diff --git a/demos/vertical_scroll2/decompress_fast_v2.s b/demos/vertical_scroll2/decompress_fast_v2.s new file mode 100644 index 00000000..fb2f24ad --- /dev/null +++ b/demos/vertical_scroll2/decompress_fast_v2.s @@ -0,0 +1,370 @@ +; note -- modified by Vince Weaver to assemble with ca65 +; in this case, A = page to decompress to +; getsrc_smc+1, getsrc_smc+2 is src location + +; ----------------------------------------------------------------------------- +; Decompress raw LZSA2 block. +; Create one with lzsa -r -f2 +; +; in: +; * LZSA_SRC_LO and LZSA_SRC_HI contain the compressed raw block address +; * LZSA_DST_LO and LZSA_DST_HI contain the destination buffer address +; +; out: +; * LZSA_DST_LO and LZSA_DST_HI contain the last decompressed byte address, +1 +; +; ----------------------------------------------------------------------------- +; Backward decompression is also supported, use lzsa -r -b -f2 +; To use it, also define BACKWARD_DECOMPRESS=1 before including this code! +; +; in: +; * LZSA_SRC_LO/LZSA_SRC_HI must contain the address of the last byte of compressed data +; * LZSA_DST_LO/LZSA_DST_HI must contain the address of the last byte of the destination buffer +; +; out: +; * LZSA_DST_LO/LZSA_DST_HI contain the last decompressed byte address, -1 +; +; ----------------------------------------------------------------------------- +; +; Copyright (C) 2019 Emmanuel Marty, Peter Ferrie +; +; 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. +; ----------------------------------------------------------------------------- + +;NIBCOUNT = $FC ; zero-page location for temp offset + +decompress_lzsa2_fast: + + sta LZSA_DST_HI + + ldy #$00 + sty LZSA_DST_LO + sty NIBCOUNT + +decode_token: + jsr getsrc ; read token byte: XYZ|LL|MMM + pha ; preserve token on stack + + and #$18 ; isolate literals count (LL) + beq no_literals ; skip if no literals to copy + cmp #$18 ; 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 #$12 ; LITERALS_RUN_LEN_V2 + 15 ? + bcc prepare_copy_literals_direct ; if less, literals count is complete + + jsr getsrc ; get extra byte of variable literals count + ; the carry is always set by the CMP above + ; GETSRC doesn't change it + sbc #$EE ; overflow? + jmp prepare_copy_literals_direct + +prepare_copy_literals_large: + ; 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 ; (*same as JMP PREPARE_COPY_LITERALS_HIGH but shorter) + +prepare_copy_literals: + lsr ; shift literals count into place + lsr + lsr + +prepare_copy_literals_direct: + tax + bcs prepare_copy_literals_large ; if so, literals count is large + +prepare_copy_literals_high: + txa + beq copy_literals + iny + +copy_literals: + jsr getput ; copy one byte of literals + dex + bne copy_literals + dey + bne copy_literals + +no_literals: + pla ; retrieve token from stack + pha ; preserve token again + asl + bcs repmatch_or_large_offset ; 1YZ: rep-match or 13/16 bit offset + + asl ; 0YZ: 5 or 9 bit offset + bcs offset_9_bit + + ; 00Z: 5 bit offset + + ldx #$FF ; set offset bits 15-8 to 1 + + jsr getcombinedbits ; rotate Z bit into bit 0, read nibble for bits 4-1 + ora #$E0 ; set bits 7-5 to 1 + bne got_offset_lo ; go store low byte of match offset and prepare match + +offset_9_bit: ; 01Z: 9 bit offset + ;;asl ; shift Z (offset bit 8) in place + rol + rol + and #$01 + eor #$FF ; set offset bits 15-9 to 1 + bne got_offset_hi ; go store high byte, read low byte of match offset and prepare match + ; (*same as JMP GOT_OFFSET_HI but shorter) + +repmatch_or_large_offset: + asl ; 13 bit offset? + bcs repmatch_or_16bit ; handle rep-match or 16-bit offset if not + + ; 10Z: 13 bit offset + + jsr getcombinedbits ; rotate Z bit into bit 8, read nibble for bits 12-9 + adc #$DE ; set bits 15-13 to 1 and substract 2 (to substract 512) + bne got_offset_hi ; go store high byte, read low byte of match offset and prepare match + ; (*same as JMP GOT_OFFSET_HI but shorter) + +repmatch_or_16bit: ; rep-match or 16 bit offset + ;;ASL ; XYZ=111? + bmi rep_match ; reuse previous offset if so (rep-match) + + ; 110: handle 16 bit offset + jsr getsrc ; grab high 8 bits +got_offset_hi: + tax + jsr getsrc ; grab low 8 bits +got_offset_lo: + sta OFFSLO ; store low byte of match offset + stx OFFSHI ; store high byte of match offset + +rep_match: +.ifdef BACKWARD_DECOMPRESS + + ; Backward decompression - substract match offset + + sec ; add dest + match offset + lda putdst+1 ; low 8 bits +OFFSLO = *+1 + sbc #$AA + sta copy_match_loop+1 ; store back reference address + lda putdst+2 +OFFSHI = *+1 + sbc #$AA ; high 8 bits + sta copy_match_loop+2 ; store high 8 bits of address + sec + +.else + + ; Forward decompression - add match offset + + clc ; add dest + match offset + lda putdst+1 ; low 8 bits +OFFSLO = *+1 + adc #$AA + sta copy_match_loop+1 ; store back reference address +OFFSHI = *+1 + lda #$AA ; high 8 bits + adc putdst+2 + sta copy_match_loop+2 ; store high 8 bits of address +.endif + + pla ; retrieve token from stack again + 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? + 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 #$18 ; MIN_MATCH_SIZE_V2 + MATCH_RUN_LEN_V2 + 15? + bcc prepare_copy_match ; if less, match length is complete + + jsr getsrc ; get extra byte of variable match length + ; the carry is always set by the CMP above + ; GETSRC doesn't change it + sbc #$E8 ; overflow? + +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 + +prepare_copy_match_y: + txa + beq copy_match_loop + iny + +copy_match_loop: + lda $AAAA ; get one byte of backreference + jsr putdst ; copy to destination + +.ifdef BACKWARD_DECOMPRESS + + ; Backward decompression -- put backreference bytes backward + + lda copy_match_loop+1 + beq getmatch_adj_hi +getmatch_done: + dec copy_match_loop+1 + +.else + + ; Forward decompression -- put backreference bytes forward + + inc copy_match_loop+1 + beq getmatch_adj_hi +getmatch_done: + +.endif + + dex + bne copy_match_loop + dey + bne copy_match_loop + jmp decode_token + +.ifdef BACKWARD_DECOMPRESS + +getmatch_adj_hi: + dec copy_match_loop+2 + jmp getmatch_done + +.else + +getmatch_adj_hi: + inc copy_match_loop+2 + jmp getmatch_done +.endif + +getcombinedbits: + eor #$80 + asl + php + + jsr getnibble ; get nibble into bits 0-3 (for offset bits 1-4) + plp ; merge Z bit as the carry bit (for offset bit 0) +combinedbitz: + rol ; nibble -> bits 1-4; carry(!Z bit) -> bit 0 ; carry cleared +decompression_done: + rts + +getnibble: +NIBBLES = *+1 + lda #$AA + lsr NIBCOUNT + bcc need_nibbles + and #$0F ; isolate low 4 bits of nibble + rts + +need_nibbles: + inc NIBCOUNT + jsr getsrc ; get 2 nibbles + sta NIBBLES + lsr + lsr + lsr + lsr + sec + rts + +.ifdef BACKWARD_DECOMPRESS + + ; Backward decompression -- get and put bytes backward + +getput: + jsr getsrc +putdst: +LZSA_DST_LO = *+1 +LZSA_DST_HI = *+2 + sta $AAAA + lda putdst+1 + beq putdst_adj_hi + dec putdst+1 + rts + +putdst_adj_hi: + dec putdst+2 + dec putdst+1 + rts + +getlargesrc: + jsr getsrc ; grab low 8 bits + tax ; move to X + ; fall through grab high 8 bits + +getsrc: +LZSA_SRC_LO = *+1 +LZSA_SRC_HI = *+2 + lda $AAAA + pha + lda getsrc+1 + beq getsrc_adj_hi + dec getsrc+1 + pla + rts + +getsrc_adj_hi: + dec getsrc+2 + dec getsrc+1 + pla + rts + +.else + + ; Forward decompression -- get and put bytes forward + +getput: + jsr getsrc +putdst: +LZSA_DST_LO = *+1 +LZSA_DST_HI = *+2 + sta $AAAA + inc putdst+1 + beq putdst_adj_hi + rts + +putdst_adj_hi: + inc putdst+2 + rts + +getlargesrc: + jsr getsrc ; grab low 8 bits + tax ; move to X + ; fall through grab high 8 bits + +getsrc: +getsrc_smc: +LZSA_SRC_LO = *+1 +LZSA_SRC_HI = *+2 + lda $AAAA + inc getsrc+1 + beq getsrc_adj_hi + rts + +getsrc_adj_hi: + inc getsrc+2 + rts +.endif + diff --git a/demos/vertical_scroll2/hello.bas b/demos/vertical_scroll2/hello.bas new file mode 100644 index 00000000..f3fccafd --- /dev/null +++ b/demos/vertical_scroll2/hello.bas @@ -0,0 +1,4 @@ +5 HOME +10 PRINT "GR VERTICAL SCROLLER" +' 20 PRINT CHR$(4)+"BRUN SCROLLER" +20 PRINT CHR$(4)"CATALOG"