HP-70 Emulator - Scientific pocket calculator from 1973

Control & Timing
Current Address	0000
Return Address	0000
Pointer	0

	0	1	2	3	4	5	6	7	8	9	A	B	C	D
Status	○	○	○	○	○	○	○	○	○	○	○	○	○	○

Arith & Regs		Sign	Mantissa										Exponent
Register A		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register B		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register C		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register D		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register E		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register F		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register M		0	0	0	0	0	0	0	0	0	0	0	0	0	0

Data Storage		Sign	Mantissa										Exponent
Register 0		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 1		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 2		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 3		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 4		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 5		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 6		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 7		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 8		0	0	0	0	0	0	0	0	0	0	0	0	0	0
Register 9		0	0	0	0	0	0	0	0	0	0	0	0	0	0

HEWLETT•PACKARD 70

Calendar Functions

Data entry sequence is: month, decimal point, two numeral day and four numeral year.
Example: May 8, 1972 = 5.081972
To obtain difference between two dates:

Key in first date and press SAVE↑
Key in second date and press DAY

To obtain a date from a base date:

Key in base date and press SAVE↑
Key in the number of days and press the shift key then DAY (DATE)

Compound Interest

Future Value:

Key in number of time periods and press n
Key in interest rate per time period (in %) and press i
Key in present value (principal) and press PV then FV

Rate of Return (growth rate) effective rate per period in %.

Key in number of time periods and press n
Key in present (beginning) value and press PV
Key in future (ending) value and press FV then press i

What is this?

This is an emulation of the HP-70, from 1974, running on two different CPUS - the HP Control & Timing chip and the HP Arithmetic & Register chip. Alongside the two CPUs there are 3 ROM chips, a "Data Storage" (560 bits) chip, a keyboard, and a display, all being emulated with perfect synchronization.

Source code

It is my dream to build a chip library for anyone to be able to emulate any chip or board. Therefore, the code is subdivided into several layers of emulation:

Acknowledgments / Resources

This emulation would be lacking without the resources below: