64 lines
1.3 KiB
ArmAsm
64 lines
1.3 KiB
ArmAsm
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FATFONT = $6000
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; A = character, X = column, Y = row; A is clobbered, X&Y are not
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stx SCRATCH_X
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sty SCRATCH_Y
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; find address of glyph
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sta font_ptr
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lda #0
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sta font_ptr + 1
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asl font_ptr ; multiply by 8
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rol font_ptr + 1
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asl font_ptr
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rol font_ptr + 1
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asl font_ptr
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rol font_ptr + 1
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clc ; add font table address to get pointer inside font table
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lda #<fatfont ; would be slightly faster if page aligned because you
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adc font_ptr ; could just store the low byte
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sta font_ptr
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lda #>fatfont
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adc font_ptr+1
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sta font_ptr+1
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lda hgrtextrow_l,y ; load address of first line of hgr text
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sta hgr_ptr
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lda hgrtextrow_h,y
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sta hgr_ptr+1
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ldx #0
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slowfont_loop
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txa
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tay
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lda (font_ptr),y
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ldy SCRATCH_X ; col goes in y
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sta (hgr_ptr),y
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clc
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lda #4
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adc hgr_ptr+1
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sta hgr_ptr+1
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inx
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cpx #8
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bcc slowfont_loop
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done
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ldx SCRATCH_X
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ldy SCRATCH_Y
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rts
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hgrtextrow_l
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.byte $00,$80,$00,$80,$00,$80,$00,$80
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.byte $28,$A8,$28,$A8,$28,$A8,$28,$A8
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.byte $50,$D0,$50,$D0,$50,$D0,$50,$D0
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hgrtextrow_h
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.byte $20,$20,$21,$21,$22,$22,$23,$23
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.byte $20,$20,$21,$21,$22,$22,$23,$23
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.byte $20,$20,$21,$21,$22,$22,$23,$23
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