to copy.
|
||||
|
||||
clc ; Calc destination for partial
|
||||
adc <lzsa_dstptr + 0 ; page.
|
||||
sta <lzsa_dstptr + 0
|
||||
bcs .calc_lz_addr
|
||||
.get_lz_dst: adc <lzsa_dstptr + 0 ; Calc address of partial page.
|
||||
sta <lzsa_dstptr + 0 ; Always CC from previous CMP.
|
||||
bcs .get_lz_win
|
||||
dec <lzsa_dstptr + 1
|
||||
|
||||
.calc_lz_addr: clc ; Calc address of match.
|
||||
.get_lz_win: clc ; Calc address of match.
|
||||
lda <lzsa_dstptr + 0 ; N.B. Offset is negative!
|
||||
adc <lzsa_offset + 0
|
||||
sta <lzsa_winptr + 0
|
||||
@ -397,56 +236,47 @@ lzsa2_unpack: ldy #0 ; Initialize source index.
|
||||
|
||||
jmp .cp_length ; Loop around to the beginning.
|
||||
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) = 0 {
|
||||
|
||||
.incsrc3:
|
||||
inc <lzsa_srcptr + 1
|
||||
bne .resume_src3 ; always taken
|
||||
|
||||
}
|
||||
|
||||
;
|
||||
; Lookup tables to differentiate literal and match lengths.
|
||||
;
|
||||
|
||||
.nibl_len_tbl: !byte 3 + $10 ; 0+3 (for literal).
|
||||
!byte 9 + $10 ; 2+7 (for match).
|
||||
.nibl_len_tbl: !byte 9 ; 2+7 (for match).
|
||||
!byte 3 ; 0+3 (for literal).
|
||||
|
||||
.byte_len_tbl: !byte 18 - 1 ; 0+3+15 - CS (for literal).
|
||||
!byte 24 - 1 ; 2+7+15 - CS (for match).
|
||||
.byte_len_tbl: !byte 24 - 1 ; 2+7+15 - CS (for match).
|
||||
!byte 18 - 1 ; 0+3+15 - CS (for literal).
|
||||
|
||||
;
|
||||
; Get 16-bit length in X:A register pair.
|
||||
; Get 16-bit length in X:A register pair, return with CC.
|
||||
;
|
||||
|
||||
.get_length: +LZSA_GET_NIBL
|
||||
cmp #$FF ; Extended length?
|
||||
.get_length: jsr .get_nibble
|
||||
cmp #$0F ; Extended length?
|
||||
bcs .byte_length
|
||||
adc .nibl_len_tbl,x ; Always CC from previous CMP.
|
||||
|
||||
.got_length: ldx #$00 ; Set hi-byte of 4 & 8 bit
|
||||
rts ; lengths.
|
||||
|
||||
.byte_length: jsr lzsa2_get_byte ; So rare, this can be slow!
|
||||
.byte_length: jsr .get_byte ; So rare, this can be slow!
|
||||
adc .byte_len_tbl,x ; Always CS from previous CMP.
|
||||
bcc .got_length
|
||||
beq .finished
|
||||
|
||||
.word_length: jsr lzsa2_get_byte ; So rare, this can be slow!
|
||||
.word_length: jsr .get_byte ; So rare, this can be slow!
|
||||
pha
|
||||
jsr lzsa2_get_byte ; So rare, this can be slow!
|
||||
jsr .get_byte ; So rare, this can be slow!
|
||||
tax
|
||||
pla
|
||||
clc ; MUST return CC!
|
||||
rts
|
||||
|
||||
lzsa2_get_byte:
|
||||
lda (lzsa_srcptr),y ; Subroutine version for when
|
||||
.get_byte: lda (lzsa_srcptr),y ; Subroutine version for when
|
||||
inc <lzsa_srcptr + 0 ; inlining isn't advantageous.
|
||||
beq lzsa2_next_page
|
||||
beq .next_page
|
||||
rts
|
||||
|
||||
lzsa2_next_page:
|
||||
inc <lzsa_srcptr + 1 ; Inc & test for bank overflow.
|
||||
.next_page: inc <lzsa_srcptr + 1
|
||||
rts
|
||||
|
||||
.finished: pla ; Decompression completed, pop
|
||||
@ -457,66 +287,29 @@ lzsa2_next_page:
|
||||
; Get a nibble value from compressed data in A.
|
||||
;
|
||||
|
||||
!if (LZSA_SLOW_NIBL | LZSA_SMALL_SIZE) {
|
||||
|
||||
lzsa2_get_nibble:
|
||||
lsr <lzsa_nibflg ; Is there a nibble waiting?
|
||||
.get_nibble: lsr <lzsa_nibflg ; Is there a nibble waiting?
|
||||
lda <lzsa_nibble ; Extract the lo-nibble.
|
||||
bcs .got_nibble
|
||||
|
||||
inc <lzsa_nibflg ; Reset the flag.
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) {
|
||||
|
||||
+LZSA_GET_SRC
|
||||
!if LZSA_SMALL_SIZE {
|
||||
jsr .get_byte
|
||||
|
||||
} else {
|
||||
|
||||
lda (lzsa_srcptr),y
|
||||
inc <lzsa_srcptr + 0
|
||||
beq .incsrc4
|
||||
.resume_src4:
|
||||
|
||||
}
|
||||
|
||||
sta <lzsa_nibble ; Preserve for next time.
|
||||
lsr ; Extract the hi-nibble.
|
||||
lsr
|
||||
lsr
|
||||
lsr
|
||||
|
||||
.got_nibble: ora #$F0
|
||||
rts
|
||||
|
||||
} else {
|
||||
|
||||
lzsa2_new_nibble:
|
||||
inc <lzsa_nibflg ; Reset the flag.
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) {
|
||||
|
||||
+LZSA_GET_SRC
|
||||
|
||||
} else {
|
||||
|
||||
lda (lzsa_srcptr),y
|
||||
inc <lzsa_srcptr + 0
|
||||
beq .incsrc4
|
||||
.resume_src4:
|
||||
|
||||
}
|
||||
|
||||
sta <lzsa_nibble ; Preserve for next time.
|
||||
lsr ; Extract the hi-nibble.
|
||||
lsr
|
||||
lsr
|
||||
lsr
|
||||
rts
|
||||
|
||||
}
|
||||
|
||||
!if (LZSA_NO_INLINE | LZSA_USE_FFFF) = 0 {
|
||||
|
||||
.incsrc4:
|
||||
bne .set_nibble
|
||||
inc <lzsa_srcptr + 1
|
||||
bne .resume_src4 ; always taken
|
||||
|
||||
}
|
||||
|
||||
.set_nibble: sta <lzsa_nibble ; Preserve for next time.
|
||||
lsr ; Extract the hi-nibble.
|
||||
lsr
|
||||
lsr
|
||||
lsr
|
||||
|
||||
.got_nibble: and #$0F
|
||||
rts
|
||||
|
||||
Loading…
Reference in New Issue
Block a user