JSR Brtt INC Ercnt UP to FF

0985	872B	20	C1	87		JSR BRTT	;INC ERCNT (UP TO FF)
0986	872E	20	B2	82	F3	JSR INCCMP
0987	8731	70	7C			BVS B1
0988	8733	F0	EE			BEQ F1
0989	8735	90	EC			BCC F1
0990	8737	B0	76		F2	BCS B1	;(ALWAYS)
0991	8739	C9	42		BLK3	CMP #'B'	;BLOCK MOVE (OVERLAP OKAY)
0992	873B	F0	03			BEQ *+5
0993	873D	4C	CD 87			JMP S13B
0994	8740	A9	00			LDA #0
0995	8742	8D	52	A6		STA ERCNT
0996	8745	20	9C	82		JSR P2SCR
0997	8748	AD 4E A6				LDA P1L
0998	874B	85	FC			STA $FC
0999	874D	AD 4F A6				LDA P1H
1000	8750	85	FD			STA $FD
1001	8752	C5	FF			CMP $FF	;WHICH DIRECTION TO MOVE?
1002	8754	D0	06			BNE *+8
1003	8756	A5	FC			LDA $FC
1004	8758	C5	FE			CMP $FE
1005	875A	F0	53			BEQ B1	;16 BITS EQUAL THEN FINISHED
1006	875C	B0	14			BCS B2	;MOVE DEC'NG
1007	875E	20	B7	87	BLP	JSR BMOVE	;MOVE INC'NG
1008	8761	E6	FC			INC $FC
1009	8763	D0	02			BNE *+4
1010	8765	E6	FD			INC $FD
1011	8767	20	B2	82		JSR INCCMP
1012	876A	70	43			BVS B1
1013	876C	F0	F0			BEQ BLP
1014	876E	90	EE			BCC BLP
1015	8770	B0	3D			BCS B1
1016	8772	A5	FC		B2	LDA $FC	;CALC VALS FOR MOVE DEC'NG
1017	8774	18				CLC
1018	8775	6D	4A	A6		ADC P3L
1019	8778	85	FC			STA $FC
1020	877A	A5	FD			LDA $FD
1021	877C	6D	4B	A6		ADC P3H
1022	877F	85	FD			STA $FD
1023	8781	38				SEC
1024	8782	A5	FC			LDA $FC
1025	8784	E5	FE			SBC $FE
1026	8786	85	FC			STA $FC
1027	8788	A5	FD			LDA $FD
1028	878A	E5	FF			SBC $FF
1029	878C	85	FD			STA $FD
1030	878E	20	A7	82		JSR P3SCR
1031	8791	AD 4C A6				LDA P2L
1032	8794	8D	4A	A6		STA P3L
1033	8797	AD 4D A6				LDA P2H
1034	879A	8D	4B	A6		STA P3H
1035	879D	20	B7	87	BLP1	JSR BMOVE	;MOVE DEC'NG
1036	87A0	A5	FC			LDA $FC
1037	87A2	D0	02			BNE *+4
1038	87A4	C6	FD			DEC $FD
1039	87A6	C6	FC			DEC $FC
1040	87A8	20	BE 82			JSR DECCMP
1041	87AB 70 02					BVS B1
1042	87AD B0 EE					BCS BLP1
1043	87AF AD 52 A6				B1	LDA ERCNT	;FINISHED, TEST ERCNT
1044	87B2	38				SEC
1045	87B3	D0	01			BNE *+3
1046	87B5	18				CLC

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.

JSR BRTT

;INC ERCNT (UP TO FF)

II specifications