BIT Imask See if DOT is SET | Apple II instruction

2523	F0F0 20		58	EB		JSR	LDAY
2524	F0F3 2C		7C	A4		BIT	IMASK	;SEE IF DOT IS SET
2525	F0F6 F0		16			BEQ	IPS2	;NO SO GO ON TO NEXT CHAR
2526	F0F8 AD		7A	A4		LDA	IBITL	;DOT ON SO SET THE CURR SOLENOID
2527	F0FB F0		08			BEQ	IPS3	;LSB OF SOL MASK IS 0 , DO MSB
2528	F0FD 0D		78	A4		ORA	IOUTL	;SET THE SOLENOID IN THE PATTERN
2529	F100	8D	78	A4		STA	IOUTL
2530	F103	D0	09			BNE	IPS2	;BRANCH ALWAYS
2531	F105	AD	7B	A4	IPS3	LDA	IBITU	;SOLENOID IS ONE OF THE 2 MSD
2532	F108	0D	79	A4		ORA	IOUTU	;SET THE BIT IN THE PATTERN
2533	F10B 8D		79	A4		STA	IOUTU
2534	F10E 0E		7A	A4	IPS2	ASL	IBITL	;SHIFT MSK TO NXT CHR POSITION
2535	F111	2E	7B	A4		ROL	IBITU
2536	F114	CA				DEX		;DECR PTR INTO BUFFER
2537	F115	CA				DEX
2538	F116	10	D0			BPL IPS1		;NOT END YET
2539	F118				;SOLENOID PATTERN IS SET UP IN IOUTU,IOUTL
2540	F118	AD	79	A4		LDA IOUTU		;LEFTMOST 2
2541	F11B 29		03			AND #$03		;DISABLE FOR SEGMENTS
2542	F11D 8D		79	A4		STA	IOUTU
2543	F120	60				RTS
2544	F121
2545	F121				; SUBROUTINE INCP
2546	F121				;THIS SUBROUTINE IS USED TO UPDATE THE PRINTER VARIABLES
2547	F121				;TO POINT TO THE NEXT DOT POSITION TO BE PRINTED
2548	F121				;X REG IS USED TO POINT TO THE VARIABLE BLOCK OF
2549	F121				;BEING UPDATED
2550	F121				;ON EXIT X		CONTAINS THE POINTER TO THE LAST CHARACTER IN
2551	F121				;THE PRINT		BUFFER
2552	F121				;CONTENTS OF A,Y ON EXIT ARE ARBITRARY
2553	F121	BD	74	A4	INCP	LDA IDIR,X		;EXAMINE DIRECTION(+ OR -)
2554	F124	10	1E			BPL OP03		;DIRECTION = +
2555	F126				;*DIRECTION = -
2556	F126	BD	75	A4		LDA ICOL,X		;SEE WHAT THE COLUMN IS
2557	F129	F0	05			BEQ OP04		;COLUMN = 0 SO END OF DIGIT
2558	F12B				;**COLUMN # 0 SO JUST DECREMENT COLUMN
2559	F12B DE		75	A4		DEC	ICOL,X
2560	F12E 10		33			BPL	NEWCOL	;BRANCH ALWAYS
2561	F130				;**COLUMN = 0 SO SEE IF EVEN OR ODD DIGIT
2562	F130	BD	76	A4	OP04	LDA	IOFFST,X
2563	F133	F0	0A			BEQ	OP07	;OFFSET = 0 SO DIRECTION CHANGE
2564	F135				;***OFFSET		= 1 SO MOVE	TO RIGHT DIGIT
2565	F135	DE	76	A4		DEC	IOFFST,X	;OFFSET <= 0 (LEFT CHARACTER)
2566	F138	A9	04			LDA	#4	;COLUMN <= 4
2567	F13A 9D		75	A4		STA	ICOL,X
2568	F13D 10		24			BPL	NEWCOL	;BRANCH ALWAYS
2569	F13F				;***OFFSET		= 0 SO CHANGE DIRECTION TO +
2570	F13F FE		74	A4	OP07	INC	IDIR,X	;DIRECTION <= $00 (+)
2571	F142	10	1C			BPL	NEWROW	;BRANCH ALWAYS
2572	F144				;*DIRECTION = +
2573	F144	BD	75	A4	OP03	LDA ICOL,X		;SEE IF LAST COLUMN IN DIGIT
2574	F147	C9	04			CMP	#4
2575	F149	F0	05			BEQ	OP05	;COLUMN = 4 SO GO TO NEXT DIGIT
2576	F14B FE		75	A4		INC	ICOL,X	;JUST INCR COLUMN-NOT END OF DIGIT
2577	F14E 10		13			BPL NEWCOL		;BRANCH ALWAYS
2578	F150				;**AT COLUMN 4 -- SEE IF LEFT OR RIGHT DIGIT
2579	F150	BD	76	A4	OP05	LDA	IOFFST,X
2580	F153	D0	08			BNE	OP06	;OFFSET # 0 SO RIGHT DIGIT
2581	F155	9D	75	A4		STA	ICOL,X	;COLUMN <= 0
2582	F158	FE	76	A4		INC	IOFFST,X	;OFFSET <= 1 (RIGHT CHARACTER)
2583	F15B 10		06			BPL	NEWCOL	;BRANCH ALWAYS
2584	F15D				;***OFFSET		= 1 SO DIRECTION CHANGE

II specifications

The Apple II, launched in April 1977, was one of the first highly successful mass-produced microcomputer products. It marked a significant leap in personal computing, setting standards for future developments in the industry. Created by Steve Wozniak and Steve Jobs, the Apple II differentiated itself with its user-friendly design, appealing aesthetics, and robust capabilities.

One of the standout features of the Apple II was its open architecture, which allowed users to expand and enhance the computer's functionality. This design enabled hundreds of third-party hardware and software developers to contribute to its ecosystem, resulting in an array of peripherals, including printers, modems, and storage devices. The Apple II utilized a MOS Technology 6502 microprocessor running at a clock speed of 1 MHz. Initially equipped with 4 KB of RAM, the machine could be expanded to 48 KB, accommodating more complex applications and programs.

The Apple II was also notable for its colorful graphics. It was one of the first computers to support color display, offering a 6-color palette with a resolution of 280x192 pixels in 16 colors when using its Color Graphics Card. This feature significantly enhanced the visual appeal of games and educational software developed for the platform, making computing more accessible and entertaining for various audiences.

Apple's commitment to user experience was evident in the design of the machine. It featured an integrated keyboard and a plastic case, which was both durable and visually appealing. The self-contained design included drive bays for floppy disk drives, allowing for quicker data access than traditional tape drives. It also supported audio output, enabling sound effects and music, a novelty at the time.

The introduction of the Apple DOS operating system further underscored the machine's capabilities. DOS streamlined file management and made it easier for users to navigate and manage their data. The combination of hardware and software positioned the Apple II as an educational tool and a gaming platform, fostering a vibrant software ecosystem.

The Apple II family continued to evolve, with variations like the Apple II+, IIe, and IIgs being introduced over the years. These iterations brought enhancements in memory, processing power, and graphics capabilities. The legacy of the Apple II endures, not only as a foundational product in personal computing but also as a symbol of innovation that paved the way for future advancements in technology. Its impact is still felt today, as it inspired countless developers and shaped the trajectory of the computer industry.

BIT

IMASK

;SEE IF DOT IS SET

ORA

ORA

CMP

II specifications