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Faster SHR scrolling (thanks Kent Dickey :) )

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Bobbi Webber-Manners 2022-12-26 20:41:10 -05:00
parent bd4da7bbdd
commit 986d8aa1fc
3 changed files with 69 additions and 41 deletions
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BIN
applecorn.po
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2
auxmem.init.s
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@ -218,6 +218,6 @@ BYTE00 BEQ BYTE00A ; OSBYTE 0,0 - generate error
RTS ; %000x1xxx host type, 'A'pple
BYTE00A BRK
DB $F7
HELLO ASC 'Applecorn MOS 2022-12-26-HOHOHO'
HELLO ASC 'Applecorn MOS 2022-12-26'
DB $00 ; Unify MOS messages

108
auxmem.shr.s
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@ -330,47 +330,75 @@ SHRNEXTROW LDA VDUADDR+0 ; Add 160 to VDUADDR
* Forwards scroll one line
* Copy text line A+1 to line A
* Note: Code for this courtesy Kent Dickey
* TODO: This is only for 640 mode at present
SHRSCR1LINE TAY
LDA SHRTAB,Y ; MSB of address of line A
STA VDUADDR+1
STZ VDUADDR+0 ; Addr of start of line
INY
LDA SHRTAB,Y ; MSB of address of line A+1
STA VDUADDR2+1
STZ VDUADDR2+0 ; Addr of start of line
LDA #$E1 ; Bank $E1
STA VDUBANK
STA VDUBANK2
LDA #$08 ; Eight rows of pixels
STA :CTR
INC TXTWINRGT
:L0 LDA TXTWINLFT
TAX
ASL ; 2 bytes / char
TAY
:L1 CPX TXTWINRGT
BCS :S1
LDA [VDUADDR2],Y
STA [VDUADDR],Y
INY
LDA [VDUADDR2],Y
STA [VDUADDR],Y
INY
INX
BRA :L1
:S1 JSR SHRNEXTROW ; Add 160 to VDUADDR
LDA VDUADDR2+0 ; Add 160 to VDUADDR2
CLC
ADC #160
STA VDUADDR2+0
LDA VDUADDR2+1
ADC #$00
STA VDUADDR2+1
DEC :CTR
BNE :L0
DEC TXTWINRGT
RTS
SHRSCR1LINE
; acc=line to scroll (0-24)
; nead to calc acc * $500. Could use a table, but this is about as fast
phy
phx
sta VDUADDR+1
stz VDUADDR
php
sei
clc
xce
phb
rep #$31 ; M,X 16 bit, carry clear
MX %00 ; Tell Merlin
lda VDUADDR
asl
asl
adc VDUADDR
sta VDUADDR ;; VDUADDR = line * $500
lda TXTWINLFT
asl
and #$00ff
adc VDUADDR
sta VDUADDR ; VDUADDR = Minimum position
sep #$21 ; M 8 bit, X 16 bit, carry set
MX %10 ; Tell Merlin
lda TXTWINRGT
sbc TXTWINLFT
rep #$31 ; M,X 16 bit, carry clear
MX %00 ; Tell Merlin
asl
and #$00ff
adc VDUADDR
tax
pea #$e1e1
plb
plb
:loop1
lda $2500,x ;; 2 bytes, row 0
sta $2000,x
lda $25a0,x ; row 1
sta $20a0,x
lda $2640,x ; row 2
sta $2140,x
lda $26e0,x ; row 3
sta $21e0,x
lda $2780,x ; row 4
sta $2280,x
lda $2820,x ; row 5
sta $2320,x
lda $28c0,x ; row 6
sta $23c0,x
lda $2960,x ; row 7
sta $2460,x
dex
dex
bmi :done
cpx VDUADDR
bcs :loop1
:done
plb
sec
xce
plp
plx
ply
rts
* Reverse scroll one line