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Optimize Text to HGR address by Mike B to save 1 byte

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Michaelangel007 2017-07-24 11:42:17 -07:00
parent 629866d97f
commit 5122a0aaf9
3 changed files with 3 additions and 4 deletions
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linuxlogo
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linuxlogo.s
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@ -309,10 +309,9 @@ MakeShiftMask
lda zTxtPtr+0 ; every 8 HGR scanline address
sta zHgrPtr+0 ; is exactly same as Text low byte
lda zTxtPtr+1
clc ; every 8 HGR scanline address
adc #$1c ; is Text Page $04 + $1C = HGR Page $20
sta zHgrPtr+1
lda zTxtPtr+1 ; every 8 HGR scanline address
eor #$24 ; is Text Page $04 + $1C = HGR Page $20; CLC, ADC #$1C
sta zHgrPtr+1 ; but we can optimize for HGR page 1 via EOR #$24 -- Thanks Mike B.!
; ------------------------------------------------------------------------
; Copy unpacked buffer to 8 HGR scanlines

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