WP 34S是一个在国外hp玩家中相当出名的自制项目，初衷是在HP-20b这一款HP开放编程接口的便携式金融计算器上实现自制rom，现在该项目完成度已很高，能够给HP-20b和30b两款机器提供顶级按键编程机的机能（官方说是42s和16c的混合体，这两台机器已经是按键编程机的顶峰了），最大化地利用了HP20系机器的硬件，受到普遍支持。 (引用来源：http://lithiumzone.sinaapp.com/?p=803） WP 34S同样也是开源的，在PC和iOS上都有模拟器（Simulator），代码风格很好。最近想研究研究RPN，于是就把模拟器移植到了目前最流行的学生计算器——TI Nspire。
The WP 34S function set is based on the famous HP-42S RPN Scientific, the most powerful programmable RPN calculator built so far. We expanded this set, incorporating the functionality of the renowned programmer‘s calculator HP-16C, the fraction mode of the HP-32SII, probability distributions as featured by the HP-21S, and added many more useful functions for mathematics, statistics, physics, engineering, programming, like:
- Euler's Beta function, Fibonacci numbers, Lambert's W (all of these in real and complex domains), the error function, incomplete regularized Beta and Gamma, Riemann‘s Zeta, the most popular orthogonal polynomials, testing for primality,
- many statistical distributions and their inverses like Poisson, Binomial, Geometric as well as Cauchy-Lorentz, Exponential, Logistic, Weibull for reliability analysis, Lognormal and Gaussian with arbitrary means and standard deviations,
- programmable sums and products, first and second derivatives,
- extended date and time calculations based on a real time clock,
- integer computing in arbitrary bases from binary to hexadecimal,
- financial operations like mean rate of return and margin calculations,
- 80 conversions, mainly between universal SI and old Imperial units,
- 50 fundamental physical constants as precise as known today by national standards institutes like NIST or PTB, plus
- some more out of mathematics, astronomy, and surveying,
- complete Greek and extended Latin letter fonts covering many languages on this planet (upper and lower case in two font sizes each).
For the uninitiated (to HP calculators) this means the WP-34s supports the following:
- Reverse Polish Notation - does not support chain or algebraic mode.
- logarithmic and trigonometric functions, including their hyperbolic and inverse functions.
- statistics: sum, mean, standard deviation and many other functions
- RPN keystroke programmable à la HP-41 - over 500 steps - numeric and/or alpha labels, 4554 steps burnable into flash banks.
- probability functions: x!, combinations, permutations etc..
- conversion between degrees, radians and gradians; rectangular and polar co-ordinates, decimal and
- hours:minutes:seconds; binary, octal, decimal and hex, decimal, fractions and improper fractions, not to mention some 80 unit convsions.
- Equation solver - finds f(x) = 0
- Numeric integration and 1st and 2nd derivative.
- Binary, octal or hexadecimal arithmetic.
- Most functions support complex numbers.
使用方法和WP 34S一致，额外的寄存器显示可以使用Sketchpad键来切换，按键映射图可以按Var键唤出。 关于WP 34S的使用方法，请阅读 WP 34S用户手册：http://sourceforge.net/projects/wp34s/files/doc/