cardiograph-computer/2023-09-25.md

2023-09-25 — Dev notes

TODO

• Notes on possible architecture extensions to add support for a 16-bit IP

• add tape drive to mainframe

• review 8080 style io ports

  • works bc they have 2 operands per instruction, i think

Networking - first bits of research

• Bus network

• Econet

• Telnet

• Adding a serial port to my 6502 computer – Mike's Software Blog

• uxn networking — not helpful to me, i think

  • https://github.com/klardotsh/uxnyap
  • https://compudanzas.net/uxn_tutorial_day_7.html
  • https://hacklab.nilfm.cc/xrxs/about/

6502 vectors

https://www.masswerk.at/6502/6502_instruction_set.html

System Vectors

$FFFA, $FFFB ... NMI (Non-Maskable Interrupt) vector, 16-bit (LB, HB)
$FFFC, $FFFD ... RES (Reset) vector, 16-bit (LB, HB)
$FFFE, $FFFF ... IRQ (Interrupt Request) vector, 16-bit (LB, HB)

Docs leftovers: alternative table format for instructions

lo ↓ / hi →	0 (G0, M0)
0	END
1	NOP
2
3
4
5
6
7
8
9
A
B
C
D
E
F

lo ↓ / hi →	5 (G1, M1)	6 (G1, M2)
0	LDA #	LDA ind
1	STO #	STO ind
2	ADD #	ADD ind
3	SUB #	SUB ind
4	JMP #	JMP ind
5	JEQ #	JEQ ind
6	JFL #	JFL ind
7	FTG #	FTG ind
8	MUL #	MUL ind
9	DIV #	DIV ind
A	JLT #	JLT #
B	JGT #	JGT #
C	NOT #	NOT #
D	AND #	AND #
E	OR #	OR #
F	XOR #	XOR #

lo ↓ / hi →	9 (G2, M1)	A (G2, M2)
0	DEV #	DEV ind
1	INP #	INP ind
2	OUT #	OUT ind
3	FED	FED
4
5
6
7
8
9
A
B
C
D
E
F

lo ↓ / hi →	F (G3, M3)
0
1
2
3
4
5
6
7
8	RSL A
9	RSR A
A	ASL A
B	ASR A
C
D
E
F