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Nibble Volume 09, No. 12 (1988-12)(MicroSPARC)(Side A)[a].zip
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Nibble Volume 09, No. 12 (1988-12)(MicroSPARC)(Side A)[a].po
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PIC.CREATE.S
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1996-12-24
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68 lines
*
* PIC.CREATE
* By Peter Stubbs
* Copyright(c) 1988
* MicroSPARC, Inc.
* Concord, MA 01742
*
* Merlin 16
*
TR ADR
XC
XC
ORG $300
VIDSAVE EQU $9
PIC EQU $E12000 ;Start of Super res screen
SCB EQU $E19D00 ;Start of SCB's
PALZERO EQU $E19E00 ;Location of palette $0
NEWVIDEO EQU $C029 ;Super Res/linear softswitch
SEC ;EMULATION MODE ON
XCE
MX %11
LDA NEWVIDEO
STA VIDSAVE ;Save for later
ORA #%01000000 ;Turn on linear addressing
STA NEWVIDEO
* set up the SCB's to all point at palette zero
LDX #$00
TXA
LOOP1 STAL SCB,x
INX
CPX #$C8
BEQ MAKE_PAL
BRA LOOP1
MAKE_PAL CLC ;Native mode on
XCE
MX %00
REP #$30
* Create a palette of the 15 intensities of pink
LDA #$0000
TAX
LOOP2 STAL PALZERO,X
CLC
ADC #$0101 ;Increase intensity by 1
INX
INX
CPX #$0020
BNE LOOP2
* Create a "picture" of shaded columns
LDA #$0000
TAX
LOOP STAL PIC,X
INX
INX
CLC
ADC #$1111
BCC SKIP
LDA #$0000
SKIP CPX #$7D00
BNE LOOP
SEC ;back to emulation mode
XCE
LDA VIDSAVE ;Restore original value
STA NEWVIDEO
RTS
END CHK ;MERLIN chk = 14