Evolution of Conditional Tests

[J-F Garnier]

I always wondered why the 29C tests were so different from the 25/25C, but taking into account the intro date, it makes sense. The comparison tests of the 29C were aligned with the 67 and then adopted for the series 30.

(01-04-2020 12:58 AM)Sylvain Cote Wrote:  A little out of subject, but for the HP-41 the missing tests can be simulated:

Code:

X>=0?     X>=Y?       // missing test
INST.     INST.       // instruction to execute when the missing test is true
-----------------------------------------------------------------------------
X<0?      X<Y?        // reverse test
FS? 30    FS? 30      // always false (catalog in progress flag)
INST.     INST.       // instruction to execute when the missing test is true

Same trick can be used to port a 25/25C program using its specific tests to the HP67/29/33/34/11.

Code:

HP25  HP67/29/33/34/11
X>=0?     X<0?
INST.     X=0?
          INST.

But what about the X>=Y? and X<Y? tests that have no reverse on the HP67/29/33/34/11 ?
There is a 3-step solution for X>=Y? :

Code:

HP25  HP67/29/33/34/11
X>=Y?     X<=Y?
INST.     X=Y?
          INST.

J-F