(HP71B) ASM question

[J-F Garnier]

(09-24-2024 12:00 PM)floppy Wrote:  AND: an overtaking of the GAMMA function of the Math module is currently analyzed: however, the BASIC ASM function I got from JF Garnier seems to use stack mechanisms I could not reconduct on Forth/ASM (for sure, the Forth has stack mechanisms). So, the idea is to have a GAMMA Forth/ASM (low prio); however the path to it is still not found. Any hints are welcomed.

The gamma asm code from the Math ROM (the dogam subroutine) should be useable in a Forth primitive, rewriting only the wrapper code to interface with the Forth environment.

The code is referring to a "math scratch stack", like:

Code:

     GOSUB  =stscr+   store it to math scratch stack
     GOSUB  =rcscr+   recall from math scratch stack

The HP naming is confusing, because there is also a "Math stack", specific to BASIC, to hold parameters and results during BASIC expression evaluation.
The "math scratch stack" is different, it's a reserved fixed place in the system memory implementing a 4-level stack to hold temporary extended precision values during numeric calculations.
So I believe it's perfectly useable in Forth too.

J-F