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https://github.com/deater/dos33fsprogs.git
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91 lines
1.7 KiB
ArmAsm
91 lines
1.7 KiB
ArmAsm
;======================
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; load large RLE image
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;======================
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; Output is A:00 (assume page aligned)
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; Input is in GBASH/GBASL
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; format: first byte=xsize
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; A0,X,Y means run of X bytes of Y color
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; A1 means end of file
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; A2-AF,X means run of low nibble, X color
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; if high nibble not A: just display color
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; CV = current Y
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; CH = max X xsize (usually 40)
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; TEMP = page
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; TEMPY= current X
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load_rle_large:
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sta OUTH
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ldy #0
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sty OUTL
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sty CV ; init Y to 0
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jsr load_and_increment ; load xsize, increment
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sta CH
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rle_large_loop:
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jsr load_and_increment ; load next value from
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tax
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cmp #$A1 ; if 0xa1
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beq rle_large_done ; we are done
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and #$f0 ; mask
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cmp #$a0 ; see if special AX
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beq rle_large_decompress_special
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; not special, just color
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txa ; put color back in A
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ldx #$1 ; only want to print 1
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bne rle_large_decompress_run
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rle_large_decompress_special:
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txa ; put read value back in A
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and #$0f ; check if was A0
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bne rle_large_decompress_color ; if A0 need to read run, color
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rle_large_decompress_large:
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jsr load_and_increment ; run length now in A
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rle_large_decompress_color:
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tax ; put runlen into X
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jsr load_and_increment ; get color into A
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rle_large_decompress_run:
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rle_large_run_loop:
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sta (OUTL),y ; write out the value
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inc OUTL
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bne rle_large_inc_done
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inc OUTH ; handle 16-bit
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rle_large_inc_done:
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dec TEMPY
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bne rle_large_not_eol ; if less then keep going
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rle_large_not_eol:
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dex
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bne rle_large_run_loop ; if not zero, keep looping
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beq rle_large_loop ; and branch always
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rle_large_done:
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lda #$15 ; move the cursor somewhere sane
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sta CV
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rts
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;load_and_increment:
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; lda (GBASL),Y
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; inc GBASL
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; bne lai_no_oflo
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; inc GBASH
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;lai_no_oflo:
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; rts
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