[HP35S] Disassembling ROM

[Tugdual]

(02-24-2015 02:45 PM)matthiaspaul Wrote:  

(02-24-2015 01:46 PM)Thomas Ritschel Wrote:  What makes me puzzling is why these values are stored in the HP 35S in ASCII format and not as binary or BCD numbers...

Perhaps the compiler/assembler used didn't natively support the numerical data format used by those libraries, so that it would have been difficult to write those constants in the source code. If the data would have to be converted into another representation before it could be used, it wouldn't have harmed to store them in ASCII strings, anyway. ASCII strings of (almost) arbitrary length are supported by virtually all computer languages.

Another possibility might be that these numbers were meant to be patchable. It is quite common to store such numbers or strings in some easy recognizable and parsable format in binaries, so that they can be changed later on without having to recompile the sources, often even without having access to the sources (f.e. by OEMs or end-users).

Greetings,

Matthias

I would say for the sake of consistency. The constants are also stored using ASCII because we need to pick a constant on screen and then it is represented as a tiny EQN inside the code.
Also whatever constant is entered manually is the same, a mini ASCII EQN.
Of course this is to the detriment of performance.
I wonder if the whole calculator operates in ASCII, a bit like BCD but ASCII version. That would be pretty unique!