[fpc-devel] x86 TEST instruction

J. Gareth Moreton gareth at moreton-family.com
Thu Jun 30 17:28:47 CEST 2022

This was what I was working on:


The same question applies regarding the TEST instruction, but it's a 
little more restrictive in this instance in that it's determined that 
the program doesn't care about the upper bytes of the register once the 
optimisation is made, so "testl $1,%ebx" is indeed the same as "testb 
$1,%bl" due to previous logic, but I am wondering if a penalty might be 
incurred due to the partial read or if this is only a concern for 
partial writes.

Gareth aka. Kit

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