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@ -1,12 +1,4 @@
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HGRCalc
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; in: A = HGR row (0x00..0xBF)
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; out: A/X clobbered
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; Y preserved
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; ($26) points to first byte of given HGR row on hi-res page 1
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; ($3C) points to same byte on hi-res page 2
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; based on 'Woz Recodes Hi-Res Address Calculations'
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; Apple Assembly Line vol. 7 issue 3 (December 1986)
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; http://www.txbobsc.com/aal/1986/aal8612.html#a9
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!macro HGR_CALC {
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asl
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tax
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and #$F0
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@ -27,6 +19,18 @@ HGRCalc
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sta $3d
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lda $26
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sta $3c
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}
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HGRCalc
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; in: A = HGR row (0x00..0xBF)
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; out: A/X clobbered
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; Y preserved
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; ($26) points to first byte of given HGR row on hi-res page 1
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; ($3C) points to same byte on hi-res page 2
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; based on 'Woz Recodes Hi-Res Address Calculations'
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; Apple Assembly Line vol. 7 issue 3 (December 1986)
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; http://www.txbobsc.com/aal/1986/aal8612.html#a9
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+HGR_CALC
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rts
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HGRBlockCopy
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@ -35,11 +39,12 @@ HGRBlockCopy
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; out: Y preserved
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; X = #$00
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; Z set
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; C clear
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; all other flags and registers clobbered
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asl
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asl
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asl
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jsr HGRCalc
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+HGR_CALC
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clc
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ldx #$08
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@loop
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@ -60,11 +65,12 @@ HGRBlockToWhite
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; out: Y preserved
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; X = #$00
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; Z set
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; C clear
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; all other flags and registers clobbered
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asl
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asl
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asl
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jsr HGRCalc
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+HGR_CALC
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clc
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ldx #$08
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@loop
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