SBC P3L | Apple II manual

1109	8835	6D	4C	A6		ADC	P2L
1110	8838	A8				TAY
1111	8839	AD 4F A6				LDA	P1H
1112	883C	6D	4D	A6		ADC	P2H
1113	883F	AA				TAX
1114	8840	38				SEC
1115	8841	98				TYA
1116	8842	ED 4A A6				SBC	P3L
1117	8845	A8				TAY
1118	8846	8A				TXA
1119	8847	ED 4B A6				SBC	P3H
1120	884A	AA				TAX
1121	884B	98				TYA
1122	884C	20	F4	82		JSR	OUTXAH
1123	884F	18				CLC
1124	8850	60				RTS
1125	8851	C9	45		EXE3	CMP #'E'		;EXECUTE FROM RAM, 1-3 PARMS
1126	8853	D0	57			BNE	E3PARM
1127	8855				; SEE IF VECTOR ALREADY MOVED
1128	8855	AD 62 A6				LDA	INVEC+2	;INVEC MOVED TO SCRA, SCRB
1129	8858				; HI BYTE OF EXEVEC MUST BE DIFFERENT FROM INVEC
1130	8858	CD 73 A6				CMP EXEVEC+1		;$FA, $FB USED AS RAM PTR
1131	885B	F0	15			BEQ	PTRIN
1132	885D	8D	3B	A6		STA	SCRA+1	;SAVE INVEC IN SCRA,B
1133	8860	AD 61 A6				LDA	INVEC+1
1134	8863	8D	3A	A6		STA	SCRA
1135	8866	AD 72 A6				LDA	EXEVEC	;PUT ADDR OF RIN IN INVEC
1136	8869	8D	61	A6		STA	INVEC+1
1137	886C	AD 73 A6				LDA	EXEVEC+1
1138	886F	8D	62	A6		STA	INVEC+2
1139	8872	AD 4B A6			PTRIN	LDA	P3H	;INIT RAM PTR IN $FA, $FB
1140	8875	85	FB			STA	$FB
1141	8877	AD 4A A6				LDA	P3L
1142	887A	85	FA			STA	$FA
1143	887C	18				CLC
1144	887D	60				RTS
1145	887E	20	88	81	RIN	JSR SAVER		;GET INPUT FROM RAM
1146	8881	A0	00			LDY #$0		;RAM PTR IN $FA, $FB
1147	8883	B1	FA			LDA	($FA),Y
1148	8885	F0	12			BEQ	RESTIV	;IF 00 BYTE, RESTORE INVEC
1149	8887	E6	FA			INC	$FA
1150	8889	D0	02			BNE	*+4
1151	888B	E6	FB			INC	$FB
1152	888D	2C	53	A6		BIT	TECHO	;ECHO CHARS IN ?
1153	8890	10	03			BPL	*+5
1154	8892	20	47	8A		JSR	OUTCHR
1155	8895	18				CLC
1156	8896	4C	B8	81		JMP	RESXAF
1157	8899	AD 3A A6			RESTIV LDA		SCRA	;RESTORE INVEC
1158	889C	8D	61	A6		STA	INVEC+1
1159	889F	AD 3B A6				LDA	SCRA+1
1160	88A2	8D	62	A6		STA	INVEC+2
1161	88A5	18				CLC
1162	88A6	20	1B	8A		JSR	INCHR
1163	88A9	4C	B8	81		JMP	RESXAF
1164	88AC 6C 6D A6				E3PARM JMP (URCVEC+1)			;... ELSE UNREC CMD
1165	88AF				; ***
1166	88AF				; *** HEX KEYBOARD I/O
1167	88AF				; ***
1168	88AF 20 88 81				GETKEY JSR SAVER			;FIND KEY
1169	88B2	20	CF 88			JSR	GK
1170	88B5	C9	FE			CMP	#$FE

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.

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ADC

TAX

SBC

P3L

TXA

TAX

CMP

II specifications