Edge Rewrite
// HTMLRewriter · presentation

This page was redesigned at the edge.

Cloudflare fetched the original article and streamed it through HTMLRewriter to apply an entirely new visual system without rebuilding the source page.

Jump to content

Talk:Overflow flag

Page contents not supported in other languages.
Add topic
From Wikipedia, the free encyclopedia
Latest comment: 3 years ago by 212.178.135.35 in topic Bitwise operations clearing the V-flag makes sense.

Use non signed numbers in explanation!

[edit]
)

pretty good explanation i don't care if there are no references lol it makes alot of sense please do not remove it just.... — Preceding unsigned comment added by 121.210.25.46 (talk) 10:42, 6 December 2011 (UTC)Reply

indeed its the appended paper is really usefull, so dont remove it even though its doesnt fullfill all guidelines — Preceding unsigned comment added by 83.76.248.163 (talk) 12:55, 22 June 2012 (UTC)Reply

Proof

[edit]

I'd like to get an explaination and/or proof why OF is a XOR of C(n) (sign bit) and C(n-1). Can anyone help? It could also be helpful to the article. Galzigler (talk) 15:02, 5 September 2016 (UTC)Reply

Bitwise operations clearing the V-flag makes sense.

[edit]

The article currently says:

"Bitwise operations (and, or, xor, not, rotate) do not have a notion of signed overflow, so the defined value varies on different processor architectures. Some clear the bit unconditionally".

Clearing the V-flag is handy for example when using TEST EAX,EAX to test if the register is zero. Because the sign and zero flags are set by TEST and the V-flag is cleared you do not only test if EAX is zero but can also use JL(E) or JG(E) which use the V-flag. This may be too detailed for this article? 212.178.135.35 (talk) 13:04, 18 October 2022 (UTC) Martin.Reply

OP writes: I phrased it briefly and more generally in the article.
Resolved
212.178.135.35 (talk) 10:07, 19 October 2022 (UTC) Martin.Reply