Documentation error [Resolved] - Parallax to fix

evanh

Just got meself a surprise to find an error in the Prop1 datasheet v1.4.0 - https://www.parallax.com/package/p8x32a-propeller-datasheet/

The instruction table, at top of page 23, the TEST instruction is said to set the Z flag when D = 0. This is wrong. The actual effect is when Result = 0.

EDIT: Also, the description should be changed from

AND S with D to affect flags only

to

AND S into D to affect flags only

Phil Pilgrim (PhiPi)

It's easy to see how this error crept in, since the test instruction is just an and instruction with the nr and wz modifiers. In an and instruction the destination is result after execution.

-Phil

VonSzarvas

Thanks @evanh - Submitted for update.

Yanomani

@evanh said:
Just got meself a surprise to find an error in the Prop1 datasheet v1.4.0 - https://www.parallax.com/package/p8x32a-propeller-datasheet/

The instruction table, at top of page 23, the TEST instruction is said to set the Z flag when D = 0. This is wrong. The actual effect is when Result = 0.

Good catch!

The error seems to also be due an indecision on the way prepositions are used: "with" in place of "into".

And it also affects the next item at the Assembly Instruction Table (TESTN); both are conflicting in that aspect, and cannot be simultaneouslly right.

IMHO, since neither of those two instructions modify D contents, both would be better explained by the use of "with" at their descriptions, and sure, Z Result-column needs to be equal for them, but as you know, english isn't my first language...

evanh

Huh, TEST does say "with" when the others say "into". The two errors must have been some copy'n'paste hangover that oddly wasn't corrected for this one instruction ... Opening post has been updated with this.

Phil Pilgrim (PhiPi)

I think "with" is more correct than "into" for test. "Into" is a bit misleading since it implies D could be changed. Besides, ANDing is commutative:

S & D == D & S

-Phil

Jeff Martin

Thanks @evanh, @"Phil Pilgrim (PhiPi)", and @Yanomani.

This was probably a copy/paste issue, ultimately. I don't recall if that specific datasheet content came from me, or if I used it as the basis for the Quick Reference, but I also see that the Propeller Quick Reference v1.7 has a similar discrepancy and also a similar problem with TESTN, and TESTN in the manual uses the "into" language where I'd prefer it not to.

My intention is to use the term "with" instead of "into" since the normal operation of TEST and TESTN is not to store the result into D, and also to make the Z Result field be "Result = 0" instead of "D = 0."

Again, thanks for catching this!

evanh

Cool, thanks.